OF HEAVY MASS

FIELD OF INVENTION

[001] This invention relates to a massive energy storage system. It is based on gravitational potential energy in heavy mass stored in a container, which is moved vertically or nearly vertically between a low platform and a high platform

[002] Energy storage is becoming ever-more important due to wide-spread renewable energy generation. Due to its intermittency of the generation, massive energy storage is of paramount importance for an independent grid or islanded microgrid to be self-sustainable and self- sufficient In this invention, the developed new massive energy storage system can be adopted to cope with such demand and challenge and other applications.

BACKGROUND

[003] Re-vamping existing distributed power systems is an ongoing world-wide project in order to maximize the harnessing of renewable energy generation. This is a part of progress towards future smart grid. The smart grid ideally is formed by many microgrids/grids, each of which or most of which have the capability to operate in islanded mode.

[004] The renewable energy mainly includes wind energy, solar energy, geo-thermal energy and tidal wave energy etc. Most of them are intermittent. To cope with such intermittence, massive energy storage is indispensable. Currently there are many existing energy storage systems, such as battery storage, pumped-hydro storage, fly-wheel storage, super-conducting magnetic energy storage, super-capacitor energy storage etc. Each of them has pros and cons.

[005] Battery storage is the most convenient one but its price is quite high. A battery energy storage with 1kWh capability costs around 150USD. For massive energy storage, it may not be suitable due to this high price.

[006] Pumped-hydro storage using water reservoir is a feasible one only when there is spacious space and water available. [007] In USA patent US 8,593,012 B2, the inventors proposed to use trains to drive the heavy mass from low platform to high platform to store energy. In such energy storage system, energy losses due to friction are quite high, making overall system efficiency low.

[008] To overcome the limitations in the existing energy storage systems, this invention introduces a heavy mass based energy storage system with less losses by shifting the heavy mass vertically or nearly vertically from low platform to high platform. The heavy mass can be iron ore or other materials with high mass density and relatively affordable prices. The heavy mass is stored in a container, which is moved between low platform and high platform. The container could be moulded steel -reinforced plastic one or others. The main issue in such a heavy mass energy storage system is energy loss due to friction. To solve this issue, this invention worked out a new linear machine system, which moves the heavy mass stored in a container vertically or nearly vertically to reduce friction. Such massive energy storage system could be built in a mountain, where the top of the mountain and some of the mountain interiors can be used to construct multi-layer high platforms, and the foot of the mountain could be used to build the lower platforms. One may dig vertically or nearly vertically and build the low-platforms underground and build the high platforms at the top of small mound or on the ground. It can also be built in the sea/river. Or one may construct a pole- bar grid on land which contains many vertical poles and horizontal bars joining vertical poles at both low and high platforms. The containers could be hung on the bars or stationed on the platforms formed by the bars at both low and high platforms. Multiple machine systems are installed in the pole-bar grid system for lifting up or lowering down the containers. Such pole-bar system can be built either on land or in sea/river. The most convenient and cheapest way could be to build tracks along the slope of a mountain/mound or river/sea side between their banks and beds, which have steep slopes. One may also build such heavy mass energy storage along the vertical banks of deep ports.

SUM MARY

[009] The present invention overcomes or ameliorates at least one or more of the disadvantages of the prior art, or to provide a useful alternative.

[0010] This invention is on a massive energy storage system using potential energy in heavy mass stored in a container which is moved vertically or nearly vertically from a low platform to a high platform by operating the system as a motor, when there is surplus energy in grid/mi crogrid due to renewable energy generation; vice versa, when there is a shortage of renewable energy generation, the container with the heavy mass is lowered down to the low platform from high platform by operating the system as a generator. The energy is exchanged between potential energy in the heavy mass and electric energy in the AC microgrid/power grid through power electronics converters.

[0011] Such heavy mass energy storage system can also be used to ride through peak power demand in a power grid. When there is less power demand, extra energy from generations is stored in the heavy mass energy storage system At peak power demand hours, the stored energy in the heavy mass is released to the power grid.

[0012] According to a first aspect of the invention, there is provided a heavy mass energy storage system, comprising containers with heavy masses; vertical supporting poles or supporting tracks mounted on the slope of a mountain/ mound or supporting tracks installed along the river/sea sides between their banks and beds; one passage or more passages for lowering down the containers; one passage or more passages for lifting up the containers; one or more high platforms at one layer or multiple layers for parking the containers; one or more low platforms at one layer or multiple layers for parking the containers; an integral body for lifting up and moving with each container with the heavy mass along supporting poles or tracks, the integral body consisting of the moveable parts of a linear machine for lifting up or lowering down each container either vertically or nearly vertically along the supporting poles or tracks each time, the linear machine being either one of two configurations, the first configuration containing one or multiple nearly closed-loop magnetic paths spreading from the top to the bottom of a passage; one or multiple sets of set-S conductors, with DC current flowing through them for producing constant magnetizing field, spreading from the top to the bottom of a passage, with each set being placed inside one nearly closed-loop magnetic path; one or multiple sets of DC-current- carrying set-R insulated conductors embedded in permeable magnetic plates with both conductors and plates being part of the integral body, the magnetic plates being spreading almost the same distance as the set-R conductors along the direction of movement of the container; the conductors in each set of set-R being divided into multiple groups with each group having the same number of conductors, each group being connected in parallel and all the groups being divided into one or multiple subgroups, with each subgroup connected in series with series connection being arranged either on the top of the plates or at the bottom of the plates; the second configuration containing one or multiple nearly closed-loop magnetic paths spreading from the top to the bottom of a passage along which the container with the heavy mass is transported, the magnetic paths adopting interleaved or alternating magnetic configuration with one layer being permeable material and neighbouring layer being non-permeable material along the direction of movement of the container, each layer having the same height one or multiple sets of set-S conductors with DC current flowing through them for producing constant magnetizing field, spreading from the top to the bottom of a passage, with each set being placed inside one nearly closed-loop magnetic path; one pair or multiple pairs of AC-current-carrying set-R conductors being part of the integral body, each of two sets in one pair of the set-R conductors containing two parts being insulated and embedded in magnetic materials, named as Y -bar part and X-bar part, with vertical distance between Y -bar part and X-bar part being the same or nearly the same as the height of each layer either permeable or non- permeable, Y -bar part being placed between stationary interleaved magnetic plates spreading from the top to the bottom of a passage and X-bar part passing through the air gaps in each interleaved nearly closed- loop magnetic path spreading from the top to the bottom of a passage, with two parts being joined together by conductors with non-permeable mechanic reinforcement, and with the second set of the set-R conductors in one pair producing uplifting electromagnetic force during the transition of the first set of set-R conductors between permeable and non- permeable layers; mechanic connection and reinforcement parts for mechanical coupling between the integral body, the container and the supporting poles or tracks; converter circuits for providing DC current to the set-S conductors and for providing DC or AC currents in the set-R conductors; terminal connections for the set-R conductors with converters.

[0013] According to a second aspect of the invention, there is provided a method for operating the heavy mass energy storage system, wherein a constant current is produced by a separate AC/DC converter connected with an AC grid/mi crogrid or a separate DC/DC converter connected with a DC grid/mi crogrid to flow in each individual circuit formed by the set-S conductors for generating constant DC magnetic field between two walls; a group of bidirectional converters are installed at one platform, are to power each individual circuit formed by the set-R conductors mounted on the integral body for lifting the container to work in either motoring or generating modes; for each uplifting passage, at least one such group of bidirectional converters is used; for each lowering-down passage, at least another one such group of bi-directional converters is used.

[0014] According to a third aspect of the invention, there is provided a method for operating the heavy mass energy storage system, in which the integral body is adopted to lift up or lower down each container; in a vertical or nearly vertical passage for lifting up the container system to store energy, each time after the container system reaches the top of the vertical or nearly vertical passage, it is dismounted from the container and moved down along the supporting poles or tracks to the bottom of the vertical or nearly vertical passage for lifting up next container; during the downward movement, the integral body together with the set-S conductors is operated in a generating mode to release the potential energy in the integral body and feed the power generated to power grid; in a vertical or nearly vertical passage for lowering down the container system to release potential energy to generate electricity, each time after the container system reaches the bottom of the vertical or nearly vertical passage, it is dismounted from the container and moved up along the supporting poles or tracks to the top of the vertical or nearly vertical passage for lowering down next container; during the upward movement, the integral body together with the set-S conductors is operated in a motoring mode. Consumed power by the system from the power grid is converted into the potential energy gain in the integral body.

[0015] According to a fourth aspect of the invention, there is provided a method for managing the movement of container on either high or low platforms in the heavy mass energy storage system, wherein there are two sets of horizontal movers, the first sets and the second sets; the second set is for receiving the container from the exit of a vertical or nearly vertical passage, then shifting to the first set of the horizontal mover, from which the container is transferred to the parking tracks of the parking platform; or for sending the container to the entrance of a vertical or nearly vertical passage from the first set of horizontal mover; the first set of horizontal mover is to receive the container from the second set of horizontal mover when the container arrives from a vertical passage, then to move it to the parking tracks of the platform; or to move the container from the parking platform to the second set of horizontal mover when the container is to be transferred, then to be lowered down from a vertical or nearly vertical passage; the second the exit of a uplifting passage or the entrance of a lowering-down passage. [0016] According to a fifth aspect of the invention, there is provided a system adopting the heavy mass energy storage system, wherein a floating artificial island or a real island with protruding support around it or a series of floating artificial islands or floating platforms are built on the surface of sea/river with positioning poles or tracks; the heavy mass energy storage system is built with the artificial or real islands, wherein low and high parking platforms are built under the sea/river; some or all of the parked containers at high and/or low platforms are hung to the artificial or real islands or to other floating buoys either under sea/river or at its surface through rope-l i ke or sol id- rod mechanic systems.

[0017] According to a sixth aspect of the invention, there is provided a pole-bar grid system adopting the heavy mass energy storage system, wherein a plurality of poles are planted vertically on earth; horizontal bars are to join the vertical poles to form the pole-bar grid; the heavy mass energy storage system is adopted to store the energy, wherein low and high parking platforms are built using bars with the support of poles.

[0018] According to a seventh aspect of the invention, there is provided a method for building the platforms in the heavy mass energy storage system, in which the platforms are built between two passages, one for lifting up container while the other for lowering down the container; there are multiple tracks on each platform; there is a downward slope at each high platform pointing from the uplifting passage to the lowering-down passage; there is a downward slope at each low platform pointing from the lowering-down passage to the uplifting passage.

[0019] According to an eighth aspect of the invention, there is provided an interleaved linear machine as illustrated in the heavy mass energy storage system, in which one or multiple nearly closed-loop magnetic paths spreading from the beginning to the end of a passage along which the machine moves, the magnetic paths adopting interleaved or alternating magnetic configuration with one layer being permeable material and neighbouring layer being non-permeable material along the direction of movement of the machine, each layer having the same length; one or multiple sets of set-S conductors with DC current flowing through them for producing constant magnetizing field, spreading from the beginning to the end of a passage, with each set being placed inside one nearly closed-loop magnetic path; one pair or multiple pairs of AC-current- carrying set-R conductors being part of the integral body, each of two sets in one pair of the set- R conductors containing two parts being insulated and embedded in magnetic materials, named as Y -bar part and X -bar part, with a distance between Y -bar part and X -bar part bei ng the same as the length of each layer either permeable or non- permeable, Y -bar part being placed between stationary interleaved magnetic plates spreading from the beginning to the end of a passage and X -bar part passing through the air gaps in each interleaved nearly closed-loop magnetic path spreading from the beginning to the end of a passage, with two parts being joined together by conductors with non-permeable mechanic reinforcement, and with the second set of the set-R conductors in one pair producing driving electromagnetic force during the transition of the first set of set-R conductors between permeable and non- permeable layers.

B R IE F D E SC RIPTIO N O F T H E D RAWING S

[0020] Figure 1 a shows container with heavy mass and part of positioning or supporting poles, and grooves;

[0021] Figure 1 b shows cut cross section of the container system with the set-S and set-R conductors and permeable plates;

[0022] Figure 2a shows container and its positioning or supporting poles, trough, the rest cavity for the pole stopper, grooves;

[0023] Figure 2b shows magnified cross sectional view of poles ^" positioning mechanism in Fig. 2a, including bearings mounted on the three-side surfaces of the container, the bearings being all the way along vertical direction of the container, bearings mounted on the side surface of pole stopper;

[0024] Figure 2c shows magnified pole stopper and its movement facilitator, including two bars in rectangular shape sitting on bearing structure through two channels inside it, which can be moved along the bearings horizontally, and another rod fixed to the pole stopper, which is for pushing or pulling the pole stopper from its rest cavity to position for fastening the supporting poles;

[0025] Figure 3a shows the system with the set-S conductors, and permeable plates such as si I icon- iron or steel which extends through the whole passage linking high and low platforms;

[0026] Figure 3b shows the terminal connection of the set-S conductors at one end of the vertical passage; [0027] Figure 3c shows the terminal connection of the set-S conductors at another end of the vertical passage;

[0028] Figure 3d shows the interleaved structure with both highly permeable materials such as steel or si I icon- iron and low permeable material or non- permeable permeable along the direction of the movement of the contai ner to save cost

[0029] Figure 4 shows (a) vertical cut cross section through A1A2 as seen from Fig. 3a, which contains permeable plates through the whole passage linking high and low platforms, the set-R current-carrying conductors, position-fixtures; (b) one illustration of series and/or parallel connections of some of the set-R conductors; (c) arrangement of connections to join the set-R conductors in series and/or in parallel; (d) a vertical side view of the container system; (e) integral body A which is shared by all containers and can move along the supporting poles acting as either generator or motor with the set-S conductors;

[0030] Figure 5a shows the system with set-S conductors, and several of the set-R conductors and DC power supplies to the two sets of conductors;

[0031] Figure 5b shows side view of a heavy mass energy storage system for its movement along the steep slope of a mountai n or sea/river side between its bank and sea bed;

[0032] Figure 5c shows top view of a heavy mass energy storage system with three guiding poles for its movement along the steep slope of a mountain or sea/river side between its bank and sea bed;

[0033] Figure 5d shows side view of the integral body which is shared by all the containers and i ntegrated with the supporti ng or gui di ng pol es;

[0034] Figure 6 shows the horizontal cut cross section of a second possible structure of the system with three supporting poles, and a concrete shell in rectangular shape, made of steel or other rigid materials reinforced concrete;

[0035] Figure 7a shows horizontal cut cross section of third possible structure of the energy storage system with two supporting poles, and two set-S conductors, and one set-R conductors, two nearly-closed magnetic paths, and two plate rows of the set-R conductors ^" terminal connection; [0036] Figure 7b shows horizontal cut cross section of the modified third possible structure of the energy storage system with two nearly closed magnetic paths, and two plate rows of conductors ^" termi nal connecti on and three supporti ng pol es for steep si ope appl i cati ons;

[0037] Figure 7c shows a part of the half of magnetic paths in the structure in Fig. 7b spanning from the bottom to the top of a passage and with two si ots for the termi nal connecti ons of the set- R conductors;

[0038] Figure 7d is similar to the configuration as shown in Fig. 7b but with no air gaps formed by mechanic strengthening parts;

[0039] Figure 7e shows one possible configuration of the moveable components in the structure as shown in Fig. 7d;

[0040] Figure 7f shows the second possible configuration of the moveable components in the structure as shown in Fig. 7d with the conductors insulated and embedded in the moveable magnetic materials;

[0041] Figure 7g illustrates another possible configuration with only one nearly-closed magnetic path and one set-S conductors;

[0042] Figure 7h illustrates the arrangement of conductors in the interleaved configuration;

[0043] Figure 8a shows the top view of an interleaved structure;

[0044] Figure 8b shows part of the nearly-closed magnetic paths with the set-R conductors in Fig. 8a;

[0045] Figure 8c shows the set-R -subset- 1 and set-R-subset-2 conductors used in the interleaved structure in Fig. 8a;

[0046] Figure 8d shows currents in the set-S conductors, set-R -subset- 1 conductors and set-R- subset-2 conductors for the adopti on of i nterl eaved structure i n F i g. 8a;

[0047] Figure 8e illustrate top-view of a second possible arrangement of the interleaved structure;

[0048] Figure 8f shows top-view of the two pairs of set-S conductors and one set-R conductors and mechanic support in the second possible arrangement of the interleaved structure in Fig. 8e;

[0049] Figure 8g shows the top-view of the interleaved magnetic structure in Fig. 8e;

[0050] Figure 8h illustrates the cross sectional view from the cross section of A1 A 2 in Fig. 8e;

[0051] Figure 8i shows the cross sectional view from the cross section of B1 B2 in Fig. 8e; [0052] Figure 8j shows the cross sectional view from the cross section of C1 C2 in Fig. 8e;

[0053] Figure 8k shows the cross sectional view from the cross section of D1 D2 or E 1 E2 in Fig. 8e;

[0054] Figure 8I shows the two sets of set-R conductors for the second interleaved structure as shown in Fig. 8e;

[0055] Figure 8m illustrates top-view of a third possible arrangement of the interleaved structure;

[0056] Figure 8n shows top-view of the three pairs of set-S conductors and two sets of set-R conductors and mechanic support in the third possible arrangement of the interleaved structure in Fig. 8m

[0057] F i gure 8o shows the top-v i ew of the i nterl eaved magneti c structure i n F i g. 8m;

[0058] Figure 9a shows one possible structure of energy storage system with two platforms and two vertical passages;

[0059] Figure 9b shows the top view of each platform in Fig. 9a;

[0060] Figure 9c shows details of the first set of horizontal mover, containing two horizontal tracks, rail where the container can sit, push-pull locomotive;

[0061] Figure 9d shows details of the second set of horizontal mover, containing two horizontal tracks, rail where the container can sit, push-pull locomotive;

[0062] Figure 10 shows vertical cut cross sectional view of the structure in Fig. 9a;

[0063] Figure 11 shows vertical cut cross sectional view of a system with multiple layers of both high platforms and low platforms, and multiple uplifting and lowering-down passages;

[0064] Figure 12 shows equivalent circuit of the system working in the motoring mode with increased potential energy in the heavy mass when the container is lifted from low to high platforms along the vertical passage;

[0065] Figure 13 shows equivalent circuit of the system when working in the generating mode with reduced potential energy in the heavy mass when the container is lowered down from high to low platforms along the vertical passage;

[0066] Figure 14 shows cable connection system to power the set-S conductors installed in the two walls, and to power the set-R conductors mounted on the integral body through a cabling system and pulley system [0067] Figure 15a shows the diagram for calculating magnetic field in the region between two walls, which is produced by the set-S conductors embedded in the two walls;

[0068] Figure 15b x-direction magnetic field between two walls calculated from exact method;

[0069] Figure 15c y-direction magnetic field between two walls calculated from exact method;

[0070] Figure 16a shows multiple identical AC/DC/DC converter circuits for working with the different circuits formed by the set-R conductors;

[0071] Figure 16b shows multiple identical AC/DC/DC converter circuits in parallel to supply higher current;

[0072] Figure 17 shows equivalent circuits: (a) during the operation in motoring mode for lifting up the container from low platform to high platform; (b) during the operation in generating mode for I oweri ng down the contai ner from hi gh pi atf orm to I ow pi atf orm;

[0073] Figure 18 shows controller for the steady-state operation: (a) during motoring mode or duri ng I i fti ng up the contai ner from I ow pi atf orm to hi gh pi atf orm; ( b) duri ng generati ng mode or during lowering down the contai ner from high platform to low platform.

D E F INIT IO NS

[0074] The following definitions are provided as general definitions and should in no way limit the scope of the present invention to those terms alone, but are put forth for a better understand! ng of the f ol I owi ng descri pti on.

[0075] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. For the purposes of the present invention, additional terms are defined below. Furthermore, all definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms unless there is doubt as to the meaning of a particular term, in whi ch case the common di cti onary def i niti on and/or common usage of the term wi 11 prevai I . [0076] All of the publications cited in this specification are herein incorporated in their entirety by cross-reference.

[0077] For the purposes of the present i nventi on, the fol I owi ng terms are defi ned bel ow.

[0078] The articles ^' a _. and ^' an _. are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, "an element" refers to one element or more than one element.

[0079] The term ^' about _, is used herein to refer to quantities that vary by as much as 30%, preferably by as much as 20%, and more preferably by as much as 10% to a reference quantity. The use of the word : about ^" to qualify a number is merely an express indication that the number is not to be construed as a precise val ue.

[0080] Throughout this specification, unless the context requires otherwise, the words ^' comprise _. , ^' comprises _, and ^' comprising _, will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements.

[0081] Any one of the terms: ^' including _, or ^' which includes _, or ^' that includes _, as used herein is also an open term that also means including at least the elements features that follow the term, but not excluding others. Thus, ^' including _, is synonymous with and means ^' comprising _. .

[0082] The term, ^' real-time _. , for example ^' displaying real-time data, _, refers to the display of the data without intentional delay, given the processing limitations of the system and the time required to accurately measure the data.

[0083] The term ^' near-real-time _. , for example ^' obtaining real-time or near- real -time data _, refers to the obtaining of data either without intentional delay ( ^' real-time _. ) or as close to realtime as practically possible (i.e. with a small, but minimal, amount of delay whether intentional or not within the constraints and processing limitations of the of the system for obtaining and recordi ng or transmitti ng the data.

[0084] Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. It will be appreciated that the methods, apparatus and systems described herein may be implemented in a variety of ways and for a variety of purposes. The description here is by way of example only. [0085] As used herein, the term ^' exemplary _, is used in the sense of providing examples, as opposed to indicating quality. That is, an ^' exemplary embodiment _, is an embodiment provided as an example, as opposed to necessarily being an embodiment of exemplary quality for example serving as a desirable model or representing the best of its kind.

[0086] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0087] The phrase ^' and/or, _ as used herein in the specification and in the claims, should be understood to mean ^' either or both_ of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with ^' and/or_ should be construed in the same fashion, i.e., One or more_ of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the ^' and/or_ clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to Ά and/or B _, when used in conjunction with open-ended language such as ^' comprising _, can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0088] As used herein in the specification and in the claims, ^' or_ should be understood to have the same meaning as ^' and/or_ as defined above. For example, when separating items in a list, ^' or_ or ^' and/or_ shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as ^' only one of _ or ^' exactly one of, _ or, when used in the claims, ^' consisting of _ will refer to the inclusion of exactly one element of a number or list of elements. In general, the term ^' or_ as used herein shall only be interpreted as indicating exclusive alternatives (i.e. ^' one or the other but not bothj when preceded by terms of exclusivity, such as ^' either,_ ^' one of,_ ^' only one of,_ or ^' exactly one of._ ^' Consisting essentially of,_ when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0089] As used herein in the specification and in the claims, the phrase ^' at least one,_ in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase ^' at least one_ refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, ^' at least one of A and B _ (or, equivalently, ^' at least one of A or B, _ or, equivalently ^' at least one of A and/or B J can refer, in one embodiment to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0090] In the claims, as well as in the summary above and the description below, all transitional phrases such as ^' comprising, _, ^' including, _, ^' carrying, _, ^' having, _, ^' containing, _, ^' involving, _, ^' holding, _, ^' composed of, _, and the like are to be understood to be open-ended, i.e., to mean ^' including but not limited to _. . Only the transitional phrases ^' consisting of _. and ^' consisting essentially of _. alone shall be closed or semi-closed transitional phrases, respectively.

[0091] For the purpose of this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be carried out in chronological order in that sequence, unless there is no other logical manner of interpreting the sequence.

[0092] In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognise that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.

Set-S conductors [0093] Set-S conductors are defined for the vertical conductors, which are the stator conductors in a machine. There are at least two sets of such conductors, each set of conductors being placed vertically at one side of permeable plates. Each set contains multiple conductors in parallel and arranged side by side. Each set forms a wall. Two sets, one each being at each of the two sides of the permeable plates form a pair of walls. There may be more than two sets, such as four sets, each of two sets being placed at one side of the permeable plates. Solid conductors embedded in a rigi d wal I are adopted for the set-S conductors. A 11 the set-S conductors from a pai r of the wal Is can be divided into several groups. The conductors in each group are connected in series to form an individual circuit, which is supplied by either a DC source or by a DC current from an AC source via a separate AC/DC converter.

Set-R conductors

[0094] Set-R conductors are to produce the lifting electromagnetic forces to lift up or lower down the container. They are the rotor conductors in a machine. There are joining parts for the set-R conductors to achieve series and/or parallel connection. There may be more than one set of set-R conductors in each heavy mass energy storage system The electromotive force inducing part of the set-R conductors are placed between and perpendicularly to a pair of walls with the embedded set-S conductors. Reinforcement is adopted to integrate the set-R conductors with the other parts of the i ntegral body to bear the el ectromagneti c force.

The fi rst set of horizontal mover

[0095] The first set of horizontal mover is defined as an electric and mechanic device which shifts the container horizontally at each platform to transfer the container from the second set of horizontal mover as described immediately below to the tracks onto a parking platform with multiple parking tracks, or to transfer the container from the tracks of the parking platform to the second horizontal mover as described immediately below. It is formed by a rail, where the container can sit, two tracks, which support the rail to move along them, locomotive, which could push or pull the rail with the container horizontally along the two tracks.

The second set of horizontal mover [0096] The second set of horizontal mover is defined as an electric and mechanic device which shifts the container from the exit of a lifting-up passage to the first set of horizontal mover, or shift the container from the first set of horizontal mover to the entrance of a lowering-down passage. It is formed by a rail, where the container can sit, two tracks, which support the rail to move along them, locomotive, which could push or pull the rail with the container horizontally along the two tracks. The tracks are horizontally moveable. This is because the two tracks need be used for bridging the exit of a passage when the container reaches there, and also for bridging the entrance of a passage when sendi ng a contai ner from there.

A nearly-closed magnetic path

[0097] A nearly closed-loop magnetic path is defined as a loop path along which most parts are formed by magnetic or permeable materials except those parts occupied by current-carrying set- R conductors insulated and embedded in permeable magnetic materials. There is one set of set-S conductors enclosed by each nearly closed-loop magnetic path, through which the magnetizing field is produced. Such nearly- closed magnetic paths spread from the top to the bottom of a passage. In an interleaved structure, such nearly closed-loop magnetic paths ^" layers alternately join along the direction of movement of the container with one layer being formed by permeable materials and the neighbouring layer being formed by non- permeable materials. The overall nearly closed-loop magnetic path from the top to the bottom of a passage is supported mechanically to have sufficient strength to stand vertically or nearly vertically.

D ETAIL E D D E SC R IPT IO N

[0098] Massive energy storage is an indispensable forming component in an independent grid or an islanded microgrid for self-sustainable and self-sufficient operation. Currently pumped hydro storage can achieve such requirement. Nevertheless it takes quite much space and there are also issues of water evaporation and availability of water. In comparison, potential energy storage using heavy mass such as iron ore etc could potentially be a good substitute of pumped hydro storage based energy storage. This is because some heavy mass such as iron ore or other heavy masses has a mass density several times as high as that of water. Hence such energy storage system takes less space. Furthermore the heavy masses can be repetitively used for many years. In USA patent US 8,593,012 B2, the inventors proposed to use trains to drive the heavy mass from low platform to high platform to store energy. In such energy storage system, energy losses due to friction are quite high, making overall system efficiency low.

[0099] To make heavy mass based energy storage a feasible solution, efficiency issue needs be solved first In this invention, a new method is proposed to minimize friction when moving the heavy masses from low platform to high platform or vice versa. The key forming components in the system and how each one works are described below.

[00100] Container 100 which stores heavy masses such as iron ore etc is shown in Fig. 1a and Fig. 2a. Positioning or supporting poles 200 and 201 are shown in Fig. 2a, which could be made of assemble-able multiple segments. The grooves 290, 291, 292 and 293 as shown in Fig. 1a are for sliding in the container with heavy mass into linear machine system for lowering down or lifting up movement When the container reaches either low or high platform, the pole stoppers 255 shown in Fig. 2b and 2c are moved to their respective rest cavity 220 in Fig. 2a and Fig. 2b. Then the container is shifted to the second set of horizontal mover such as 340 in Fig. 9b at either low or high platform, and the container is moved along opposite directions of the troughs 230 in Fig. 2a.

[00101] Figure 1 b shows the cross sectional view of the container with the linear machine system, where the cut cross sections of the two set-S conductors 110 and 111, permeable magnetic plates 240, and part of the set-R conductors 250 are included.

[00102] Figure 2c shows details of the pole stopper 255, which includes two bars 251 in rectangular shape sitting on bearing structure 253 and 254, which can be moved along the bearings horizontally, and another rod 252 fixed to the main part of the pole stopper. A push-pull motor i s i nstal I ed on the contai ner to push the pol e stopper i n order to fasten the supporti ng pol es at departing position, or to pull the pole stopper when the container reaches the exit of the vertical passage to allow the shifting of the container out of the passage to the second set of horizontal mover 340 in Fig. 9b.

[00103] There is a concave in the container as shown in Fig. 1a, Fig. 1 b, and Fig. 2a where two walls with the embedded set-S conductors 110 and 111 (see Fig. 1 b) are placed, one each on each side of the permeable plates. By using smaller distance between two walls, a more uniform magnetic field Hi _a and Hib as shown in Fig. 3a is produced in the region between two walls by the currents f lowi ng through the set-S conductors.

[00104] As highly permeable materials such as steel or silicon-iron is quite expensive, one possible solution to save the cost is shown in Fig. 3d, where interleaved structure is adopted to replace each of the vertical permeable plates as shown in Fig. 3a. It contains both highly permeable material such as steel or si I icon- iron and low- permeable 240 or non- permeable solid material 260. When adopting such structure, more set-R conductors spanning longer along the direction of supporting poles need be adopted to produce sufficient induced voltage, then energy exchange.

[00105] All the set-S conductors embedded in the two walls are divided into a certain number of groups. The conductors in each group are connected in series to form an individual circuit, which is powered by a DC source or by an AC/DC converter. One illustrative terminal connection is shown in Fig. 3b and Fig. 3c, where two independent circuits are formed, terminated at C1 C1T1 and C1 C1T2, C1 C2T1 and C1 C2T2 respectively. In practice, if more currents are needed to flow through the set-S conductors, then each side may have more than one wall. By doing, more independent circuits are formed, each of which is powered by a separate AC/DC converter.

[00106] To save the cost, one may use the interleaved magnetic structure along the movement direction of a passage as shown in Fig. 3d, where one layer is permeable material while the neighbouring layer is non- permeable.

[00107] Plates 240 made of permeable material such as silicon-iron or steel are shown in Fig. 4a. Such multiple permeable plates extend the whole passage linking the low platform and high platform. They are covered by anti-friction layer for land applications. For sea/river, anti-erosion protection is also needed. They need be fixed well as they experience electromagnetic force produced by the current flowing through the set-R conductors.

[00108] The set-R conductors 250 placed between two neighbouring permeable plates, perpendicular to the walls which hold the set-S conductors, are also shown in Fig. 4a. There needs insulation around the set-R conductors. There are spaces between each column of the set-R conductors and two neighbouring permeable plates. This is to facilitate the movement of the set- R conductors along the passage. The set-R conductors could be ci rcular i n shape or rectangular in shape. The rectangular shape is more preferable as it can take the force more uniformly. They are connected in series and/or in parallel through conductor conduit 241, bundle conduit 242 and 243 in Fig. 4c, which can be dismounted from and mounted onto any container, and are shared by all the containers. The bundle conduit 242 and 243 are placed inside the enclosure 244. Such arrangement formed by 241, 242, 243, and 244 must be mechanically strong since the electromagnetic force acting on the set-R conductors is passed to them The conductor conduit 241 could be extended in both vertical directions as shown in Fig. 4d. This allows more reinforcement to make it strong enough to bear the electromagnetic force.

[00109] To increase the induced voltage in the set-R conductors, the set-R conductors should be connected in a combination of series and parallel. One example is shown in Fig. 4b, where connection parts are split equally on the two sides of the permeable plates 240. The terminals C1T1 and C1T2, C2T1 and C2T2 are connected to the box of cable connectors 245 as shown in Fig. 4d, where the cable system as shown in Fig. 14 will be joined with these terminals for DC current flowing. The detailed connection part for joining conductors in series and/or parallel is shown in Fig. 4c, where those conductors for series and/or parallel connections are connected to conductor conduit 241, which then join in bundle conduit 242 and 243. This is because to achieve the certain energy storage, the heavy mass to be shifted must weigh enough. The electromagnetic force required to balance the weight of the heavy mass in the container is very high. Hence the required number of set-R conductor is large. Then the cost of such conductors is very high. To reduce the cost, all the containers will share the same set-R conductors 250 and their fixtures and insulations, conductor conduit 241, bundle conduits 242 and 243 installed in the enclosure 244, cable connectors 245, two joining parts 247, and bearings 248, and other mechanic strengthening parts to join all these parts together as shown in Fig. 4d and Fig. 4e. Such integrated system which is to lift up or lower down all the containers is named as the integral body A. It is dismounted from one container after it reaches the targeted end of a vertical or nearly vertical passage, then moved along the supporting poles to next container which is ready to be shifted and mounted on it.

[00110] Another way for such mounting and dismounting of the container with heavy mass is shown in Fig. 5b and Fig. 5d. It has bearing coupling with the vertical supporting poles, along which it moves. [00111] In a vertical passage for lifting up the container to store energy, each time after the integral body A, which is moved with the container, reaches the top of a passage either 300 or 390 in Fig. 9a, it is dismounted from the container. After the container is moved out of the passage to the high platform, the integral body A is lowered down along the supporting poles 200 and 201 to lift up next container. A sub-system which is formed by the integral body A, the supporting poles, the first sets of conductor, and converters system works in re-generative mode to release its potential energy when it is lowered down, and to feed the generated electricity to AC grid through the AC/DC/DC converter 400 in Fig. 13. This one-round movement of the integral body A only results in copper losses, friction losses. There is no waste of potential energy or electricity.

[00112] In a vertical passage for lowering down the container to generate electricity, each time after one container with the integral body A is lowered down to the low end of the vertical passage, the integral body A needs to be dismounted and lifted up to the next container at the top of the passage and mounted on it. In this case, the i ntegral body A works i n motori ng mode when it is lifted from the bottom to the top of the vertical passage. It consumes some energy from AC grid via AC/DC/DC converter 400 as shown in Fig. 12. This one-round movement of the integral body A only results in copper losses, friction losses. This is because when the integral body A is lowered down through the passage with the container, its stored potential energy is converted into electricity fed into the power system Such amount of electricity will be consumed when moving the integral body A from the bottom to the top of the passage to fetch next container. By doing so, there is no waste of potential energy or electricity.

[00113] Certainly to facilitate such sharing of common integral body among all the containers to be moved along one passage, solid device for joining the integral body with the container is essential. This is to ensure that the combined system can move smoothly along the vertical passage guided by the supporting poles.

[00114] Figure 5a shows part of the system with the set-S conductors, and illustrative several set-R conductors in parallel and DC power supplies to the two sets of conductors.

[00115] For a practical application, one may use the above-described machine system with its controller to move the container with heavy mass along the side of a mountain or sea/river side between its bank and the sea/river bed with a steep slope. Such system is slightly modified from a vertical system by introducing a skew angle, one example design being shown in Fig. 5b (side view), and Fig. 5c (top view), where alpha is an angle of the si ope of a mountain or sea/river side between its bank and sea/river bed. In Fig. 5b, one can see that the multiple permeable plates extend from the bottom of a passage to the top of the passage linking low and high platforms. The system contains three supporting or guiding poles 201, 202 and 203 as seen in Fig. 5c. There are a number of protruding parts 206 in Fig. 5b and Fig. 5c along the passage between the high and low platforms located at the top and bottom of the mountain or sea/river. Such protruding parts are joined solidly with the two supporting poles 202 and 203 at different locations. They are for installing the supporting poles 202 and 203 onto the slope of the steep mountain or sea/river side between its bank and sea/river bed. There are also multiple interconnecting parts 204 between two supporting poles 202 and 203 at different points along the poles. Such structure formed by two supporting or guiding poles 202 and 203, and multiple 204 is very much similar to a railway track.

[00116] The bearing system 248 as shown in Fig. 5b, and Fig. 5d is three-sided for all three supporting poles 201, 202 and 203. Similar bearing system is shown in Fig. 2b, but with four- sided bearings. Such bearing system could become part of the integral body A as well, which is integrated with supporting poles and moves along them The cut cross section view of one such integral body A is shown in Fig. 5d, which contains all the set-R conductors, their terminal connections placed in conductor conduit 241, enclosure 244 which holds bundle conduits 242 and 243, terminal box 245 for joining the terminals of the set-R conductors with cables which link to converter circuits, the bearing systems 248, and mechanical strengthening parts for joining all these together. The integral body A is shared by all the containers and can move along the supporting poles working in either motoring or generating mode with magnetic field produced by the DC currents flowing through the set-S conductors. Furthermore a fastening mechanic system is installed on the integral body A to fix the container for its movement between low and high platforms along the skew passage.

[00117] The method for the container to exit from or enter into the passage for the movement along the slope of a mountain or a slope of a sea/river side is similar to that for the vertical passage. For the case of skew system, a transition mechanism from skew to vertical position of the container needs be adopted. This is for facilitating the container entering into and exiting from the passage. As the skew angle alpha is very close to 90 degrees, such transition can be made smoothly.

[00118] Compared with the design of the vertical system, the working mechanism of the skew system is close, but with more friction along the tracks. The main advantage of the skew system is that it is easier and cheaper to construct It can be built on the side surface of a mountain or side of a sea/river between its bank and bed.

[00119] The passage for moving the container with heavy mass between the high and low platforms along the slope of a mountain or sea/river side may contain multiple segments, each of which may have different angles of alpha. The angle could be less than or equal to 90 degrees. For the passage segments with the angle being equal to 90 degrees, container system just moves vertically either on land or under the sea/river. For the passage segments with the angle being less than yet close to 90 degrees, the system just moves with the support of guiding poles, and along the surface of the mountain or along the sea/river side between its bank and bed. No matter it is the vertical segment or skewed segment, the two walls formed by the set-S conductors are arranged in parallel with the supporting or guiding poles.

[00120] For the application of the heavy mass storage system to sea/river, pyramid structures need be i nstal I ed on the top and bottom of the contai ner system to pave the way for its movement along the passage with reduced friction and other losses incurred by the water. The pyramid structures need be integrated with the existing integral body A to move along the supporting poles to pick up next container after finishing delivering one.

[00121] Also for the application of the heavy mass storage system to sea/river, a huge floating artificial island or platform with positioning poles or a series of isles or small islands with positioning poles could be built on the surface of the sea/river. The containers could be draped or hung onto the floating islands at both high and low parking platforms. On the artificial islands, social activities, tourism could be arranged to alleviate the cost for building such energy storage system Furthermore wind farms and solar farms, even tidal energy farms are built to harness renewable energy. The extra energy is stored in the heavy mass energy storage system. In the long run, on-sea habitable small cities could be built with such energy management system Nevertheless environment friendly policies must be in place for such applications. To reduce the burden on the floating island, one may adopt the pole-bar grid system in sea/river. By doing so, some contai ners wi 11 be sitti ng on the bars i n the pol e-bar gri d system

[00122] Figure 6 shows the horizontal cut cross-section of the second possible structure of the system with three supporting poles, in which the concrete shell in rectangular shape, made of steel or other rigid materials reinforced concrete is also shown.

[00123] Figure 7a shows the horizontal cut cross-section of the third possible structure of the systems with two supporting poles, and two first sets of conductor, and a set-R conductors, two nearly-closed magnetic paths, and two rows of the set-R conductors ^" terminal connection. Such design is more expensive because it uses more permeable materials to form the two nearly-closed magnetic paths spanning the whole passage linking high and low platforms. Nevertheless it can reduce the demand on currents in the set-S conductors. To save the cost, one may choose the cheaper yet permeable materials to form the nearly-closed magnetic paths. One can see from Fig. 7a that a single air gap occupied by one column of the set-R conductors is g _c . There are multiple identical air gaps occupied by multiple of columns of the set-R conductors. When designing two nearly closed magnetic paths as shown in Fig. 7a, the air gap gi should be several times greater than the total air gaps occupied by the all the columns of the set-R conductors. By doing so, the magnetic flux established by the DC currents flowing through the two set-S conductors are forced to enter the area formed by the magnetic plates and the set-R conductors. In Fig. 7a, there are also other air gaps which allow connection of mechanic parts 641 with other parts in the integral body. Such mechanic parts can be extended vertically along the direction of supporting poles to gain greater mechanic strength. The air gaps gi between two nearly closed magnetic paths also need be used to enhance mechanic strength for the integral body. Hence it should be wide enough. In Fig. 7a, one can see that there are two connections 542 for joining 247 with the set-R conductors. The mechanic joining part 542 spans along the direction of the supporting poles as long as necessary to have enough mechanic strength. If the mechanic strength provided by two 642 is strong enough, then two mechanic parts 541 may not be necessary. By doing so, the total air gap in the nearly closed magnetic paths is reduced. Hence the ampere-turns demand on the set-S conductors is also reduced.

[00124] For the configurations with nearly-closed magnetic paths, in order to facilitate the series connections of the set-R conductors, small air gaps occupied by the mechanic strengthening parts 541 in Fig. 7a may still be adopted. For such applications, both the conductor conduit 241 and mechanical strengthening parts 641 can be accommodated in the air gaps by spanning vertically to have more space. Terminal connections of the set-R conductors as shown in Fig. 4c, Fig. 4d, Fig. 5b, Fig. 5c, and Fig. 5d are adopted in this configuration. Then two terminals 245, the same as that shown in Fig. 5c will be joining the cable systems as shown in Fig. 14. Such configuration with both mechanical strengthening parts 541 and conductor conduits 241 passing through air gaps is also applicable to those in Fig. 7b and Fig. 8a.

[00125] Figure 7b shows the horizontal cut cross-section of the modified third possible structure of the system, which is for steep slope application.

[00126] For such configurations as shown in Fig. 7a and Fig. 7b where there are nearly closed magnetic paths, all the set-R conductors are divided into a certain number of groups. In each group, all the conductors are connected in parallel. The two terminals of the each parallel circuit join two plate rows of the conductors ^" termination connection 551 and 552, each of which is connected with the cable system as shown in Fig. 14. At the converter side positioned at one platform, these parallel circuits will either join in series or directly to be powered by the converters. 551 and 552 are in plate shape. At the top of them, terminals of the each of the parallel circuit from the set-R conductors are placed, which are for joining the cable system as shown in Fig. 14. These plate rows not only serve as terminal connections of the set-R conductors, they also serve as mechanical strengthening parts as part of the integral body. They join solidly with the set-R conductors, then with other parts of the integral body through 641 and 642.

[00127] Figure 7c shows a part of the half of magnetic paths in Fig. 7b, which spans from the top to the bottom of a passage linking low and high platforms.

[00128] Figure 7d shows the configuration similar to that in Fig. 7b but with no air gaps formed by 641. For such configuration, less ampere-turns are required from the set-S conductors. In this case, two plate rows of the conductors ^" termination connection 651 and 652, two 642, one being each side, all the set-R conductors are solidly connected and join with other part 247 and bearings of the integral body. [00129] The configurations in Fig. 1 b and Fig. 6 only have permeable plates and the magnetic paths are not closed. For such systems, very high ampere-turns are required from the set-S conductors embedded in the walls.

[00130] Figure 7g shows another possible arrangement with only one nearly-closed magnetic path. The permeable magnetic materials in this configuration also spans from the bottom to the top of a passage. The same as that in Fig. 7a, Fig. 7b and Fig. 7d, all the set-R conductors are divided into a certain number of groups. In each group, all the conductors are connected in parallel. Two terminals of the each parallel circuit join the top of two plate rows of the conductors ^" termination connection 651 and 652, each of which is connected with the cable system as shown in Fig. 14. At the converter side positioned at one platform, these parallel circuits will either join in series or directly to be powered by the converters. 651 and 652 are in plate shape. These plate rows not only serve as terminal connections of the set-R conductors, they also serve as mechanical strengthening parts as part of the integral body. They join solidly with the set-R conductors, then with other parts of the integral body through 641 and 642.

[00131] The mechanic supports 642 in Fig. 7b and Fig. 7d need be wide enough to provide sufficient mechanical strength.

[00132] Instead of using magnetic plates spreading from the top to the bottom of a passage as shown in Fig. 3a, one may just use a magnetic- plates structure as shown in Fig. 7e or Fig. 7f for the non- interleaved structure, which has nearly the same span along the movement direction as the set-R conductors and is combined as a part of the moveable integral body. In this case, only small amount of permeable material is used for each magnetic plate 240, which moves together with the set-R conductor and other parts in the integral body. Nevertheless other magnetic material parts of each of the nearly closed magnetic path as shown in Fig. 7d still need to spread from the top to the bottom of a passage. Compared to the structure in Fig. 7e, the one in Fig. 7f can effectively reduce the demand on ampere-turns by the set-S conductors. In such a structure, all the conductors in set-R are divided into multiple groups, each group contain the same number of conductors which are connected in parallel. All the groups are connected in series to increase the induced voltage. An example connection is also shown in Fig 7e, where there are three groups of set-R conductors, and parallel connections at one terminal are shown, and then are joined to another terminal through the terminal connection box 801 which sits at the top or installed at the bottom of the magnetic plates. By doing so, the series connections of each group can be facilitated. The whole system in Fig. 7e or Fig. 7f is integrated seamlessly and mechanically with the mechanic connection 542 and 247 as shown in Fig. 7d. Although there are only four conductors in each row in structure in Fig. 7e, in practice, there could be as many as number of conductors in a row in order to produce enough uplifting electromagnetic force to lift the container with heavy mass. Moreover, the mechanic support 642 must be wide enough to provide sufficient mechanic strength to lift the heavy mass.

[00133] Figure 7g shows another possible configuration with only one nearly-closed magnetic path and one set-S conductors. In such configuration, only the structure in Fig. 7e or Fig. 7f can be used and interleaved structure as shown in Fig. 3d cannot be used.

[00134] Hence, instead of using magnetic plates spreading from the top to the bottom of the passage as shown in Fig. 3a, the structure as shown in Fig. 7e or Fig. 7f can be applied to the system as shown in Fig. 7a, Fig. 7b, Fig. 7d and Fig. 7g. For such kind of configurations, the currents in both first set and set-R conductors are constant DC ones. They flow in such a way that the electromagnetic force is upward to balance the weight of the heavy mass.

[00135] Fig. 7h shows the arrangement of part of set-R conductors in the interleaved configuration, where the conductors are insulated and embedded in the magnetic material such as steel to increase both mechanic strength and magnetic coupling effect. The other non-permeable mechanic support is also included. The shape of the conductors could be elliptical or polygon or other ones which are conducive to the magnetic coupling effect by the ampere-turns in the set-S conductors. The spreading of the magnetic materials embedding the set-R conductors along the movement direction needs be sufficient long in order to produce effective flux density experienced by the moving set-R conductors. Furthermore to meet the mechanic strength requirement for lifting up the heavy mass, the width of the embedding magnetic material as shown in Fig. 7h can be increased. Such embedding magnetic materials are only adopted for conductors between magnetic plates for passing Y -bar conductors and air gaps (e.g. in Fig. 8g) for passing the X-bar conductors in Fig. 8c or Fig. 8e or Fig. 8I. Those conductor parts for joining Y -bar conductors with X-bar conductors cannot have such embedding magnetic materials. But they still need mechanic reinforcement to have mechanic strength to lift up the heavy mass. For simplicity of drawing, simplified conductors without embedding magnetic materials in the interleaved structure are used in Fig. 8b and Fig. 8c and other figures.

[00136] As shown in Fig. 3d, interleaved structure uses less magnetic materials. Hence such structure is cheaper than that which nearly all uses magnetic material from bottom to top of the passage, except moveable part as shown in Fig. 7e or Fig. 7f etc. The non-magnetic layer in the structure as shown in Fig. 3d can be four- corner poles ^" support or other strong- enough support instead of solid one. Fig. 8a shows the top view of such interleaved structure, where every part of the nearly closed magnetic paths is interleaved, not only for the plates ^" parts. Fig. 8b illustrates part of the half of interleaved structure with the nearly-closed magnetic paths in Fig. 8a, where permeable materials such as steel or silicon iron and non-permeable materials are alternately used. Figure 8b only shows part of the nearly-closed magnetic paths with part of the set-R conductors. The gap for mechanical strength reinforcement is introduced in the middle of the structure. Between each layer of set-R conductors, mechanical reinforcement needs also be used as shown in Fig. 7h.

[00137] To make the interleaved system work, the set-R conductors needs to contain two subsets, named as set-R-subset-1 and set-R-subset-2 as shown in Figs. 8c. The height of permeable layer and non- permeable layer is the same, and equal to h. The subset- 1 and subset-2 conductors are arranged in such a way that when the layers of subset- 1 conductors enter the transition point between permeable and non-permeable layers, the layers of subset-2 conductors just cross the middle of a layer, either permeable or non-permeable layer. Such arrangement is shown in Fig. 8c.

[00138] The set-R-subset-2 conductors may have fewer layers compared with set-R-subset-1 and it needs to accommodate a pulse current with several times higher magnitude as the current flowing through set-R-subset-1 conductors.

[00139] Alternately the lifting electromagnetic force is produced by X-bar conductors and Y -bar conductors as shown in Fig. 8c, each one being upward pointing. Assume that the number of Y - bar conductors in parallel is n1. The current flowing through the X -bar conductor is the addition of the currents through all the n1 identical Y -bar conductors which are connected in parallel. Correspondingly, the cross sectional area of the X-bar conductors is n1 times the cross sectional area of each Y -bar conductor. For the same cross sectional area, there could be multiple combinations of length and width. Here length is the dimension of the conductor along the movement direction of the system and the width is the air gap distance in Fig. 8g. In this case, a proper choice of these two dimensions is essential in order to minimize the air gap the X- bar conductor passes through without compromising the smooth transition between layers for the set-R -subset- 1 conductors and set-R-subset-2 conductors. For example, if each Y -bar conductor has a cross sectional area of 1 cm X 1 cm, which can accommodate roughly 250A current to flow and there are twenty such Y -bar conductors i n paral I el, then the cross secti onal area of the X -bar conductor is 20cm ² . Assume that the height of the alternating magnetic and non-magnetic materials h is 25cm If one sets the length of the conductors equal to 5cm, then transition between layers for the set-R-subset-1 conductors and set-R-subset-2 conductors to produce upward lifting electromagnetic force is smooth. The air-gap is then 4cm. Instead, if one chooses 10cm to be the length of X- bar conductor, though the air-gap is reduced to 2cm, the transition becomes difficult and could experience problems. Such design also needs to consider the mechanic strength requirements in order to lift the container with heavy mass.

[00140] The method to operate the system is to change the currents ^" direction in the set-R conductors while the currents in the set-S conductors are kept as DC ones or constant and their directions are fixed as shown at the top of Fig. 8d. The set-R-subset-1 conductors are connected with a converter circuit to produce independent controllable close-square AC source as shown in the middle of Fig. 8d. The set-R-subset-2 conductors are connected with a converter circuit to produce independent controllable pulse AC source as shown at the bottom of Fig. 8d. The purpose of the set-R-subset-2 conductors is to facilitate the transition of the set-R-subset-1 conductors between magnetic and non- magnetic layers by generating enough lifting electromagnetic force to balance heavy mass weight.

[00141] In order to facilitate the generation of alternating currents in both set-R-subset-1 and set- R-subset-2 conductors by the converter circuits, precision position sensors are installed to detect the position of moving conductors in set-R against permeable and non-permeable layers.

[00142] Each AC source connected to each of set-R-subset-1 conductors and set-R-subset-2 conductors is either bi-directional AC/AC converter or bi-directional DC/AC converter.

[00143] Figure 8e shows another possible arrangement of part of the top-view interleaved structure, where mechanic supports 701 and 702 integrated with the set-R conductors are also shown. Figure 8f illustrates the mechanic supports and the set-R conductors while Fig. 8g shows the top-view of the interleaved magnetic structure. Figure 8h is the cross sectional view from cross section A 1A2 as shown in Fig. 8e, where the mechanic supports 701, 702, 703 are shown. Figure 8i is the cross sectional view from the cross section B1 B2 as shown in Fig. 8e, where the mechanic supports 701, 702, 704 are shown. Figure 8j is the cross sectional view from the cross section C1C2 as shown in Fig. 8e, where the mechanic supports 701, 702, 705 are shown. Figure 8k is the cross sectional view from the cross section D1 D2 or E 1 E2 as shown in Fig. 8e, where the mechanic supports 706, 707, 708 are shown. Figures 8h, 8i and 8j include parts of the view of the set-R conductors as well. They need to be well insulated from the mechanic supports, such as 703, 704 and 705 etc.

[00144] Figure 8I illustrates the arrangements of two sets of conductor in the second set for the magnetic structure in Fig. 8e. Same as those in Fig. 8c, the set-R -subset- 1 and set-R-subset-2 conductors are arranged in such a way that when the layers of set-R-subset-1 conductors enter the transition point between permeable and non-permeable layers, the layers of set-R-subset-2 conductors just cross the middle of a layer, either permeable or non-permeable layer.

[00145] In Fig. 8f, one can see that there are two pairs of the set-S conductors pair-1A, pair-1 B and pair-2A, pair-2B, in each of which DC currents flow. Their directions need to be coordinated with the AC currents in the set-R conductors in such a way that upward lifting electromagnetic forces need be produced to counterbalance the weight of the heavy mass.

[00146] Figure 8m shows another possible arrangement of interleaved structure, which is for producing greater uplifting electromagnetic force to lift heavier mass. Figure 8n shows the mechanic supports, three pairs of set-S conductors, 11 OA, 111A, and 112A, 113A, and 110B, 111 B and two sets of set-R conductors 250A, 250B. The currents flowing through each pair of first set conductors need be coordinated with the AC currents in the two sets of set-R conductors in order to produce uplifting electromagnetic forces. Figure 8o shows the top-view of the interleaved magnetic structure for the structure in Fig. 8m.

[00147] Alternating magnetic and non-magnetic structure or interleaved structure could be adopted for other machines for lifting the heavy mass to achieve energy storage.

[00148] One may choose not to use the magnetic plates in Fig. 1 b, Fig. 3a, Fig. 4a, Fig. 4b, Fig. 4c, Fig. 4d, Fig. 5b, Fig. 5c, and Fig. 6. Compared with the nearly-closed magnetic path configurations as shown in Fig. 7a, Fig. 7b, Fig. 7d, Fig. 7f, Fig. 8a, Fig. 8e, and Fig. 8m, such air-cored configurations have much higher current demand in the set-S conductors in order to establish the same level of flux density experienced by the set-R conductors.

[00149] Compared with the termination connections in Fig. 4c, the terminal connections of the set-R conductors in Fig. 7b, Fig. 7d, Fig. 7g, Fig. 8a, and Fig. 8e is relatively simple. This is because all those groups, each being with a certain number of conductors in parallel are connected in series. Their two terminals are to join with the electric cables as shown in Fig. 14 then with stationary converters.

[00150] The arrangement of set-S and set-R conductors shown in Fig. 8e and Fig. 8m can be adopted for the air-cored heavy mass energy storage system, in which there are no magnetic materials used and set-R conductors are part of the integral body.

[00151] In practice, one may design more than one integral body along one passage. At one time, two or more integral bodies lift two or more containers to either move up or move down along the same passage.

[00152] Figure 9a shows one possible structure of energy storage system with two parking platforms 330 and 350, and two vertical passages 300 and 390, from each of which the containers are lifted up or lowered down.

[00153] Figure 9b shows mechanism of shifting the containers at each platform, which includes the first sets of horizontal movers 310 and 320, the second set of horizontal movers 340 and 360, the first sets being for receiving the container from the second set of horizontal mover, then parking it to each track on the platform, or for moving the parked container from each parking track to the second set of horizontal mover; the second set of horizontal mover being for shifting the container from the exit of the passage 300 in Fig. 9a to the first set of horizontal mover, or for shifting the container from the first set of horizontal mover, then moving the container horizontally to the entrance of the exiting passage 390 in Fig. 9a.

[00154] Figure 9c show details of the first set of horizontal mover, containing rail 313 where the container may sit, push-pull locomotive 312, two horizontal tracks 311, on which the rail with the container may sit and along which the rail is pushed or pulled to be aligned either with the second set of horizontal mover or aligned with tracks on the platform. [00155] Figure 9d shows details of the second set of horizontal mover, containing two horizontal tracks 341, rail 343 where the container sits, push-pull locomotive 342; the two horizontal tracks 341 are made shift-able horizontally to bridge the exit of the passage-1 300 in Fig. 9a for receiving the container which reaches at the exit from the uplifting passage or for bridging the entrance of the exiting passage like passage-2 390 in Fig. 9a to lower down the container.

[00156] One passage or more passages 300 formed by steel -reinforced concrete shell or pole-bar system in Fig. 9a for accommodating two walls with embedded set-S conductors 110 and 111 as shown Fig. 3a, supporting poles 200 and 201 as shown in Fig. 2a and allowing uplifting the containers could be built.

[00157] Figure 10 shows the vertical cross section view of the structure with two passages and two platforms of the structure in Fig. 9a, where a slope with angle theta is shown. In practice, theta angle is properly chosen to balance between the friction losses due to shift of the container on each parking platform and the potential energy loss due to the difference of H1 and H2.

[00158] A structure with both multi-layers of high and low platforms is shown in Fig. 11, which contain more than one uplifting passages, and also more than one lowering-down passages, and is for storing more energy. Supporting mechanics between multi-layers of the high platforms and between multi- layers of the low- layer platforms need be adopted.

[00159] For a heavy mass energy storage system built along the slope of a mountain /mound, river/sea sides, multiple tracks can be built instead of vertical passages as shown in Fig. 9a, Fig. 10 and Fig. 11. To reduce the friction losses for the movement of containers on either high or low platforms, ancillary system could be built. For example, for the river/sea side application, floating buoy could be used to provide lifting-up force when the container is moved along the platforms. For the land application, similar lifting-up force such as by magnetic levitation system could be produced to reduce the friction losses during the movement of the containers on the platforms. By doing so, slope of the platforms may or may not be necessary.

[00160] A first set of AC/DC converter circuit 410 is shown in Fig. 12 and Fig. 13 to power the set-S conductors 110 and 111 embedded in the walls. As the set-S conductors may contain multiple layers or walls, each of which could be powered by one separate AC/DC converter. By doing so, back-up magnetic field generation could be produced. Certainly AC-DC-AC-AC-DC converters with medium-frequency or high-frequency transformer isolation could be also adopted to produce larger current in the set-S conductors. The main function of these converters is to produce constant currents flowing through the set-S conductors. By doing so, a unidirectional DC magnetic field is produced in the region between two walls.

[00161] Ri and L i in Fig. 12 and Fig. 13 are the equivalent copper resistance and inductance of the set-S conductors, while R ₂ and L ₂ are the equivalent copper resistance and inductance of the set-R conductors.

[00162] A second set of AC/DC/DC converter circuits 400 is also shown in Fig. 12 and Fig. 13 to power each individual circuit formed by the set-R conductors mounted on the integral body A.

[00163] The circuits in Fig. 12 work in the motoring mode when the container is moved from low platform to high platform, while the circuits in Fig. 13 work in the generating mode when the container is moved from high platform to low platform.

[00164] Figure 14 shows the power supply to the set-R conductors mounted on each container. As the converter circuits are also costly, in this design, all containers being uplifted through the passage 300 share the same set of AC/DC/DC converters installed at one platform The connection cables between the output of these converters and terminals of the set-R conductors mounted on the integral body A are also shown in Fig. 14. They are hung through two pulleys. All the containers being lowered down through the passage 390 share another set of AC/DC/DC converters installed at one platform. In practice, the sliding contact between terminals of the set- R conductors and the cables linking to converters in Fig. 14 is possible.

[00165] The container system with all the items which is moved vertically along the passage 300 or 390 in Fig. 9a should be arranged properly in terms of gravity center. The mass in the whole system should be distributed in such a way that minimum friction between bearings and the supporting poles is achieved under the action of both weight of the system and lifting electromagnetic force on the set-R conductors. When designing the integral body A, such approach also needs be taken to ensure that minimum friction between bearings and the supporting poles is achieved.

[00166] To move the container more smoothly, a third set of conductors could be installed at on the container. Such third set of conductors may be divided into several groups, each being installed at different locations in the container, and each being powered by a separate group of converter circuits, each of which is controllable by a separate AC/DC/DC converter 2 in the same way as shown in Fig. 14. Pressure sensors could be installed along the supporting poles to sense the pressure imposed by the container on the supporting poles. Such sensed pressure could be used as input to control the AC/DC/DC converters to produce different levels of currents in each group of the third set of conductors.

[00167] The total conductors in set-R are divided into a number of groups. Conductors in each group could be connected in parallel. All the groups are connected in series then powered by one AC/DC/DC converter-2 400 as shown in Fig. 16a. This is not very practical as the total demanded current could un- realistically high. Furthermore parallel connection has unpredictable side effect The applied voltage to each of the conductors in parallel is the same. The induced voltage across each conductor is almost the same. If there is a small variation of the conductor resistance between any two conductors in parallel, then the currents shared by them are different This could lead to serious conductor overheating issue. Nevertheless if one can ensure minimum difference in the resistance of the conductors, they can be connected in parallel to reduce joining parts due to series connection.

[00168] In a more practical way, all the conductors in each group could be connected in series to form each individual circuit and then powered by a separate AC/DC/DC converter-2 400 as shown in Fig. 16a. The two terminals of each circuit formed by each group of conductors are connected with two terminals from each AC/DC/DC converter-2 400 through the cable system through pulleys as shown in Fig. 14. Such AC power to DC power converters convert power from AC microgrid/grid when moving the container from low platform to high platform. By doing so, surplus electric energy from grid/mi crogrid is converted into potential energy stored in the heavy mass. V ice versa, when the container is lowered down from high platform to low platform, such converters are to feed power back to the AC grid/mi crogrid due to the reduced potential energy stored in the heavy mass. Such AC power to DC power converter can also be AC-DC-AC-AC-DC converters with medium-frequency or high-frequency transformer isolation. These converters must be bi-directional to facilitate both motoring and generating modes of operation.

[00169] When such energy storage system is used with DC microgrid, then DC/DC converters are adopted for both the set-S conductors and the set-R conductors. [00170] Mechanic braking mechanism is installed at the bottom of the container to allow emergency braking along the supporting poles when moving along the passage vertically. This may become necessary when the power supply or converters etc become faulty.

[00171] Multiple containers can be moved either up or down simultaneously. So long there are multiple sets of second converters 400 installed at station as in Fig. 14.

[00172] To reduce the loss due to friction in the horizontal platforms, one may use downward slope platforms 330 and 350 as shown in Fig. 9a instead. By doing so, driving force and frictions for moving the container from passage- 1 300 to passage-2 390 along the platform 330 is reduced. This comes with the sacrifice on the reduction of overall efficiency. If H2 is only 95% of H1, there will be 5% energy loss only due to the difference between H1 and H2. This loss may be worthwhile if friction incurred in conventional horizontal movement of the very heavy containers along the rails on the parking platform results in more loss.

[00173] For relatively small-scale energy storage, only one vertical passage could be adopted for both uplifting and lowering-down of the container. In that case, the parking platform should be on a horizontal plane.

[00174] In Fig. 9a, both low and high platforms 330 and 350 built along a slope are formed by multiple tracks for parking the containers.

[00175] Another approach to form parking platforms is to adopt a pole- bar system. Such system may be suitable for the area close to dense population. In this case, the high platforms are formed by the bars installed with the vertical poles. The containers just sit on two neighbouring bars in parallel.

Working mechanism

[00176] When the container is to be lifted upward from low platform to high platform, the whole system works as a DC motor, seen from the inputs of the set-S conductors and the set-R conductors. The upward-moving set-R conductors cut the magnetic field produced by the currents flowing through the set-S conductors, leading to counteracting back electromotive force (E M F). The circuit diagram is shown in Fig. 12. In this case, DC power provided from the AC/DC/DC converter-2 400 in Fig. 12 is absorbed by the back electromotive force (E M F) E ±M. Such electric energy is converted into heavy mass potential energy of the container which is lifted up from low platform to high platform

[00177] When the container is to be lowered down from high platform to low platform, the whole system works as a DC generator, seen from the inputs of the set-S conductors and the set- R conductors. The downward- moving set-R conductors cut the magnetic field produced by the currents flowing through the set-S conductors, leading to an induced E M F E dcc The circuit diagram is shown in Fig. 13. The AC/DC/DC converter-2 400 still forces the circuit to produce the same direction current along the set-R conductors. The magnetic field and flux established by the currents in the set-S conductors are still in the same direction. But movement of the set-R conductors is opposite or in downward direction. Hence the polarities of induced E MF are reversed compared with that in the upward movement. Then the induced E M F produces a current in the same direction along the set-R conductors. Hence the system works as generator and generates power. By doing so, the reduced potential energy stored in the container is converted into electricity energy, fed back to microgrid or grid. With the same direction currents in the set- R conductors, the electromagnetic force is still in upward direction in order to balance overall weight of the container system Although the current flowing direction is the same in the set-R conductors, the currents flowing through AC/DC/DC converters 400 reverses their directions in each of the circuit in Fig. 16a. This is to facilitate feeding power back into microgrid/grid through AC/DC converter 402 in Fig. 17. To facilitating the operation in this generating mode, each of the switches SW21, SW22 etc in Fig. 16a needs to change their positions to achieve the connections in Fig. 17b.

Design of the system

[00178] Below is a simplified method for designing a heavy mass energy storage system with vertical or nearly vertical movement Such method can be modified to suit the design of the system with skew movement along a steep slope. For a systematic design, one may use commercial software such as MAXWE L L 3D from ANSY S company to carry out electromagnetic analysis, and use other commercial software to carry out mechanic, fluid- dynamic or aero-dynamic, thermal and other analysis. [00179] Figure 15a shows an approximate method based on a solenoid model to calculate the magnetic field between two set-S conductors 110 and 111 embedded in the two walls as shown in Fig. 5a.

[00180] If the medium is air, then

where N1/L1 is per- meter conductors for the set-S of the conductors.

[00181] Since there are two set-S conductors embedded in the two walls placed at two sides of the permeable plates, then field and flux density in (1) are doubled.

[00182] If N1/L1 is 40, Ii=20A, Li=2m, d=1.5m, then the approximate magnetic field calculated from (1) with the consideration of a factor of 2 is 800A/m along the x-direction in Fig. 15a. Results from the exact calculation based on individual contribution by the current flowing through each conductor in the first set are shown in Fig. 15b and Fig. 15c, which have some differences from the approximate value 800A/m. Such results in Fig. 15b and Fig. 15c are useful for selecting the length of bundle conduit 243 in Fig. 4c in order to avoid significant voltage induced along the conductors in bundle conduit 242. One may also use exact calculation to arrange the set-S conductors i n order to obtai n more uni form f i el d between two wal I s.

[00183] If the medium is a permeable material with a relative permeability of m, then total flux density is as follows

[00184] Lorentz force for calculating the force experienced by a current-carrying conductor immersed in a magnetic field is expressed as follows:

[00185] For each conductor in the second set, the force is

F = I ₂ IJB IJL ₂ (4) where L ₂ is the length of each of the set-R conductors. [00186] The design target is to produce a flux density of 1.2T in the air gap where the second sets of the conductors is placed.

[00187] The force experienced by a total number N ₂ of conductors in set-R mounted on the integral body A is given by

F = N ₂ (I ₂ L ₂ B) (5)

First example design: configurations only contain permeable plates and have no nearly-closed magnetic paths

[00188] Assume that 25kWh energy is to be stored with a lift height of 100m. Then mass in kg is m = 25 ¼10 ³ ( W ) ¼3600(s) / gh = 25 ¼10 ³ /43600 / (9.81 ¼100) = 9.17 ¼10 ⁴ ( kg )

[00189] Under steady-state, the force acting on the conductors of set-R is equal to the total weight of the container 100. Hence one has

B ¼ N ₂ I ₂ L ₂ = 9.17 ¼10 ⁴ ¼9.81 (6) where the f I ux densi ty i s targeted at 1.2T , whi ch i s a real i sti c val ue for steel or si I i con- i con.

[00190] To produce a flux density of 1.2T in the permeable plates, the required ampere-turns in the set-S conductors is not high. But such flux density cannot sustain through whole span where the set-R conductors is positioned. To produce the same amount of flux density experienced by the set-R conductors, much higher ampere-turns are required.

[00191] Similar situation with a demand of high ampere-turns in the set-S conductors is true for air-cored case.

[00192] If one uses the configurations as shown in Fig. 1 b, Fig. 5c, Fig. 6 which only contain permeable plates and no nearly closed magnetic paths, then very high ampere-turns are needed from the set-S conductors embedded in two walls. In this case, instead of using two set-S conductors or one pair of the set-S conductors, one may use multiple pairs to produce so high an ampere turns.

[00193] If one uses the configurations as shown in Fig. 7a, Fig. 7b, Fig. 7d and Fig. 8a which contain nearly closed magnetic paths, then required ampere-turns from the set-S conductors embedded in two walls are lower. [00194] No matter which configuration is chosen, the target is the same: flux density experienced by the set-R conductors is around 1.2T. In a practical design, higher flux density can be targeted as some permeable materials may have as high as 1.8-2.0T saturation level.

[00195] The first set of conductor could divided into several groups, conductors in each group being connected in series as shown in Fig. 3b and 3c. The conductors in each group are connected in series to form an individual circuit Totally in the illustration, there are two independent individual circuits formed, terminated at C1C1T1 and C1C1T2, and C1C2T1 and C1C2T2 respectively. Each individual circuit is powered by one separate AC/DC converter circuit 410 as shown in Fig. 12 and Fig. 13. If the converter 410 can provide more current, individual circuits in set-S can be connected in parallel.

[00196] The following calculation is based on the configurations in Fig. 1 b, Fig. 5c, Fig. 6 which only contain permeable plates and no nearly closed magnetic paths.

[00197] If one designs the system to move the container through passage- 1 300 in Fig. 9a of 100m using one minute, then the power absorbed by E dcM in Fig. 12 needs to 25kWh/(1/60)=1.5MW. The velocity v of the container and the set-R conductors is 100m/(1*60)=1.667m/s.

[00198] The number of turns of the set-R conductors is assumed as N 2=2000;

[00199] Flux density in the air gap where the set-R conductors are placed: B=1.2T;

[00200] L.2 is assumed to be 1.5 meters;

[00201] To meet force balance requirement under steady-state movement, the following equation should be satisfied

[00202] The induced voltage in each of the set-R conductors is given by

nB\

induced = Xv¼ ) yi = vBL ₂ = 1.667¼1.2¼1.5= 3.001V (8)

[00203] Then total power transferred is 2000*3.001 *250=1.5005MW, close to 1.5MW. Therefore it is possible to design the system and operate it at states as described above to achieve its design target. [00204] If the velocity of the container is faster, then power delivered is higher and more pressure is on the converters since they need to handle more power.

[00205] In this case, if all the 2000 conductors in set-R are in parallel, then the total current demanded is 2000*250=500kA, which is formidably high. To produce this tremendously high current could pose a serious challenge. To solve this issue, one may divide all the conductors in set-R into different groups. In each group, all the conductors are connected in parallel. Different groups in set-R are connected in series. The magnetic field produced by the set-S conductors embedded in the vertical walls decays quickly beyond the region between the two walls. To avoid counteracting induced E M F in the connecting parts 242, the connections are extended beyond the region between two walls as shown in Fig. 4c. By doing so, the E MF is only induced in the conductors placed between two walls, and nearly zero E M F is induced in those connecting conductor outside the region between two walls. Since different groups of conductors in set-R are connected in series, the total E MF is increased. The placement of connection parts in the loop needs be addressed properly in order to avoid irregular interacting force between them For those connecting parts 243 within the immersion of the magnetic field produced by the current flowing through the set-S conductors embedded in the two walls, they should be placed horizontally and along the direction of the magnetic field produced by the currents flowing in the set-S conductors. By doing so, there is nearly zero force acting on these parts.

[00206] For the above design, if one divides 2000 conductors in set-R into 100 groups, each group containing 20 conductors. All the 20 conductors in each group are connected in parallel, and all the 100 groups are connected in series. Then the induced E MF can be increased from 3.001V to 3.001*100=300.1 V. The current flowing through each conductor is still 250A. Then the total current into the circuit of set-R conductors is 250A *20=5000A, which is a small fraction of 500kA, and becomes more realistic. More number of groups connected in series incurs more joining parts 242 and 243 in Fig. 4c. With less number of groups of conductors, the number of conductors in each group in parallel becomes greater and the current demanded is higher. So it is a compromise between the total current level and complexity of connections. Such parallel connection of the conductors may have a potential problem. This is because there may be a small variation of resistance in each conductor in set-R. Since the induced voltage and applied voltage are nearly the same in each conductor, a small variation of the resistance in the parallel conductors could result in significant difference of currents shared in each conductor, thereby leading to overheating issues in the overloaded conductors.

[00207] Another arrangement with less current demand on each AC/DC/DC converter 400 in Fig. 16a is to divide all conductors in set-R into many groups. The conductors in each group are connected in series. Each group is connected with a separate AC/DC+DC/DC converter circuit 400 as shown in Fig. 16a. In the example design, one may divide 2000 conductors in set-R into 25 groups, each group containing 80 conductors. All the 80 conductors are connected in series, which gives 3.001 *80=240.08V. Then 25 independent AC /DC + DC/DC converter circuits 400 as shown i n F ig. 16a are used to power each ci rcuit formed by each of the 25 groups and with the current into each group being 250 A. To reduce the current from each converter, one may increase the number of the set-R conductors.

[00208] It is possible to operate the system at even higher voltage. By doing so the current in each converter circuit is reduced. For the above design, one may divide 2000 conductors in set-R into 10 groups, each group containing 200 conductors. All the 200 conductors in each group are connected in series, which results in 3.001*200= 600.2V. Then correspondingly ten independent AC/DC + DC/DC converter circuits 400 as shown in Fig. 16a are needed, each with 250A. For even higher voltage application, 50Hz transformer can be used between three-phase source and AC/DC+DC/DC converter 400 as shown in Figs. 12, 13, 16 and 17 if the AC source voltage has a line-line voltage of 415V .

[00209] One of the functions of DC/DC converter 404 in Fig. 17 is for producing a suitable level of voltage applied to the circuitformed by each group of conductors at start-up or halt stage. This is because the induced E M F E± is zero when the container is stationary or very small value when the speed of the container is low. As it is hard to tune the output voltage of DC/DC converter 404 continuously, each circuit in Fig. 16a is inserted with a Rext, which is for limiting the currents in the circuit during start-up or halt stage. When the container gains speed, such resistance is gradually reduced to smaller value until being totally cut off from the circuits to avoid unnecessary losses. V ice versa, at halting stage, the Rext is increased from zero to gradual high value to limit the current flowing through the set-R conductors. To facilitate both motoring and generating modes of operations, switches as indicated by SW21, SW22, till SW2m in Fig. 16a are used, which could be relay based electronic switches. This is because the polarities of induced voltage E± are opposite in the motoring and generating modes as indicated in Fig. 17a and Fig. 17b.

[00210] If one wants to store energy faster, then the cost on converter circuits is higher. Hence it is a compromise between cost and how quickly energy should be stored or released. To reduce the converter cost, one set of converters can be used for moving containers upward, while another set of converters can be used for moving containers downward.

[00211] Choosing proper sizes of the conductors in both set-S and set-R is critical to keep the efficiency high. The set-S conductors could be large enough to keep the copper losses as small as possible, say less than 1-2%. This comes with higher price for the cost of the set-S conductors. The conductors ^" size of the second set should be chosen properly with the consideration of total air-gap distance, copper losses and cost of the copper conductors, mechanical strength needed. Greater sizes of the conductors result in greater air gaps and higher cost of the copper or aluminium, which demand more ampere- turns from the set-S conductors, though greater sizes result in smaller copper losses, thereby higher efficiency.

[00212] Since iron ores are weakly permeable, there should be sufficient distance between the set-S conductors and them This is to avoid movement-impeding force acting on the container system due to the magnetization of the iron ore

Second example design: configurations contain nearly-closed magnetic paths

[00213] The set-R conductors in the configurations as shown in Fig. 7a, Fig. 7b, Fig. 7d and Fig. 8a, which contain nearly closed magnetic paths, are divided into a number of groups. All the conductors in each group are connected in parallel. Two terminals of each parallel circuit join two plate rows of the set-R conductors ^" terminal connection 651 and 652 in Fig. 7a. To reduce the number of cable conductors in Fig. 14, it is necessary to have smaller number of parallel circuits. Hence for such system, it is more practical to operate it at higher speed to induce higher voltage in each parallel circuit Hence such configurations are more suitable for longer passage application.

[00214] If one designs the system to move the container through passage- 1 300 in Fig. 9a of 400m using 10 seconds, then the power absorbed by E dcM in Fig. 12 needs to 25kWh/(1/60/6)=9.0MW. The velocity v of the container and the set-R conductors is 400m/(1*10)=40nVs. For such high speed operation, the air or water paving pyramid structure installed on the top and/or bottom of the integral body is needed. By doing the losses due to friction with either air or water is reduced.

[00215] T he number of turns of the set- R conductors i s assumed as N 2=2000;

[00216] Flux density in the air gap where the set-R conductors are placed: B=1.2T;

[00217] L 2 i s sti 11 assumed to be 1.5 meters;

[00218] Assume that 25kWh energy is to be stored with a lift height of 400m. Then mass in kg is m = 25¼10 ³ (W) ¼3600(s) /gh = 25¼10 ³ ¼3600/(9.81 ¼400) = 2.29¼10 ⁴ (kg) [00219] To meet force balance requirement under steady-state movement, the foil owing equation should be satisfied 2.29¼10 ⁴ ¼9.81 2.29¼10 ⁴ ¼9.81 2.29 ¼10 ⁴ ¼9.81

I, = = = = 62.5A (9)

² B ¼N ₂ ¼L ₂ 1.2¼2000¼1.5 3600

[00220] The induced voltage in each of the set-R conductors is given by

E _d u _ced = v¼B) IJdl = vBL ₂ = 40¼1.2¼1.5 = 72V (10)

[00221] Then total power transferred is 2000*72*62.5=9.0MW. Therefore it is possible to design the system and operate it at states as descri bed above.

[00222] In this case, if one divides 2000 conductors in set-R into 10 groups, then each group contains 200 conductors. All the 200 conductors in each group are connected in parallel. The current flowing through each parallel circuit is 200*62.5= 12.5kA. To supply so high a current to each such circuit, multiple AC/DC/DC converters are connected in parallel as shown in Fig. 16b. Ten such converter circuits as shown in Fig. 16b are needed to power ten circuits formed by the ten groups of the set-R conductors. To operate DC/DC converter in Fig. 16b at higher voltage, ten groups of circuits formed by the set-R conductors at the station where the converters are positioned can be further divided into two sub-groups. Each sub-group contains 5 groups of circuits, which are connected in series. Hence the induced voltage can be increased to 5*72=360V . By doi ng so, I ess number of converters as shown i n F ig. 16b are needed.

[00223] In this second design example, many conductors out of the set-R conductors are connected in parallel. Hence one needs to ensure that each conductor in parallel has same series impedance. By doing so, the current shared by each parallel circuit is nearly the same. There is no overheating issue in such parallel connection.

Duality configuration

[00224] Besides the structure of the heavy mass energy storage system described above, in which the set-R conductors are moveable while the set-S conductors, the permeable plates and/or the other permeable parts for forming the nearly-closed magnetic paths are stationary. Compared with such first design, a second design could be adopted, which is in opposite way. That is to say that one can have a structure of a heavy mass energy storage system in which the set-R conductors are stationary, spanning from the bottom to top of a passage linking the low and high platforms while the permeable plates and/or the other permeable parts for forming nearly- closed magnetic paths are moveable with the set-S conductor wound on the permeable magnetic cores. The container with heavy mass is mounted and dismounted to the moveable magnetic parts, which are in the size scale comparable with the dimensions occupied by the set-R conductors in the first design, adopted in this invention.

C ontrol I er of the system

[00225] Figure 17 shows the circuits during both motoring and generating modes of operation, where F i g. 17a i s f or the motori ng mode whi I e F ig. 17b i s f or the generati ng mode.

[00226] Equation for motoring mode of operation is given by (11) and Equation for generating mode of operation is given by (12).

E =V _{2 +} R ₂ i _{2 +} L ₂ - (12)

[00227] Figure 18 shows simplified controllers for both motoring and generating modes of steady-state operation, where Fig. 18a is for the motoring mode while Fig. 18b is for the generating mode, and the controllers can be proportional -integral controllers or other types of controllers. In practice such controller needs be modified to consider all factors in the system, such as position of the container etc. The purpose of the controllers is to control voltage across C2 in Fig. 17 to stabi lize at a suitable value in order to generate the targeted current i2 to follow its reference.

[00228] Newton- 1 aw equation for upward movement is given by (13) while the Equation for downward movement is given by (14) with v _e i being the velocity or speed of the container movement F being the electromagnetic force acting on the set-R conductors, m being the mass of the whole container system, g being gravitational acceleration.

F - rr¾ = rrv^- (13) mg - F = m^L (14) f ^a dt

[00229] Under steady-state movement, the right- hand-sides of both (13) and (14) are zeros. For a designed system of the container, the total rrg is known. Hence the required steady-state force F is determined. From E quation (9), one can calculate the required reference current after Ii is determined. For a pre-set speed or velocity of the container system, one can use (10), the number of conductors and its connection in the set-R conductors to calculate the reference voltage E _± ^* _M and E _± ^* _G . Hence both reference currents and voltages used in the controllers as shown in Fig. 18 are determined. So long a proper controller in Fig. 18 is designed, the container can be controlled to move at the targeted speed.

[00230] During the start-up or halt, the control becomes more complicated. E quation for motoring mode of operation is given by (15) and E quation for generating mode of operation is given by (16), where the external resistance R ext plays a role. 2 = ( ₂ + _e Ji ₂ ⁺ L ₂ -^ + E _dcM (15)

E _dcG =V _{2 +} ( R _{2 +} R _e Ji _{2 +} L ₂ -½- (16)

[00231] In the motoring mode at start-up for lifting up the container from the low platform to high platform, the resistance R ext is reduced gradually from high value to low value. In the meantime, V ₂ is tuned from low value to high value with the gaining speed of the container. The reduction of Rext and increase in V ₂ need be coordinated in such a way that when the speed of container reaches its design target, V ₂ should be close to its steady-state value while the current i ₂ could be higher than its targeted steady-state value. After the speed of the container reaches its design value, steady-state control as shown in Fig. 18a takes over. In the motoring mode at halt stage for lifting up the container and when reaching the high platform, R ext is increased gradually from zero to high value. In the meantime, V ₂ is tuned from high value to low value and eventually the circuit formed by the conductors of set-R is turned off from the AC/DC/DC converters 400.

[00232] In the generating mode at start-up for lowering down the container from the high platform, the resistance R ext is reduced gradually from high value to low value. In the meantime, V ₂ is tuned from low value to high value with the gaining speed of the container. The reduction of Rext and increase in V ₂ need be coordinated in such a way that when the speed of container reaches its design one, V ₂ should be close to its steady-state value while the current i ₂ could be lower than its targeted steady-state value. After the speed of the container reaches its design speed, steady-state control as shown in Fig. 18b takes over. In the generating mode at halt stage for lowering- down the container and when reaching the bottom of the vertical passage, R ext is increased gradually from zero to high value. In the meantime, V ₂ is tuned from high value to low value and eventually the circuit formed by the conductors of set-R is turned off from the AC/DC/DC converters 400.

[00233] When the uplifted container reaches the exit of passage-1 300 at the high platform 330 in Fig. 9a, it is moved purposely slightly higher than the exit Before the power in the circuits is turned off, the second set of horizontal mover 340 is quickly shifted to bridge its two sides of the exit of the passage 300. Then the current into the set-R conductors mounted on the container is reduced gradually to zero by controlling the AC/DC/DC converter 400. In the meantime, the rail 343 is pushed in by the locomotive 342 to the exit the vertical passage 300. By doing so, the container will be sitting on the rails 343 of the second set of horizontal mover 340 in Fig. 9d. The locomotive 342 is to pull out of the rails 343 with the container sitting on it along the track 341. It then aims with the rail 313 on the first set of horizontal mover 310 in Fig. 9c. Then the container is pulled away by the locomotive 331 in Fig. 9b from the rail 343 of the second set of horizontal mover 340 and is pulled onto the rail 313 of the first set of horizontal mover 310. T hen the I ocomotive 312 sitti ng on the f i rst set of horizontal mover is to pul I or push the rai I 313 with the container sitting on it horizontally to aim at a target track on the high platform 330. Once aimed, the locomotive 331 joins in again to pull it along the designated track to park the container on it.

[00234] When lowering down the containers at the entrance of lowering-down passage such as 390 in Fig. 9a, the procedure is the opposite. The locomotive 331 on the platform pushes the container onto the rail of the first set of horizontal mover 320. In the meantime, the second set of horizontal mover 360 is shifted to bridge the entrance of the passage-2 390. Then the first set of horizontal mover 320 is pushed or pulled by its locomotive along its track to aim its rail towards the rail of the second set of horizontal mover 360. The locomotive 331 will be involved to push the container onto the rail of the second set of the horizontal mover 360 from the rail of the first set of horizontal mover 320. The locomotive sitting on the track of the second set of horizontal mover 360 pushes its rail with container sitting on it along its track to the entrance of the lowering-down passage 390. After the container is positioned and joins with the integral body A, the pole stopper 255 fastens the positioning or supporting poles 200 and 201. Then the controller of the second set of converters is to control the currents into the conductors mounted on the container to lift up the container slightly. Then the two tracks of the second set of horizontal mover 360 are shifted out of the entrance of the lowering-down passage 390 to receive the next container from the parking platform to be lowered down.

[00235] The method described above is an example control for the non- interleaved structure. In practice, it is more complicated than this. For the interleaved configuration, the method for producing the DC current flowing through the set-S conductors is still straight forward, either from AC/DC converters or from AC/DC/DC converters. But the alternating currents into each of set- R -subset- 1 and set-R-subset-2 conductors need be produced through separate AC/AC converters or AC/DC/AC converters. Proper generation of AC current in set- R -subset- 1 and set- R-subset-2 conductors for motoring and generating operation need be addressed in the interleaved structure.

[00236] The whole heavy mass energy storage disclosed herein is to be equipped with automation and communication system. Each individual part in the system is monitored by a list of mechanic, electric, thermal sensors and image sensors etc. The information such as location, velocity etc of each container, the current and voltage in each circuit, working states of each of the first sets and second sets of horizontal movers, available parking space in each parking platform is collected and transmitted to and processed by local management systems. All commands are passed to local electric and mechanic parts and executed. Also collected local information and commands are transmitted to a central management system (CMS). The whole system works in a highly automatic way, even in autonomy state with minimum interference from personnel, who only needs to input basic instruction into CMS, such as how much energy to be stored within next several hours etc. Then CMS will optimize the operation of the system to achieve such target.

Cost analysis

[00237] One useable heavy mass could be iron ore, though other heavy masses may also be used. It has a relatively higher ratio of mass density to the price and higher compactness.

[00238] Iron ore mass density =5.15X 10 ³ kg/m ³ .

[00239] If people process the raw iron ores themselves, the price could be reduced to very low.

[00240] For either permeable plates or the nearly closed magnetic paths, interleaved structure as demonstrated in Fig. 3d could be adopted to save cost. When the interleaved magnetic structure is taken, more set-R conductors need be adopted which should span longer in the vertical direction or direction along the guiding poles, in order to ensure the same electromagnetic lifting force is produced as that in non-interleaving structure.

[00241] Furthermore, in view that heavy mass storage can be used for more than twenty years, longer than battery, its initial cost will not be an obstacle to stop using it

INT E R PR ETATION In accordance with:

[00242] As described herein, :in accordance with ^" may also mean :as a function of ^" and is not necessarily limited to the integers specified in relation thereto.

Embodiments:

[00243] Reference throughout this specification to One embodiment _. , ^' an embodiment _. , ^' one arrangement _, or ^' an arrangement _, means that a particular feature, structure or characteristic described in connection with the embodiment/arrangement is included in at least one embodiment/arrangement of the present invention. Thus, appearances of the phrases Ίη one embodiment/arrangement _, or Ίη an embodiment/arrangement _, in various places throughout this specification are not necessarily all referring to the same embodiment/arrangement, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments/arrangements.

[00244] Similarly it should be appreciated that in the above description of example embodiments/arrangements of the invention, various features of the invention are sometimes grouped together in a single embodiment/arrangement figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment/arrangement Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment/arrangement of this invention.

[00245] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art For example, in the following claims, any of the claimed embodiments can be used in any combination.

Specific Details

[00246] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. Terminology

[00247] In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "forward", "rearward", "radially", "peripherally", "upwardly", "downwardly", and the like are used as words of convenience to provide reference poi nts and are not to be construed as I i miti ng terms.

Different Instances of Objects

[00248] As used herein, unless otherwise specified the use of the ordinal adjectives ^' first _. , ^' second _. , ^' third _, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

Comprising and Including:

[00249] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word ^' comprise _, or variations such as ^' comprises _, or ^' comprising _, are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[00250] Any one of the terms: ^' including _, or ^' which includes _, or ^' that includes _, as used herein is also an open term that also means ^' including at least _, the elements features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

Scope of Invention

[00251] Thus, while there has been described what are believed to be the preferred arrangements of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[00252] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

[00253] It is apparent from the above, that the arrangements described are applicable to electric power industries, more specifically to energy storage system used in power system. The heavy mass energy storage system disclosed in this invention is the most useful for large-scale energy storage, where multiple layers of high platforms and low platforms are adopted and there are also multiple uplifting passages and multiple lowering-down passages as shown in Fig. 11.

[00254] This is to facilitate building large-scale microgrids/grids which have the capability of self-sustainability and self-sufficiency in the isolated or islanded operation mode. This is also to facilitate the temporary storage of energy in remote wind farms or solar farms etc when the renewable energy generation is more than the amount to be transmitted to populated areas or industry areas, located far away from the generation and storage, and release the stored energy in the heavy mass to be converted into electricity and transmitted to end users through transmission systems.

Note for us ng this technology

[00255] Massive energy storage is one of the main obstacles to overcome in order to solve energy crisis problem faced by human-beings. If this invention turns out to be useful, then the inventor hopes reasonable invention fee or patent fee will be collected from users without putting heavy levy on them. Hence fee collection is maximally 16% of the market price of electricity generated using such kind of technology. To encourage its usage, no fee is collected in the first two years of usi ng such ki nd of energy storage system. After two years, fees wi 11 be col I ected.