The present invention generally relates multistage solar concentrated photo voltaic. More particularly, the present invention encompasses a comprehensive multistage CPV solution with continuous closed loop, feedback controlled, automated, with supervisory monitored and controlled, operating from dawn to dusk and over the complete day and year with sun sensing and tracking system, with a provision of peaking the efficiency in terms of concentration collection, generation and power transportation.

BACKGROUND OF THE INVENTION

Solar energy is in use world-wide. Both heat energy harvesting and direct conversion of solar to electrical power are known in the art. Nowadays, the significant surge in demand for alternative sources of energies (i.e., wind, solar, hydro, etc.) has created opportunities for fast development of the global alternative energy infrastructure, measurable at the giga-watts levels. The construction of new solar power plants has been intensified, leading to a subsequent boost in manufacturing and generating capacities worldwide and, thus, to significant reductions in costs with the shift towards an economy of scale and minimise the land usage. Measurable drops in the PV solar panel manufacturing and installation costs resulted in comparable reductions of the overall ^' power plant costs. However, increase in performance of the PV solar panel modules and improvements of the solar power system effectiveness through technical innovations have a more direct and stronger impact on reducing costs by allowing for a lower number of PV solar panels for a desired power output, thus a smaller footprint of the respective PV solar installation. To this end, new technological advances in the rapidly growing field of concentrated PV cells underline a genuine option for significant reductions in PV cell surface area per kW of electrical output and, therefore, a real possibility to produce electricity at competitively lower costs.

The solar light concentration for efficient solar energy harvesting is also a well-known phenomenon. Among solar electricity generation technologies, photovoltaic (PV) technologies have seen the largest growth over the last few years and PV is

i increasingly seen as a viable alternative for electricity generation. However, the efficiency of this technology has well known limitations: for direct solar irradiation on Si/CIGS PV panels, the efficiency of solar to electric energy conversion peaks at around 15%. Recently, commercially available multi-junction with efficiencies exceeding 40% has been developed. However, the price increase associated with manufacturing these cells is much higher than the efficiency increase, making these high-efficiency cells unsuitable for normal PV panels. Concentrated photovoltaic (CPV) systems provide the solution by using an optical concentrator to concentrate the sunlight using before it reaches the cell. The result is more sun Light energy hitting the PV surface thus requiring a much smaller cell for the same electrical output. The benefit of so doing is twofold: 1 ) the economy of the system is improved by replacing expensive PV cells with less expensive optical elements; 2) the efficiency of the PV cell is augmented by higher incident solar fluxes resulting from the concentration. Using the same amount of land, CPV systems can produce more electricity, more efficiently and using much less PV material than conventional PV systems. Recent studies have shown that the majority of cost for a CPV system is represented by the concentrator, its structure, and the tracking system mechanism. Therefore the greatest cost reductions can be achieved by targeting these technologies.

Notwithstanding the progress thus far achieved, the conventional technologies used for direct conversion of sunlight into electricity include, for the most part: i) building- integrated "flat-plate" PV solar panels (rooftops/solar farms), and ii) ground-based continuous flat PV arrays, both depending on direct or normal exposure to solar radiant energy to produce their rated power outputs. Most of these conventional set ^¬ ups pose several common yet serious limitations especially when used in medium- and large-scale applications (i.e., at the hundreds of KWs and MWs power output levels) :

The conventional flat PV solar panels operate at conversion efficiencies ranging from 1 2% to 18% and, therefore, a typical solar utility plant requires a considerable number of panels as well as a large surface area to install them— for example, a 1 000 kW solar power plant would require the area of a football field (i.e., >=1 0000m ² ) and about 4000 of the better performing 240 watts PV) flat panels currently available on the market (i.e. , 16%-18% efficiency The PV solar panels require reliable weather-proofing to protect them from the long-term degradation of the weather and also large supporting metal structures occupying significant areas of land for installing hundreds of flat PV panels needed for the respective solar' power plants.- That adds considerable installation, maintenance & operation costs to the already high costs of the flat PV panels and their related supporting infrastructure;

The effectiveness of the fixed solar panel arrays is seriously limited by receiving solar energy per day is dependent on longitude, latitude, tilt angle, and seasons. While the sun-following solar panels receive maximum exposure to the sun's radiant energy continuously during the entire day and throughout the year. However, a sun- following tracking system represents a significant expense added to a fixed solar panel power system and its operation also requires parasitic power as a portion of its own production of electricity. As a result, the implementation of a tracking system must be carefully weighed against its actual contribution towards the improvement of the energy production capacity factor in the respective solar power plant;

Most of the present ground-based solar power plants are placed in open flat lands in a fixed array arrangement of the PV panels to make optimum use of the solar radiant energy. While this set-up may be practical for direct solar electrical conversion in remote and rural areas, it does not provide for a compatible economical solution to highly populated urban areas where land is at premium and electrical power is always in large demand. Conversely, the use of remote or rural land for the construction of PV solar power plants to service urban areas may increase the overall energy production costs up to 20%, due to added costs and further power losses through extra transmission and distribution installations required to deliver electricity.

Early attempts to reduce the footprint of the PV solar installations were directed at highly compacted solar panel arrangements having multiple closely spaced solar cells mounted to function through direct interaction with incident sunlight. The prior art patents US4,023,368, evidenced the concept of a three-dimensional (3D) solar panel geometry allowing for a 33% assembly foot-print reduction by using side reflectors to direct incident sunlight onto the underside, unexposed solar cells. Further prior art US4,153,475, discloses a more compact power-generating system having a 3D-stacked solar panel arrangement, so that direct sunlight received from the side edges of the solar panels is redirected to the facing surfaces of each of the solar panels.

It is known to the art that the cost of producing electricity with PV cells can be considerably reduced when a large area of sunlight is concentrated upon a small area of a PV cell, which is currently the most expensive component of the system on a per unit area basis. At the same time, photovoltaic materials are more efficient at higher solar intensity levels than that of ordinary sunlight. However, one important drawback associated with current use of concentrated solar energy with PV cells is the heat build-up due to their inherent low efficiencies— i.e., only a portion of the solar energy is converted into useful (electrical) energy, the rest being absorbed as heat throughout the PV cell. It is critical that the PV cells operate within strict temperature limits in order to maintain their performance at maximum efficiency levels— therefore, adequate cooling is essential (see, US7,081 ,584). Concentrating solar radiation devices can use refractive optics (e.g., parabolic mirrors, trough, cone and trapezoidal-shaped mirrors), and/or reflective optics (lens) and/or a combination of different such optical elements in one or multi-stage arrangements, to yield high concentration ratios on the order of 50x or more suns. Precise alignments of the concentrators with the sun through adequate tracking systems can increase the energy generation up to 30%.

Recent innovations in the field of concentrated photovoltaic (CPV) leading to high performance solar concentrators and new generations of high efficiency PV cells have increased the potential to lower costs of the production of electricity. By using cheap, well-designed optical devices that make the high performance solar concentrators capable to intensify the incident solar radiation from the strength of one sun to the order of 50-1 ,000 or more suns, the required active area of expensive semiconductor material in the PV cells is greatly reduced. However, the CPV are faced with the strong challenges of having to maximize their efficiency and lifetime while operating at elevated temperatures and high concentration solar radiation. Some of the early CPV cells, first used in space applications, are described in a number of U.S. patents including US5, 096,505; US5, 21 7,539; US6.091 .020 and US6,252, 1 55.

Intense development efforts towards improving performance of the CPV solar cells for earth-bound applications have made possible the realization of 25%-42% efficiency levels under high sunlight concentrations with PV cells of the 3rd and 4th generation (i.e., CPV cells and, respectively, multi-junction PV cells) . In the 1980s, innovations in Si-based PV cells led to the development of high intensity multi- junction (MJ) PV cells (i.e. , capable of 40 W/cm ² output power density and an efficiency of 20%) described in a series of U.S. patent No. 4,516,31 4.

The biggest challenges of the CPV are the pointing accuracy to the sun and good thermal management in the area of the high efficiency MJ PV cells. The high concentration photovoltaic (HC PV) cells require precise alignment of the optical devices with the sun— a flat PV panel is able to perform at 90% of its maximum power output even with 20 degrees angular error of its tracking system, while an angular error greater than ±2 degrees in a CPV assembly would render the system's power generation essentially down to zero (see, U.S. Pat. No. 6,091 ,020). In addition, flat panels can take advantage of the diffusively reflected sunlight from the environment, which the CPV cannot access— for example, if a flat PV panel receives 1 ,000 W/m ² in total irradiance, a CPV can access only 850 W/m ² , which is direct normal irradiance. Therefore, with the CPV systems, accurate sun tracking is crucial. Thermal management of the CPV systems has all the thermal challenges of the flat PV systems and, in addition, the challenge of having to conduct heat away from a considerably smaller area of the PV cells than that of the conventional flat PV panels. It is beneficial to keep the PV cells from overheating to avoid a decrease in cell's efficiency and to also prevent thermal stresses that cause interconnect-failures. Several cooling methods can be employed to effectively combat heat build-up in a CPV system including passive cooling heat sinks, active heat sinks (e.g. , water cooling) or spectral cooling, depending on the specifics of the system application and the best fit cooling option for the system integration.

CPV systems are generally grouped into three classes depending on the level of solar concentration: 1 . Low-concentration CPV: 2 - 1 0 suns - these are the simplest systems; they can usually use conventional silicon solar cells, and usually do not require active cell cooling. Low concentration stationary non-imaging optics is most suitable for this application.

2. Medium-concentration CPV: 10 - 100 suns - these systems may use either conventional silicon solar cells or high-efficiency l l l-V multi-junction cells and usually require active cell cooling. One-axis tracking linear concentrators are most suitable for this application.

3. High-concentration CPV: 1 00 - 1000 suns - these systems require extremely efficient (>35%) multijunction cells and sophisticated cell thermal management systems. Two-axis tracking point focus or multistage concentrators are required for this application.

SUMMARY OF THE INVENTION

The present invention primarily relates to a systems arrangements and methods for harvesting solar energy using multistage concentrated Photo-Voltaic (PV) generation as well as thermal management. The proposed systematic approach is closed loop, feedback controlled, automated, remote monitored and supervisory controlled, with dawn to dusk and over the complete year sun sensing and tracking system with a provision of peaking the efficiency in terms of concentration collection, generation and power transportation, which can yield an efficient, low cost system applicable for miscellaneous applications and can be scaled efficiently to a desired size as shown in fig 9 (a) and (b).

It is one object of this invention to provide a novel multistage CPV solar power system operated on concentrated sunlight and is being controlled remotely, that would share some of the benefits of the CPV and other solar power systems aforementioned as well as other benefits that will become evident as described below. The system of the illustrative embodiments of the present invention combines highly concentrated solar energy collection, power generation and transmission technologies with a multistage CPV solar power system in a 3D-configuration for compact and modular implementation in the field deployed, portable roof top and building-integrated applications. The multistage concentrated PV solar power system according to aspects of the present invention comprises a multistage solar collection and concentration assembly, a sun sensing and 2π 4 quadrant solar tracking system, an automated thermal management, a sun tracker arrangement and a switch mode power transmission and storage system compatible with the said CPV system. While the system can be easily installed as a stand-alone portable and remotely controlled solar power harvesting system or incorporated in a building structure as a building- integrated power application, other possible applications are not excluded.

As per one of an exemplary embodiment of present invention there is provided a multistage concentrator, which includes three stages i.e. concentration, collection and receiving of solar energy. The primary concentrator collects the sunlight orthogonal to the tracked moving plane in 2pi and 4 quadrant positioning system with feedback control.

As per another embodiment of the present invention there is provided a sun sensor, which is a 3-Dimensional 2π and four quadrant sun position / intensity detection system with improved contrast and MTF (modulation transfer function) system. This sensor system activates the controller to operational / sleep mode based on the intensity and duration of the sunlight. Based on the intensity of sunlight, the system can put the controller in temporary sleep/night operation.

As per another embodiment of the present invention, there is provided sun tracker arrangement. In contrast to the current technology being adopted with positioning of the concentrator by controlling elevation over azimuth plane being adopted in satellite communications, which limits the operational range for dawn to dusk operation and further the twisting of cables and pipes cause an added problem. The current invention uses 2π4 quadrant sun sensing system in tilt-tilt and incremental positioning mode like a dancing doll over the complete operation without any limitation in dawn to dusk operation. This tilt-tilt mode operates in X-X and Y-Y axes alternatively based on feedback from the sun positioning sensor. This tilt-tilt tracker adopts rack and pinion linear motion into a rotatory motion with a dual axis tilting mechanism of X-X over Y-Y and is supported by simply supported dual beam frame structures. As per another embodiment of the present invention, there is a linear to rotatory motion converter of X-X and Y-Y movement of parabolic dish (primary). The said motion converter is based on well-known rack and pinion arrangement.

As per another embodiment of the present invention, there is provided dual beam frame structures for erection of the multistage CPV as disclosed herein.

As per another embodiment of the present invention, there is provided a thermal management system configured for nullifying the damages caused to the solar panel, as the high intensity concentrated light essentially associated with the heat elements. The said thermal management employs a two stage thermal management. The first stage includes positioning of a thermal barrier between the receiver and the secondary collector.

As per another exemplary embodiment, the said thermal barrier is a toughened low iron glass within which a transparent liquid is allowed to pass through under pressure.

As per another embodiment, the said thermal management also includes an arrangement wherein the solar plane, which is exposed to the impinging sunlight after blocking radiation heat, is also being cooled by convection (heat transfer) by a transparent cooling liquid to the sump which is the primary stage of thermal management.

As per another embodiment of the present invention there is provided switched mode solar power transfer and storage. The CPV power transfer in switch mode is new concept for the regulation of solar CPV power, being harnessed to the regulator or inverter. This switching scheme improves the efficiency and minimise heat losses.

Thus the present invention teaches a novel combination and arrangement of parts, either commercially available or specifically designed and described below. It should be understood that changes and variations may be made in the detailed design of the parts, including the solar concentration means, the HC sunlight transmission and light distribution devices and the compact 3D CPV assembly, thermal management, power transmission and storage without departing from the spirit and scope of the invention as claimed.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig 1 illustrates the basic block diagram of multistage CPV in accordance with the present invention;

Fig 2 (a) illustrates a line drawing of the optics of multistage CPV including three stage concentration, collection and reception in accordance with the present invention;

Fig 3 (a) illustrates the basic block diagram of sun position detector in accordance with the present invention;

Fig 3 (b) illustrates a schematic top view of the sun position detector with square base in accordance with the present invention;

Fig 3 (c) illustrates a schematic side plan view of the sun position detector with square base in accordance with the present invention;

Fig 3 (d) illustrates circuit diagrams of the LDR's of sun position detector for sensing the presence and direction of sunlight (Analog and Digital)in accordance with the present invention;

Fig 3(e) illustrates a flowchart of the LDR's of sun position detector for sensing the presence and direction of sunlight in accordance with the present invention ;

Fig 4 illustrates a pictorial representation of a parabolic dish with solar panel mounted on dual axis tilt/tilt tracker in accordance with the present invention ;

Fig 5 illustrates a line drawing for the Sun tracker arrangement in 2π 4 quadrant system configured for tracking sun position in accordance with the present invention;

Fig 6 illustrates the line drawing of the dual beam frame structure configured for robust erection and smooth movement of the multistage CPV in accordance with the present invention;

FIG. 7(a) is a exploded view illustrating the mount structure and coolant flow in a solar photovoltaic panel system according to a general embodiment of the present invention ;

FIG.7(b) is a schematic diagram illustrating a cooling system of solar PV panels from a first view angle according to an exemplary embodiment of the present invention; FIG. 7(c) is a diagram illustrating inline chillier in accordance with the present invention;

Fig 8(a) illustrates the block schematic of switch mode bucket brigade charge storage and transfer scheme in accordance with the present invention;

Fig 8(b) illustrates an input conditioning and current storage section in accordance with the present invention;

Fig 8(c) illustrates an energy transfer and charge storage mode in accordance with the present invention;

Fig 9(a) illustrates a line drawing of the ^: multistage CPV in accordance with the present invention;

Fig 9(b) illustrates a pictorial representation of the multistage CPV in accordance with the present invention;

DETAILED DESCRIPTION

The embodiments of multistage reflective concentrated photo voltaic (CPV) power generation system as shown in fig 1 and 9 respectively and the method thereof such as herein described is selected systems selected for the purpose of illustrating the invention include a primary parabolic sunlight concentrator, a collector and a receiver.

FIG. 1 shows a block schematic diagram of the proposed system with multistage CPV- system for concentrating and transforming solar energy into electrical energy. The proposed system includes a primary parabolic concentrator configured for reflecting all impinging solar insolence to its focal point which is collected and further concentrated by a secondary collector concentrator and thereafter exposed to a receiver solar panel configured for efficient conversion of concentrated solar insolence to equivalent electrical power. The system further includes a sun sensing and sun tracking mechanism configured for sensing and tracking the real time location and intensity of the available sun light. The sun sensing and tracking mechanism as disclosed herein is based on 2π and 4 quadrant topology. The sun position sensor is mounted on disclosed multistage concentrated photo voltaic system for real time sensing and tracking of sun round the clock over the year continuously. The system also includes thermal management solution and switched mode power transfer solution configured for cooling the system and further transferring the generated power for onward transmission and conditioning/or storage.

OPTICS:-

As discussed above, the proposed system includes a primary parabolic concentrator configured for reflecting all impinging solar insolence to its focal point which is collected and further concentrated by a secondary collector concentrator and thereafter exposed to a receiver solar panel configured for efficient conversion of concentrated solar insolence to equivalent electrical power. In an exemplary embodiment, there may be a plurality of collector concentrators wherein the said collector concentrators face each other and their focal axes coincide each other. Further the focal axis of the primary concentrator is also coinciding with the focal axes of the collector concentrators. The plurality of collector concentrators are so arranged so that the solar insolence reflected by the primary concentrator gets reflected and concentrated from first collector and thereafter second collector and so on till it hits the solar panel.

A line schematic diagram showing the multiple reflections through primary concentrator and collector concentrator is shown in Fig 2. During the movement of the Primary Concentrator, the respective / relative movement of the collector concentrator and the receiver is similar and is a constant. The arrangement may further include a sun sensing and sun tracking mechanism configured for sensing and tracking the real time location and intensity of the available sun light as exemplary embodiments. The sun sensing and tracking mechanism as discussed herein is based on 2π and 4 quadrant topology. The sun position sensor is mounted on disclosed multistage concentrated photo voltaic system for real time sensing and tracking of sun round the clock over the year continuously.

The optics for the disclosed multistage CPV comprises of three stage concentration collection and reception as shown in Fig 2. The optics essentially comprises of an octagonal mirrored primary concentrator using array of special mirrors which are explained in the section below to concentrate the sunlight falling on penumbra regions and which is normal to the axis of the parabola at a focal point (F1 ) with a length of (f1 ). A secondary collector mirror which is also an array of mirrors and positioned at the intersection of primary focal point and a secondary focal point f2 with a separation of 2xf2. The collector parabolic dish collects all the reflected light from the primary concentrator and refocus it to a point F2 which is at a distance of 2 ^* f2. The available flatbed solar panel with an area of (A) is positioned at a distance of F2 from the collector parabola in both the axes (xx-yy).

A concentrator is designed to operate under illumination for greater than 40 to 100 suns. The short-circuit current from a solar cell depends linearly on light intensity, such that a device operating under 40 suns would have 40 times the short-circuit current as the same device under one sun operation. However, this effect does not provide an efficiency increase, since the incident power also increases linearly with concentration. Instead, the efficiency benefits arise from the logarithmic dependence of the open-circuit voltage on short circuit. Therefore, under concentration, Voc increases logarithmically with light intensity, as shown in the equation below; where X is the concentration of sunlight.

From the equation above, a doubling of the light intensity (X=2) causes a 18 mV rise in Voc■

As an example the primary concentration levels are achieved by the ratio of f(p)/f(c) which is also the ratio of the linear dimensions of the primary concentrator and collector concentrator wherein f(p) is the focal length of primary and f(c) is the focal length of the collector.

Normal solar PV with 12 to 18% efficiency will generate a power of the order of 120 watts to 180 watts / meter ² of solar cells which are essentially connected either in series or parallel ( Electrically) to obtain the required Voltage and current. The current is linear with insolence, Hence by collecting the sun light over a large area and direct the concentrated light to a Receiver like solar PV module generates at higher current. Thus CPV achieves higher power output from the conventional solar panel.

Normally for 1 MW power generation :-

Conventional PV needs 4000 no of solar PV modules of 250 watt/module (size 1 .6m x 1 meter).

As an example, the proposed CPV with approximately with concentration ratio of 40, only 1 00 No of 250 Watt modules ( size 1 .6m x 1 meter). The area concentration is the product of longitudinal concentration and Lateral concentration C_ longitude x C _ Lateral. But to achieve a concentration ratio of 40 It is proposed to multi stage concentrator with primary Linear concentration of 5 (single axis along 1 .6 m) and a secondary concentrator of 1 along 1 .6 m along 1 m direction of the solar panel and employs conical/parabolic through feed concentration.

For example

In the case of concentrated PV solution with concentration ratio of 40 the power output from the pane! is 6000 watts and thermal radiation on the CPV module is of the order 32000 to 34000 watts. This example exhibits the merit of performance of CPV which generates the power from 240 watts to 1 0000 watts with a receiver area of 1 .6 meter ² . The area of collector area need to be 40 times the size of receiver (Solar PV module) i.em ² .( which will be achieved by area concentration of ( 5 times longitudinal direction and ( 5x 1 .6 times in the lateral direction).

A typical size of CPV is explained below:-

1 st stage concentration 5 x 1 .6= 8 meter in longitudinal direction.

2nd stage concentration of 1 x in longitudinal direction, and 1 .6 x in lateral direction.

Then the overall concentration will be 40 x or higher

The efficiency benefits of concentration may be reduced by increased losses in series resistance as the short-circuit current increases and also by the increased temperature operation of the solar cell. As losses due to short-circuit current depend on the square of the current, power loss due to series resistance increases as the square of the concentration. In another specific embodiment of the invention, the primary concentrator and collector concentrators are assembled in piece wise parabolic and conical reflectors. Pieces of reflector panels are fixed over a parabolic base to form a primary concentrator. These pieces are fixed over the base by using readily available Velcro tapes so that they can be easily attached and replaced. The sides defining the front surface of the reflector panels form the shape of a square. However, it is within the scope of the present invention to have reflector panels with any shape or combination of shapes which facilitate efficient packing within a two-dimensional plane as is well-known in the art. Examples include triangular, rectangular, hexagonal, or octagonal shapes. The reflector panels preferably have a front surface which is optically flat and provides for specular reflection of incident radiation. In one embodiment, each reflector panel comprises male and female connectors formed at each side of the reflector panel at positions along the panel centerlines. The connector type preferably alternates between male and female around the perimeter of each individual reflector panel. The male and female connectors are capable of interlocking via a snap-together feature. A taper is incorporated into the interlock such that when a plurality of reflector panels are arranged into a two-dimensional array, the entire grid of reflector panels can be contoured to the desired bend angle in both horizontal and vertical directions. The bend angle is such that the surface contour formed by the arrayed reflector panels corresponds with surface of a parabola or cone.

In one embodiment the reflector panels are formed from a plastic or composite material which yields a finished product of excellent hardness, rigidity, and durability and which is compatible with the process used to impart reflectivity to the front surface. In yet another embodiment the reflector panels may be formed from a lightweight metal such as aluminum, titanium, or related metal alloys. In an alternative embodiment the reflector panel is formed from a granular plastic material comprising a plastic material and an inorganic additive. The plastic may be selected from polycarbonate, olefin resins, ABS resin, recycled synthetic resin material, and styrol resin.

In yet another embodiment a specularly reflective surface may be imparted to the reflector by the formation of a highly reflective coating. The reflective coating may include a hot-stamped metal foil or reflective glass-free polymer-based film having at least one reflective layer coated thereon. The coating may be of nickel/copper/nickel/chromium multilayer structure.

The multistage concentrator according to aspects of the present invention comprises a multistage solar collection and concentration assembly. As per another aspect of the present invention there is provide a sun sensing and 2π& 4 quadrant solar tracking system which operationalizes the disclosed multistage solar concentrator in real time for continuous uninterrupted power generation.

As per one of an exemplary embodiment the multistage concentrator, includes three stages i.e. concentration, collection of solar energy and further receiving by a solar panel for generation of solar power. The primary concentrator collects the sunlight orthogonal to the tracked moving plane in 2π & 4 quadrant positioning system with feedback control. As per another embodiment of the present invention, there is also provided dual beam frame structures for erection of the multistage concentrator.

SUN POSITION DETECTOR (SUN SENSOR):-

In another exemplary embodiment and as shown in fig 3 there is provided a sun position detector assembly comprising a square base member; a rigid post extending vertically from said base member; a single inner set of square blocks, each of said blocks toeing of successively decreasing size and equal height (thickness with conforming in size and configuration to the outer periphery of the corresponding step portion and having an opening of the same size configured to allow said blocks to be stacked in telescopic pyramidal shaped order on said post to form a rigid central body of stepped formation with the largest block engaging said base member and wherein the height of the blocks are equal to the step width; a plurality of sensors placed on a central middle position along all the four side and over the exposed base area of each square block including a single sensor, centrally disposed over the topmost square block; and wherein the sensors of each side (north/south/east/west, X-Y) are connected in parallel separately for each direction/axes;wherein the step formed walls adjacent to the respective sensors, act as a light blocking member for each connected sensor and thereby provides a differential output based of respective illumination / activation from the exposed sunlight; and whereinthe output of sensors of each side and the output of the centrally disposed sensor are compared and processed for effective calculation of the sun position using a processing system. In an example, the sensor may be high quality LDR's.

The position of the sun is decided by two angles in spherical coordinates; the Altitude angle which is the angle of the sun in the vertical plane in which the sun lies, and the Azimuth angle which represents the angle of the projected position of the sun in the horizontal plane. These two angles will be discussed deeply later in this document. The solar radiations falling on the solar cell array will be maximum when the angle of incidence on the panel is 0° which means that the panel is perpendicular to the sun.

LDR'S:-

LDR's are light dependent devices whose resistance is decreased when light falls on them and that is increased in the dark. When a light dependent resistor is kept in dark, its resistance is very high. This resistance is called as dark resistance. It can be as high as 1 0 ¹² Ω and if the device is allowed to absorb light its resistance will be decreased drastically. If a constant voltage is applied to it and intensity of light is increased the current starts increasing. The LDR's are less sensitive but more stable and long lasting with relatively contant output performance than photo diodes and photo transistor and for that reason are used herein in the form of an array.

SUN POSITION DETECTOR

The sun position detector assembly herein disclosed and shown in Fig 3 (b), (c) comprises of a square base member. From the centre of the square base member, a rigid post is provided extending vertically from said base member. Over the square base member a plurality of single inner set of square blocks, each of said blocks being of successively decreasing size ^' and equal height and thickness with conforming in size and configuration to the outer periphery of the corresponding step portion are placed. These blocks are having an opening of the same size in the centre and configured to allow said blocks to be stacked in telescopic pyramidal shaped order on said post to form a rigid central body of stepped formation with the largest block engaging said base member and wherein the height of the blocks are equal to the step width. A plurality of sensors (LDR's) forming an array are placed on a central middle position along all the four side and over the exposed base area of each square block including a single sensor(LDR), centrally disposed over the topmost square block. The sensors (LDR's) of each side (north/south/east/west, X-Y) are connected in parallel separately for each direction / axes. The step formed walls adjacent to the respective sensors (LDR's), act as a light blocking member for each connected sensor (LDR) and thereby provides a differential output based of respective illumination / activation from the exposed sunlight. The output of sensors (LDR's) of each side (N/S/E/W) and the output of the centrally disposed sensor [LDR (C)] are compared and processed for effective calculation of the sun position using a processing system.

In an embodiment, the 3D sun sensor herein disclosed is a sun position and sun intensity detection device, which comprises of four adjacently positioned LDR area detectors including parallely connected array of LDR's, positioned in each quadrant of the 2π plane with a blocking vertical plane (mask) to eack LDR as discussed above in order to maximise the contrast output during large deviation of sun positions between X_X and Y_Y planes as shown in Fig 3 (a), (b) and (c). The presence or absence of the sun position (analog and digital) can be obtained by comparing with the threshold control loop to put the control system in operation. As the control algorithm is essentially a null seeking system and the variations of intensities between the complementary pairs will be independent of sun intensity variation over the day and over the years. A complete loss of intensity will enable the control loop . to be in sleep mode or operational mode in respect of the presence / absence of sun. The presence of sun will activate the operation when any of the detector is above the threshold level. Below the threshold, the system will enter into sleep mode.

The salient features and the design features of the sun sensor is dependent upon the required concentration of the sun. The equation for the distance and the height of the barrier between the detectors is a function of the concentration ratio which is essentially of:

sin 9 _c = 1 /C _R _L X = distance of x axes LDR from centre

Y = distance of y axes LDR from centre

Z = height of barrier.

The ratio of Z/X=tan θ ₀ Similarly Z/Y=tan θ ₀ where x and y are the position of sensors in X-Y plane and Z is the height of barrier.

Noise immunity has been effectively taken care of with customization of the height of the barrier and further with the use of plane glass fitted LDR, thereby providing a high CMRR.

2Π SUN POSITION DETECTOR AND PROCESSING ALGORITHMS AND SCHEME

The sensors which are proposed to be used are LDRs (Light dependent resistors). To overcome the noise and glitches The LDR are normally positive biased. The SUN position in east-west is detected by acquiring the signal voltages (V_East and V_West). By calculating ratio of (V_East - V_West) / ( V_east + V_West).

The SUN position in north south is detected by acquiring the signal voltages (VJMorth and V_South). By calculating ratio of (V__North - V_South) / ( VJMorth + V_South).

The vectored result of the calculation defines the position of Sun with respect to the tracker and concentrator. The tracking function of the tracker can be controlled by comparing V_East+V_ West with respect to a reference voltage to determine the presence or absence of Sun.

As per the discussed embodiment the four different arrays of parallel connected LDR Sensor's, positioned in four quadrants as shown in Fig 3(a) is used to sense the light and if the sun changes its position then respective LDR Sensor senses the proportionate change in the light falling on them and generate a proportionate representative Voltage signal and the said voltage signal fed to the comparator IC. All voltage signal of the each array of LDR sensors including the output of the centrally disposed LDR are compared by a microprocessor / comparator are fed to the microcontroller as shown in Fig 3(c). The stepwise positioned LDR's present in all the directions are connected in parallel as shown in Fig 3(c). The output of the parallel connected LDR's in each direction is represented as LDR N, LDR S, LDR E, LDR W and the output of the centrally disposed LDR is represented as LDR Ref respectively. The output of the LDR's are FED to a Conditioner and Error amplifier circuit for correction of any presence of noise in the signal strength. The error free signal is fed to a controller (microcontroller) for evaluation. Microcontroller receive the voltage signal from the any i/o pin of the microprocessor/comparator and compares the each LDR array output signal with corresponding each LDR sensor output. The comparison is done with opposite side sets of LDR's like (East - West and North - South) and fed to the servo motor actuators configured for the real time alignment of the solar concentrator assembly in the direction of the sun through a limit switch. When the controller find the Highest voltage level of any LDR sensor, then it gives the instruction to the motor actuator through the motor actuator driver circuit to rotate the solar panel on the single axis in the direction of the LDR sensor which are generating highest voltage output. The activation of the motor actuator is stopped immediately when the difference in the output of the arrays of LDR's is '0' or Nil. By using external two motor actuators and by making connection in parallel we can move the solar concentrator assembly in any direction. As by rotating the solar panel in the direction of the sun we utilize the maximum energy of the sun.

BARRIER HEIGHT AND LOGICS

According to another aspect of the present invention, there is provided four sets of array of LDR's mutually connected in parallel and separate for each direction including (north, south, east and west)comprising four photosensitive areas placed on a surface, each photosensitive area comprising a set of paralely connected LDR's adapted to produce a signal in response to a light beam incident thereon with said signals being useful to calculate a direction of said incident light beam, and comprising an adjacently disposed opaque mask to each exposed LDR for casting a shadow on said LDR, said LDR being characterized in that said opaque mask is arranged in order to mantain a predetermined distance away from said LDR , said opaque mask being shaped and sized so that, in a top view, it occludes a predetermined percentage of each photosensitive area. As it is known by a skilled person and also discussed in the prior art that the output signals of two LDR's / photo sensors (photosensitive areas) arranged on a flat surface can be used to track a light beam incident thereon along one direction; an array of three or more photosensors anyway arranged on a surface can be used, by providing a proper calculation algorithm, to track a light beam incident thereon along two (perpendicular) directions in the plane. Advantageously, in a particularly efficient and cost effective layout for performing tracking of a light source along two directions, the four sets of array of parallely connected LDR's used is a quadrant photo sensor comprising a plurality of photosensitive areas in all four directions arranged in quadrature on a equi-stepped surface, wherein each photosensitive area comprising at least one LDR element adapted to produce a signal in response to a light beam incident thereon with said signals being read in pairs to calculate a X and Y directions of said incident light beam, and said opaque mask extends to each adjacently placed LDR of said quadrant photodetector up to occlude a predetermined same percentage of each photosensitive area.

The particular design of the sun position detector architecture allows a comparably greater accuracy with respect to the prior art in a little angle range but it provides sun direction information in a wide angle range: ± 90 ° on all four directions with respect to the central axis, in order to find the solar position starting from any initial tracker position. This feature is useful in the first tracking system initialization or after an energy blackout. In fact, the above allows a quicker installation process as there is no need of performing an accurate alignment of the sun tracking system during installation.

Following are the exemplary features which are the distinguishing and synergestic effect for establishing inventivess over the discussed prior art:

1 . No discontinuity in the position detectionirrespective of any LDR failure in the array.

2. The position of sun can be grey coded for the range and accuracy.

3. As the sun position detection assembly system is a null seeking tracker discontinuous boundaries poses the hunting problem in the control loop. 4. Since the LDRs are connected in parallel as shown in Fig 3, the output will be maximum in the tracked position ensuring the high signal to noise ratio.

5. As the LDRs are connected in parallel the dynamic range of the sensing the sun position is maximum with high level of contrast. Also ensures seamless analog output.

6. The output of the sun position detector can be used in digital mode with 7 bit accuracy or it can be in analog mode with dynamic range extending many folds .

The sensor availability reliability and continuous mode of sensing the sun position will be greatly extended. The sensor also can be used for detecting sun rise and sun set conditions with appropriate technique. The sun position can be estimated by equation:

Sun position_EW =(V_east-V_west)/(V_east+V_west) . irrespective of sun's intensity.

Sun position_NS=(V_north_V_South)/(V_North+V_South)

Sun's intensity can be estimated by equation (V_east+V_west) and compare with threshold levels

Sun's intensity can be estimated by equation (V_North+V_ South) and compare with threshold levels

Design of the XY positions for the sensor.

The field of view of the sensor if 90° in North, south, east, west directions are divided into 8 grey levels.

i.e. 90/7= 12.5 ° .

The width of the LDRbase (step base width) is a function of cos 12.5"

The height of the LDR barrier wall corresponds to sin 12.5 ⁰ .

The total sum of each block as the sensor is vertically grown reached to 90" and thus satisfying the functional requirement.The features of the LDR sensor is the sensor output which is continuous function. The sun position detector can be used in analog mode or digital mode.The sensor output will be maximum in sun orthogonal position hence improving the signal to noise -ratio and has a large dynamic range and no boundary limitations as posed by the slit sun sensors. According to another aspect of the present invention, there is also disclosed a method for detecting the sun position in real time using three dimensional four quadrant sun position detector configured for aligning the orientation (azimuth and elevation / X and Y) of a solar power generator with the direction of the light coming from the sun, said system comprising a horizontal support member parallel to the horizontal axis of the solar power generator where the disclosed sun position detctor is firmly mounted, a processing unit for processing data from the sun position detector and controlling a drive mechanism comprising a first actuator for horizontal sweeping (azimuth) and a second actuator for vertical sweeping (elevation), the processing unit controlling said first and second actuators according to X and Y position values calculated based upon the outputs of sun position detector, said sun position detector comprising an array of LDR's mutually connected in parallel and separate for each direction including (north, south, east and west)comprising four photosensitive areas placed on a surface, each photosensitive area comprising a set of parallely connected LDR's adapted to produce a signal in response to a light beam incident thereon with said signals being useful to calculate a direction of said incident light beam, and comprising an adjacently disposed opaque mask to each exposed LDR for casting a shadow on said LDR, said LDR being characterized in that said opaque mask is arranged in order to mantain a predetermined distance away from said LDR , said opaque mask being shaped and sized so that, in a top view, it occludes a predetermined percentage of each photosensitive area, said X and Y position values being each calculated by said processing unit according to output values from the array of LDR's of at least two different quadrants with a readout per pair. The reference voltage may be drawn with the full exposed and centrally disposed LDR. Further the said method being further characterized by a condition that when said processing unit is not able to perform the calculation of said X and Y position because of a too great misalignment of said quadrant photodetector relative to the sun, it uses output information from the illuminated LDR's of the exposed photosensitive areas with respect to the centrally disposed LDR for initiating the action of determining which is the direction where said first and/or second actuators have to be operated in order to realign said sun position detector, and it consequently operates said first and/or second actuators until it is able again to perform the calculation of said X and Y positions. Basically the algorithm as shown in Fig 6 is based on the difference calculation, but each time the tracker alignment is out of the acceptable tolerance, the four quadrant sun position detector gives the right signal in order to correct the future trajectory.

Once the LDR's symmetry axis has been aligned to the sun, the power produced by an associated solar power generator is monitored by operating said first and second actuators, in order to find the Xpmax and Ypmax values which maximize the energy produced by said solar power generator.

Control Algorithms and logics as shown in Fig 3(e)

a) Power ON self - test of the tracker logic;

b) Wind speed check to be below specified limits;

c) The tracker position to be within limits;

d) Sun intensity above limits;

e) First NorthJSouth movement is performed till the peak position reached. f) After the North_South movement is stopped, East _West direction movement is accomplished;

g) Step e and f will be repeated till the position error reaches below the threshold is detected.

The 2π sun Sensor and sensor electronics SUN position sensing and processing algorithms and scheme:-

• The sensor which are proposed to be used are LDRs (Light dependent resistors)

• The construction sensor should block sun light illuminating the LDR_East should not illuminate the LDR_West. Until Sun illumination is equal on both LDRs.

• The same logic holds good for North_South LDRs.

• To overcome The noise and glitches The LDR are normally positive biased.

• The SUN position is detected by acquiring the signal voltages (V__East and \M/Vest). By calculating ratio of (V_East - V_west) / ( V_east + V_West).

• The vectored result of the calculation defines the position Sun with respect to the tracker and concentrator

• V_east+V_West will show the Sun's Illumination conditions. • The tracking function of the tracker can be controlled by comparing V_East+V_West with respect to a reference voltage to determine the Presence or Absence of Sun.

• In the case of CPV, keeping the voltage same as in conventional PV ( by maintaining the solar PV temperature) the current levels shoot up as much as the concentration ratio.

• The primary concentrator collects the sunlight orthogonal to a tracked moving plane in 2π 4 quadrant positioning system with feedback control.

SUN TRACKER :-

As per another embodiment of the present invention, there is provided sun tracker arrangement as shown in Fig 4 and 9(a). In contrast to the current technology being adopted with positioning of the concentrator by controlling elevation over azimuth plane being adopted in satellite communications, which limits the operational range for dawn to dusk operation and further the twisting of cables and pipes cause an added problem . The current invention uses 2π 4 quadrant sun sensing system in tilt- tilt and incremental positioning mode like a dancing doll over the complete operation without any limitation in dawn to dusk operation. This tilt-tilt mode operates in X-X and Y-Y axes alternatively based on feedback from the sun positioning sensor. This tilt-tilt tracker adopts rack and pinion linear motion into a rotatory motion with a dual axis tilting mechanism of X-X over Y-Y and is supported by simply supported dual beam frame structures.

In another embodiment the sun position tracker is configured for supporting concentrated photo voltaic (CPV) power generation system, said sun position tracker further configured for moving said CPV for tracking the path of the sun, said solar tracker comprising: a CPV power generation system supported on the open cage like structure disposed on gimbal (V frame) with a base configured for rotatably supporting the gimbal at a given orientation from the ground, the ground support and two V shaped frames are located on separate platforms and are further supported over four pillar structure which are grouted to the earth thereby providing three dimensional stability including means for raising, lowering and changing orientation of the gimbal; wherein the said platforms support the V shaped frames are driven by linear rack and pinion arrangement and the said platforms are hinged to the respective base structure with bearings providing dual axis and vertical tilt with five degrees of freedom.

The embodiments of tilt-tilt dual axis sun position tracker for concentrated photo voltaic power generation system employing longitudinal tilt (N_S) and Lateral tilt (E_W), incrementally is shown in Fig 5 and 9(a). The proposed system employs 4 quadrant sun sensors ( LDRs / PV cells) with proper geometry of the sensor blocks supports 2 π tracking over the day and year in closed loop and controlled by limit switches. The purpose of a solar tracker as herein disclosed is to accurately track the position of the sun. This enables solar panels interfaced to the tracker to obtain the maximum solar radiation. With this particular solar tracker a closed-loop system was made consisting of an electrical system and a mechanical system. The sun position tracker comprises of two V shaped frames which are located on to a simply supported four pillar structure which are grouted to the earth with proper foundation.

As discussed, the primary issue for maximum harvest, which is to be taken into account in CPV is that angle of illumination or insolence is necessarily normal/ orthogonal to solar PV panel. The angle of insolence is very critical with higher concentration ratios. This calls for an accurate sun tracking systems on which the concentrator optics and solar PV receivers are mounted.

Conventional sun dual axis tracking systems incorporate methodology of Tilt - tilt rotation for elevation tracking and rotation for azimuth tracking similar to satellite tracking solution of communication system.

These systems use the sun position based on the ephemeris of the sun and earth positions as calculated from astronomy. Then technology suits well for geostationary satellites and rotating earth. The rotation of tracker in azimuth complicates the cabling and piping designs or tracker automation systems by sensing the limit switches ensuring the no jumbling of pipes and cables. This being an open loop control system the tracking accuracy depends on the information of longitude and latitude of the installation and time of the day. In contrast, the disclosed sun tracking system is a longitudinal tilt (N_S) and Lateral tilt (E_W), incrementally. Hence high speed tracking on longitudinal/lateral directions are avoided. The proposed system employs 4 quadrant sun sensors (LDRs / PV cells) with proper geometry of the sensor blocks supports 2 ττ tracking over the day and year in closed loop which is known to a person skilled in the art and is further controlled by limit switches. This tracker allows the independence from installation requirement of aligning the axes in North_South direction over year and East_West Direction over the day.

There is no necessity of feeding sun position or location data for tracker controlling purpose. (Accurate longitude and latitude data during initial set up of the tracker.) The position of the tracker is processed to be independent of sun light intensity. By setting threshold for intensity, the start and stop function of the sun tracker can be controlled. The movement of tracker could be very slow over the day and over the year. Incremental movement of tracking is being implemented.

The tracker functions dual axis tilt-tilt mode of traverse. Also the tracker movement is essentially an incremental rotational movement. The platform and dish will be a driven by linear rack and pinion connected to platforms and the platforms are hinged to the respective base structure with bearings. The dish is mounted on a 5 dof (5 degrees of freedom) gimbals (V frames).

Mechanical design of tracker and dynamic envelope estimation

The Tracking principle of dual axis tilt platform mounted on 4 pillar structure with 4 degrees of freedom. (North, South, East and West and vertical tilt forming 5 degrees of freedom). The design of structure takes in to account of self-loading and wind load as per international standards of self-load in worst case condition and wind loads. In an example : the tracker is configured to stop tracking for wind loads > 70 km/ hr. The design also includes a closed loop automation algorithms and control logics which include motor control and interlock logics.

The design of the sun tracker as shown in Fig 6 includes the different safety interlocks available and is taken into account. The extreme limits, wind loads and intensity of illumination for safe operation of the tracker. The pulse currents form the tracker and checked for proper functioning of the rack and pinion movement and rotation of the platform in both axes. The sun tracking system employs a PLC based control application which tracks the sun in 2π 4 quadrant motion (dual axis), with incremental motion on each direction, by the use of linear to rotary motion converter. The sensor used for tracking the sun position is 4 quadrants LDR based sun sensors. The additional feature is PLC based self-cleaning facility.

Control Algorithms and logics

a) Power ON self - test of the tracker logic;

b) Wind speed check to be below specified limits;

c) The tracker position to be within limits;

d) Sun intensity above/below limits;

e) First X-X movement is performed over the specified duration; ^'

f) After the X-X movement is stopped, Y-Ydirection movement is accomplished; g) Step e and f will be repeated till the position error reaches to zero and below the threshold being detected.

The 2π sun Sensor and sensor electronics SUN position sensing and processing algorithms and scheme:-

• The sensor which are proposed to be used are LDRs (Light dependent resistors)

• The construction sensor should block sun light illuminating the LDRJEast should not illuminate the LDR_West. Until Sun illumination is equal on both LDRs.

• The same logic holds good for North_South LDRs.

• To overcome the noise and glitches The LDR are normally positive biased.

• The SUN position is detected by acquiring the signal voltages (V_East and V_West). By calculating ratio of (V_East - Vwest) / ( V_east + V_West).

• The vectored result of the calculation defines the position Sun with respect to the tracker and concentrator

• V_east+V_West will show the Sun's Illumination conditions.

• The tracking function of the tracker can be controlled by comparing V_East+V_West with respect to a reference voltage to determine the Presence or Absence of Sun. • In the case of CPV, keeping the voltage same as in conventional PV (by maintaining the solar PV temperature) the current levels shoot up as much as the concentration ratio.

• The primary concentrator concentrates the sunlight orthogonal to a tracked moving plane in 2π 4 quadrant positioning system with feedback control.

LINEAR TO ROTATORY MOTION CONVERTER:

The sun tracker as disclosed herein is configured for X-X and Y-Y movement of parabolic dish (primary). The tracker functions dual axis tilt-tilt mode of traverse. Also the tracker movement is essentially an incremental rotational movement. The platform and dish will be a driven by linear rack and pinion connected to platforms and the platforms are hinged to the respective base structure with bearings as shown if Fig 6.

DUAL BEAM FRAME STRUCTURES:-

The currently used as prior art pole structure with a rotating pillar for azimuth rotation with tilt of dish accomplished by bearing structure. The limitation of positioning is limited to the tilt of the concentrator in elevation position and also limited by the rotation envelope of the azimuth however the existing systems do associate yrerotary motion of the cables and pipes twist / untwist leading to thermo-mechanical fatigue / failures.

The present invention discloses the use of four pole structure as shown in Fig 5, wherein each poles is grouted at four corners of a square / rectangle and a centre pole at diagonally middle portion for central and peripheral support of the multistage CPV. During the erection, the extreme limits, wind loads and intensity of illumination for safe operation of the tracker. During assembly, the pulse currents form the tracker and checked for proper functioning of the rack and pinion movement and rotation of the platform in both axes.

Dual axis feedback sun position sensor

The 3D sun sensor is a sun position and sun intensity detection device, which comprises of four LDR area detectors positioned in each quadrant of the 2π plane with a blocking vertical plane to maximise the contrast during large deviation of sun positions between X_X and Y_Y planes. The presence or absence of the sun position (digital) can be obtained by comparing with the threshold control loop to put the control system in operation. As the control algorithm is essentially a null seeking system and the variations of intensities between the complementary pairs will be independent of sun intensity variation over the day and over the years. A complete loss of intensity will enable the control loop to be in sleep mode or operational mode in respect of the presence / absence of sun. The presence of sun will activate the operation when any of the detector is above the threshold level. Below the threshold, the system will enter into sleep mode.

The salient features and the design features of the sun sensor is dependent upon the required concentration of the sun. The equation for the distance and the height of the barrier between the detectors is a function of the concentration ratio which is essentially of:

sin 9 _c = 1 /CF L

X = distance of x axes LDR from centre

X = distance of y axes LDR from centre

Z - height of barrier.

The ratio of Z/X=tan θ|_ _χχ Similarly Z/Y=tan e _c _>, _y where x and y are the position of sensors in X-Y plane and Z is the height of barrier.

The output of the comparing circuit of the sun sensor powers a driver circuit, which in turn powers a motor and changes direction according to which sensor receives a higher amount of illumination. This orients the solar panel to be perpendicular to the sun. The sensor outputs are conditioned, digitized and computed for position sensing accuracy. However the proposed computation ensures the positional accuracy as position information is relative measure of the sun's intensity.

= V-o-Y_s/ V_u+V_s

Where V-n corresponds to voltage developed across North sensor, V_s corresponds to voltage developed across south sensor. V_n-V_s gives the sun position information, V_n+V_s gives the sun's intensity. The ratio of position error and intensity variation is independent of intensity. Similarly east and west sun's position error is computed. The error signals are verified and serve as input to the control generation logic. The other information as dark condition, limit detection, hysteresis of error are all taken into account during the processing and computation.

The error signals of North _South and East_West are scanned at regular intervals and the motors of north/south/east and west are triggered alternately at predefined time intervals ensuring the correction of error is fast enough to position the solar panel orthogonal to the sun illumination or insolence. The positioning of the V frames/ dish with solar panel will be effected by two linear actuators ( rack and pinion actuators).

The sun position/ dish position will be resolved into cosine functions as

COS Θ in north south direction

And

COS φ in east west direction.

Hence the position of concentrator will be orthogonal to sun position over the day and over the year.

The salient features of the invention are:-

The structure of the tracker is simply supported by 4 pillars grouted to the ground, easy to design and implement the structure for high wind loads and maintain the centre of gravity with in the support base.

The two V frames constitute the Dual axis Gimbal structure also supported by bearings on to the main foundation structure, preventing from toppling during tracking and under high wind loads.

Alternate scanning and error correction of the tracker in North/South and East/West directions at sufficiently high speeds will ensure smooth seamless tracking.

The scanning mode also provides the advantage of high torque generated during start leading to minimising the power from the motors.

The main feature of the TILT/TILT mode scan tracking solution is the cabling and piping associated with rotational tracking system coiling of the cables and pipes are avoided. Hence no slip ring requirement or stress and stretching of pipes and coils are overcome

The waviness during the motion can be controlled by suitably selecting the scan frequency and motor speed.

The TILT/TILT scanned dual axis sun tracker ensures longer duration of tracking ( theoretically from dawn to dusk), also independent of positional accuracy during installation and commissioning( other trackers . need to be positioned to north/south direction) The tilt angle in North_South/East_West direction is limited .

THERMAL MANAGEMENT

The sun intensity on earth is 1000w/m ² . Assuming a parabolic dish of 10m diameter 75 m ² approx is the area. The flux concentrated is approximately = 1000x75watts. This much sun radiation is beamed on a collector area of 1 .6x1 m ² therefore the flux density is approximately 41000w/m ² . The temperature thus raises from 40-50deg on the earth to 300 - 500°C at the collector. To keep the solar panel in safe operating temperature range it needs to be kept below 40 -50° C. Thus imperative that we need to extract the heat component from the impinging sunlight onto the solar panel.

Step 1 : Since the collector area is divided into equal segments to ensure the flux density over the segmented area is minimized. Also we should take into account, the attenuation of the light intensity should be kept minimum when it reaches the solar PV. A trade-off of maximum heat extraction with minimum attenuation of the light intensity needs to be achieved. This call for the segmented structure to be skirted with good thermal conductive material like iron copper or aluminium and these conductive materials are connected in both length and breadth of the barrier design. There connected a separate heat absorbed coolant pipe and cooled coolant pipe configured for deliver and suck coolants and thereby maintaining the temperature on the surfaces of the solar PV's between 30 - 40 degree Centigrade and thus creating a segments of isothermal boundaries of each of the segmented barrier blocks. From the above example it is found the heat flux density of 41000 watts reduces to 41000/160=256 watts. This 256 watts of heat is extracted by the flowing liquid thus maintaining the temperature at close to ambient approx 30-40 ⁰ C. Step 2- Also due to high concentrated light the electric power generated will be multiplied by the concentration level for example 240 watts panel with concentration of 1 00 will generate 24KW of electric power the solar PV's also radiate large quantum of heat energy. With the panel voltage be at 30/60V the current generated will be approximately 800/400 A respectively, with the high current being generated the electrodes of the solar panel will offer higher resistance at higher temperature. Hence it is imperative to keep the temperature at ambient or below ambient. This is being achieved by passing the cooled fluid over the back of the solar panel either directly or with a thermal ladder with high thermal conductivity like aluminium or copper. Also to keep the operating temperature near to the ambient value the solar panel output is switched at high frequency to improve the power transfer efficiency minimizing the thermal losses and also maintaining low temperature gradient between solar cell and output.

The concentrated sun light does also include Heat component, the efficiency of conversion being approx 1 0 to 15%, the rest of the energy is heat component. The operating temperature of solar panel is max 70 °C, it is imperative to maintain panel temp is to be maintained below 70 °C.

Therefore, in order to alleviate and solve the heat dissipation problem , a metai-based heat sink in the form of a base plate e.g. containing heat dissipation fins and a heat dissipation base plate is placed below the solar cells to enhance its heat dissipation efficiency. The base has at least one primary surface to collect heat. Each fin has one or multiple heat-dissipating surfaces. With a relatively low thermal conductivity, a heat sink must have a large number of preferably hexagonal thin fins to have sufficient amounts of heat-dissipating surfaces. However, such a design increases the complexity of manufacturing processes and the production cost. It is clear that the functions and performances of prior art solar cells are not satisfactory. In real practice, Cu and Al heat sinks are formed with fins or other structures to increase the surface area of the heat sink, with air / coolant being forced across or through the fins to facilitate heat dissipation of heat to the air. In addition, the use of copper or aluminum heat sinks can increase the chances of structural stabilityfrom environmental disturbances. The said metals do exhibit a high surface thermal emissivity and thus effectively dissipate heat through the radiation mechanism. The thermal management solution as described herein is essentially blocking the radiation and extraction of heat for converting phase either from Liquid to gas or from solid to liquid at constant temperature as shown in Fig 7(a) which shows a diagram for thermal management of the multistage CPV. The system is kept at a constant temperature and the heat is absorbed by the continuous coolant flow. This is achieved by passing coolant liquid through the bottom portion of the solar PV panel. The effect of temperature raise essentially lowers the PV voltage exponentially. It is most important to maintain the module temperature at ambient or low temperatures. The major problem of temperature raise is that the semiconductor fuses or breakdown occurs when the temperature exceeds the allowable limit of junction temperature (for silicon it is approximately (max1 75 °C).

The first level of thermal management employed includes and active transparent thermal barrier designed with toughened low iron glass and convective flow of cooling liquid.

Cooling: 1 :The invention employs two stage thermal management as under:

Stage_1 : Active cooling has been employed with blocking the radiation heat by toughened glass barrier as shown in Fig 1 and circulating cooling liquid in the barrier. The high intensity concentrated light essentially associated with the heat elements. Between the receiver and the secondary collector a thermal barrier (toughened glass with transparent liquid under pressure is allowed to pass through. The solar panel is exposed to the impinging sunlight after blocking radiation heat and also being convected by the transparent cooling liquid to the sump which is the primary stage of thermal management.

Stage_2: Active fin structure based circulation of coolant liquid is employed.

FIG. 7(a) is a schematic diagram (exploded view) illustrating the coolant flow in a solar photovoltaic panel system according to a general embodiment of the present invention. The, coolant flows in a closed: loop system from a sump / tank source through a coolant supply system to a solar photovoltaic panel. From the solar photovoltaic panel, the coolant flows back to the sump / tank source.

FIG. 7(b) is a diagram illustrating a cooling system of solar PV panels from a first view angle according to an exemplary embodiment of the present invention. The cooling system of solar PV panels includes a panel mounting structure, a first solar PV panel, a inlet outlet arrangement of the mounting structure housing, a sensor and piping arrangement and a coolant second solar PV panel and a coolant supply system.

The panel mounting structure housing, as shown in FIG. 7(b) , contains an inflow section and ah outflow section in the upper chamber and similarly an inflow section and an outflow section in the lower chamber. The panel mounting structure further includes a top plate made of glass and a bottom plate made of glass / metal which may be provided at a same elevation as the outflow section, as shown in FIG . 7(b). The mounting structure is different from the known structures in prior art for the reason that during operation the inclination of the said structure changes with respect to time and position of the sun. In one exemplary embodiment, the inflow sections and the outflow sections during operation may have a same elevation. In another exemplary embodiment, the inflow sections may have an elevation that is higher than the elevation of the outflow sections.

The mounting structure housing is a box like structure comprising two chambers (top and bottom) separated by the installed solar panel at the centre of the housing as shown in figures forming / diving the compartment into two chambers. The width of the top and bottom chambers may be same or can vary as per the requirements. The top chamber and the bottom chambers have separate inlets and outlets. Inside the housing, there is made an arrangement of flow of coolant from top chamber to bottom chambers by making holes on the mounting plate (base plate) of the solar panel. In an exemplary embodiment the solar panel is mounted on a base plate comprising fin like hexagonal structures on its top configured for providing laminar flow of the coolants over its surface and effectively touching the bottom portion of the solar PV panel and the base plate. The idea of the fin structure is basically to increase the active surface area thereby activate efficient cooing. The top enclosure of the mount structure is made up of toughened glass configured for maximum exposure of light energy to the surface of the solar panel. The bottom of the mounting structure is made of glass / metal plate. The side panels of the box like structure are made up of MS plate for exclusively for the holding purposes and forming a robust structure wich ban withstand the weather hazards. The inlets and the outlets of the said two chambers are provided with multiple sensors (pressure and temperature) and solenoid valves for remotely controlling the low of the coolant with respect to the feedback obtained through the plurality of sensors. In an exemplary embodiment, the inlets of the said two chambers are combined and outlets of the said two chambers are combined for operations like a pumping and suction of the coolants simultaneously. In another embodiment, the chambers are further subdivided to satisfy the criteria of laminar flow of coolant inside the chambers. Therefore the base plate may include multiple base plates. The inflow section includes an inflow channel structure and the outflow section includes a panel mounting structure. Coolant is supplied from the sump, provided by a coolant supply system to the inflow section, flows on the surface and back of the said solar PV panel and is directly returned to the a high performance radiator / thermal sink via the outflow section. The coolant of the sump is filtered for any foreign substance and thereafter passed through an inline chiller for the purpose of instant cooling and is pumped into , the inlet sections. No further pipes or other structural elements are required to return the coolant to the thermal sink. A person skilled in the art will be able to understand the very basic purposes of the thermal sink and inline chiller.

A system, which provides coolant from a sump, returns the coolant to the same sump, and "reuse" or provide the same coolant again to the system , is called an closed loop thermal exchange system. The inflow sections may be connected to the vertical structure and the outflow sections may be connected to another vertical structures which may contain another base plate for holding and stability. The other base plate may include multiple base plates, which may also be installed without the other vertical structure for smooth flow and to withstand weather hazards.

The said solar PV panel is mounted between the two said top and bottom chambers with separate inlet and outlet of top and bottom chambers over a base plate having hexagonal or the like fin structure filled with continuous laminar flow of coolant supply configured for maintaining desired temperature at the bottom of the solar PV panel. The laminar flow is extremely important as the maximum transfer of heat takes place under such conditions and turbulent flow can cause disruptions unwanted pressure and of course air bubbles that may reflect incoming light and reduce efficiency of the solar PV panel.

The inlet / outlet flow sections of the panel mounting structure contains an inflow /outflow coolant channel structure for pumping coolant into the top and bottom chambers further comprises of pressure sensors and solenoid valves at inlet / outlet points of both the chambers. The coolant supply system provides coolant to panel mounting structure via a pipe, which may be connected to an internal pipe installed in the vertical structure of the panel mounting structure. In a further exemplary embodiment, the pipe may include a plurality of pipes and may be connected to a system of a plurality of internal or external pipes installed in or on the panel mounting structure. The internal pipes may be connected to the coolant inlet / outlet which is connected to the inflow / outflow coolant channel structure.

A coolant flow control structure is provided with the input feedback of the plurality of pressure sensors and solenoid valves, which controls a flow of coolant on a top and bottom surface of the solar PV panel. The coolant flow control structure provides a laminar coolant flow pattern which may be a continuous and steady coolant layer having an adjustable thickness. Other coolant flow patterns may be generated by the coolant flow control structure such as a discontinuous coolant flow pattern. However, any other structure that allows providing a controlled and adjustable flow of coolant on the top and bottom surface of the solar PV panel, may also be used.

In another exemplary embodiment, an electric step motor for pumping and suction operations may control the operation of the coolant flow control structure simultaneously (not shown) or by another control device, which may be controlled by a computer or control processor (not shown). For example, the electric step motor may control the movement of the solenoid valve or any other controllable valve (not shown) , which may adjust the amount of coolant, pumped inside and / or sucked outside sprayed by the pipes. An overflow outlet may be provided to the inflow channel structure to regulate the coolant level in the inflow channel structure if the amount of coolant provided by the inlet is higher than the amount of coolant flowing through the outlet as the said arrange is subject to a housing whose inclination is continuously changing with respect to position of sun and time.

FIG. 7(c) is a diagram illustrating a inline chiller which is formed with a multiple tubular structure. A refrigerant fluid in ^' passed over a section of inlet piping arrangement with the help of compressor arrangement continuously to instantly cool the coolant liquid passing through the assembly in real time. The inline chiller is configured to instantly cool the coolant to 5-1 0 degree Celsius before pumping it into the housing structure.

The coolant flowing through the inlet and outlet may create a continuous and steady coolant layer on top and bottom of the surface of the solar PV panel. This continuous and steady flowing coolant layer cools the solar PV panel and constantly removes dust and other foreign particles such as debris from the top surface of the solar PV panel. In addition, the flowing coolant layer collects additional solar irradiation due to light refraction. The debris and dust removal and the additional solar irradiation due to light refraction reduce the overall cost and complexity of the system design.

The additional solar irradiation due to light refraction created by various coolant flow patterns increases the energy harvest of the solar PV panel. In particular, the various said flow patterns may have different antireflection properties. The WATER flow control structure is configured to generate or create the various WATER flow patterns.

Depending on the temperature of the solar PV panel, on the amount of dust or foreign particles to be removed, on the angle through which the sunlight arrives at the solar PV panel, or on any other factors, the coolant flow pattern may be changed using the said flow control structure. If the temperature of the solar PV panel is too high, the amount of coolant per time unit provided on the top and bottom surface of the solar PV panel may be increased. Depending, on the angle through which the sunlight arrives at the solar PV panel, the shape of the coolant layer surface may be changed from a continuous and steady laminar surface to a rough or discontinuous coolant layer surface. This provides great flexibility in the flow patterns.

In an exemplary embodiment, preferably, each the internal surface of the mount structure and fin comprises a surface coated with a high-emissivity material having an high emissivity material may be selected from aluminum oxide, zinc oxide, aluminum nitride, titanium oxide, boron nitride, silicon carbide, silicon nitride, gallium nitride, or a combination thereof. The high-emissivity material may be in the form of metal or ceramic nano particles.

POWER COLLECTION AND TRANSPORTATION:

In another embodiment, the power collection and power transfer mechanism provides increased power harvesting and high energy yield minimizing the losses. In accordance with the disclosed subject matter, power harvesting systems are provided which substantially eliminates or reduces disadvantages associated with previously adopted solar cell and module power harvesting systems.

Accordingly, in an embodiment, there is disclosed systems arrangements and methods for harvesting solar energy using multistage concentrated Photo- Voltaic (PV) generation. The proposed systematic approach is configured for a closed loop, feedback controlled, automated, remote monitored and supervisory controlled, with dawn to dusk and over the complete year sun sensing and tracking system with a provision of peaking the efficiency in terms of concentration collection, generation and power transportation, which can yield an efficient, low cost system applicable for miscellaneous applications and can be scaled efficiently to a desired size. The power collection and transportation includes switch mode power transfer of CPV power, which is a new concept of regulation of solar CPV power being harnessed to the regulator or inverter. This switching scheme improves the efficiency and minimise heat losses.

In another embodiment, the present status of power transfer allows continuous current flow from solar power source and loss during the transfer from source to load. In another embodiment, there is provided a circuitry for power conditioning at the panel level: The power is transported and conditioned with switching the panel generated power and transporting to super capacitor bank. The output of the bank is connected to a bank of switched capacitor bank for charging parallel and discharging serially. The DC output of the unit is connected in series or parallel paths to serve as input to grid connected inverter and control panel from which the metered power is fed to the Grid.

As per an exemplary embodiment, the energy is stored in super capacitors are placed close to solar panel thus minimising the high current flow in cables and switched at the panel itself. These super capacitors are cascaded to generate required voltage and power. Also this feature allows an uninterrupted power to load irrespective of shadows created by clouds during day dependent on sizing of the capacitor. The inherent feature of reduction in current flow depending on the charge in capacitor allows switch mode of power collection and transportation.

Thus the present invention teaches a novel combination and arrangement of parts, either commercially available or specifically designed and described below. It should be understood that changes and variations may be made in the detailed design of the parts of power transmission and storage without departing from the spirit and scope of the invention as claimed.

Embodiments described herein provide for an power collection and conversion system for efficiently converting energy and maximizing power output As described herein, the energy collection and conversion system can efficiently convert direct current (DC) energy into alternating current (AC) energy by reducing the number conversions that take place within the system. In addition, while embodiments described herein refer to PV panels as energy source input(s), the concept can be extended, by those of ordinary skill in the art, to other kinds of energy collection/generation or energy storage systems.

POWER COLLECTION AND TRANSPORTATION:

Switch mode power transfer of CPV power: It is a new concept of collection, transportation conditioning of solar CPV power being harnessed to the regulator or inverter. This switching scheme improves the efficiency and minimise heat losses. In the prior art, the power transfer is allowing continuous current flow from solar power source and loss during the transfer from source to load. It may be acceptable limits in the case of conventional PV systems as the current generated is well within the limits of the cable and length between the source and load.

Also continuous high current in the cable leads to higher voltage drop between the source and load (in this case may charger / inverter/multi source combiner circuits) . This phenomenon leads to heavy loss of power and heating up of the cables during the transfer.

As per an exemplary embodiment, the energy is stored in super capacitors close to solar panel thus minimising the high current flow in cables and switched at the panel itself. These super capacitors are cascaded to generate required voltage and power. Also this feature allows an uninterrupted power to load irrespective of shadows created by clouds during day dependent on sizing of the capacitor.

The inherent feature of reduction in current flow depending on the charge in. capacitor allows switch mode of power collection and transportation.

Switch mode Bucket brigade: The switch mode PV generation comprises of array of super capacitors/ batteries charged parallel to achieve the required voltage and charge levels. The discharge of the super capacitors / batteries in series mode achieves the required voltage and charge levels. The switch mode PV generation comprises of array of super capacitors/ batteries charged parallel to achieve the required energy and charge levels. The discharge of the batteries in series mode to achieve required voltage and charge levels.

The bucket brigade switch mode power conditioner comprises of output capacitor C ₂ is charged by the solar panel. The output capacitor is a battery or a super capacitor (C tor C ₂ ). The output of the capacitor in tandem with the solar power charge capacitor Ci , C ₃ , C ₄ C _n in parallel mode for time duration of delta t storing the energy of

e=1 /2C _c ^* V ² wherein V is a function of current density and charge duration.

V=1 /CTA t

The parallel charging of the capacitor / batteries for a period of At determines the power deliver.

During discharge / delivery mode, the capacitors Ci , C3, ...C _n will be connected in series thus resulting in the boosted voltage of n*V typically 600 V for commercially available grid type inverters. Assuming the panel Of 20 capacitors of 30V and each capacitor storing adequate energy for 30 volts during the period of Δ t will discharge the energy stored with adequate input voltage for grid tie inverter. The boosted voltage is transferred to the link capacitor CL which serves as the input for the inverter. Any depletion of charge during discharge mode or transfer mode will result in reduction in voltage and being topped up the solar current C ₂ capacitor storage. This is an analogy with a buckets kept in series being discharged one after another from the output is being replenished by the presiding charged wells (CAPACITORS) . During charge mode i.e. in parallel mode of operation of charging M1 , M2, M5 and M6 will be conducting. During discharge / delivery mode the switches M3, M4, M7 and M8 will be conducting and delivering the output to inverter with link capacitor CL. The system being in switch mode during both charging and discharging operations in high frequency > 20KHz and will drastically reduce the footprint and thermal issues with a benefit of higher operational efficiency.

The solar panels being manufactured are essentially a DC current source with a figure of merit as l_sc ( short circuit current) and V_oc ( open circuit voltage ), which are far less than the voltage and current needed for driving the Grid tie inverter. Current practice is to cascade the solar panels in series and parallel combination to generate required input voltage and current ( in other words power) . With the development of concentrated photo voltaic solutions, the panel voltage remains as in standard PV, however the short circuit current shoots to high values depending on the level of concentration. Thus enabling the designer to generate more power with less real estate requirement. This topology of concentrated photo voltaic scheme demands an innovative interface of boosting the voltage to interface with grid tie inverters and also store and forward the energy to inverter as and when demanded by the inverter. All inverters are essentially switch mode inverters. Fig 8(a) illustrates the schematic of switch mode bucket brigade charge storage and transfer scheme.

BUCKET BRIGADE CHARGE STORAGE AND TRANSFER SCHEME

The proposed scheme consists of

1 . Solar panel

2. Input conditioning and current storage section

3. Voltage_boost and charge storage section.

4. Grid tie interface section.

As explained earlier, the scheme is more suited to concentrated photo voltaic power generation scheme. However the scheme can also be implemented for other applications.

In an exemplary example, the theory of switch mode storage and transfer scheme is illustrated below:

Assuming the power source P in switched at a frequency f_sw

Energy (in joules /Hz)= P(in watts)/f_sw :

Assuming a power of 20KW is to be stored switched and transferred at a frequency of 20 KHz at a voltage of 30V

Energy/cycle= 20000/20000 = 1 joule/cycle

Hence l_sw= power/voltage

i.e I = 20000/30 =666 amps

Inductance L is given by the equation

Energy_L = L*l ²

li.e L=1 /(666 ² )=2.25uH

Energy _L = Energy_C=1 joule

Energy equation stored in capacitor C is given by

Energy_C=0.5 ^* C ^* V ² joules/cycle

C= 5000uF/cycle storage from 1 00% to 10% depth of discharge, hence to minimise the ripple and ensure good load regulation with 3% the value of capacitance needed is 150,000 uF

Voltage V_C is given by equation V_C=( l_sw ^* (1 -D)*AT)/C volts

Where is the duty factor of the switching clock with frequency f_sw By using a super capacitor :

The energy stored can be improved to ensure uninterrupted energy flow to following sections

Boost, charge storage and transfer section:

Voltage boost can be achieved by switching the inductor to short circuit max current flows and inductance stores the energy as explained in the previous section:

V_L= L ^* dl/dT volts

Assuming a value of L as 2.25uH and switching frequency of 20KHz

V_L= 29.97 volts

Energy stored =0.5*Ι_Ί ^Λ 2 =0.9987 joules/ cycle and with 20KHz frequency

Power= 1 *20000 watts =20Kw

Now the energy stored in the inductor need to be transferred to the boost capacitor bank to generate required voltage i.e V_out =600V

V_out= l*dT/C

C=V_out/(l ^* dT) =600/(666.66 ^* 0.00005) * 10 ^Λ 6 uF

C for the current example

Is 55.56 uF

Voltage V_C= 600 V

Energy across boost capacitor

Energy_C=1 Ojoules/cycle

Power stored in capacitor=20000 watts

To ensure a good load regulation ( better than 3%)

The output of boost capacitor is transferred to load/coupling capacitor C_out With value of C as( C_boost/0.03)UF

i.e C_out =55.56/(0.03= 1850 uF

Solar panel : The solar panel under consideration are with following parameters

V_oc= 30Volts (nominal)

l_sc 40 to 1 000 amps (typical)

This is very normal for concentrated solar photovoltaic The main criteria for power transfer from solar energy to electrical energy, apart from concentration of light intensity, the series (sheath) resistance have to be maintained at low values and shunt resistance need to be maintained at high value.

SWITCH MODE SUPER CAPACITORS:

The switch mode super capacitors utilize the features of high capacitance value limited by the allowable voltage. The super capacitor banks / modules are plugged on to the solar panels array of solar cells for charging purposes with a control on buck / boost mode. These super capacitors are connected in series to transport it to other super capacitor reservoir which synthesizes the single stage phase locked switched grid tie inverters with ZVS/ZCS topology.

With the limitation of usage of super-capacitor with allowable voltage is approximately 2.7V hence array of solar cells (each of .5 V )are connected in series to generate 2.7V and these modules are also connected in both series and parallel mode to achieve required voltage and energy transfer in the form of current to the grid tie inverters. These capacitors are embedded in solar panel itself with adequate switching mechanisms.

INPUT CONDITIONING AND CURRENT STORAGE SECTION :

The method for collecting power in the , current loop is configured to adjust the inserting of a plurality of switching devices M1 to M4 in series with a solar power generation system and power storage device. The voltage drop across the input terminals of the switching devices, causes supply to the output terminal the possible power available from the regulated voltage drop and the loop current. In particular, the voltage drop across the switching devices is regulated and a feedback circuit for generating an input voltage signal, by a control circuit for controlling the timing of the charging and discharging of the inductor with the input voltage. The adjustment circuit may be a conventional DC-DC converter, or may be a circuit having a plurality of discrete components such as comparators. In one embodiment, the input conditioning device is a DC-DC buck boost converter for adjusting the input voltage using a feedback circuit. In one embodiment, the input DC-DC converter is adapted to maintain a substantially constant voltage across the input terminals. In other embodiments, as it will be collectable power utilized optionally loop current is low, input regulated DC-DC converter, adapted to adjust the voltage across the input terminals according to the input current there. In other embodiments, input regulated DC-DC converter, in order to enable modulation of the current loop by increasing the impedance of the current loop, and further provides a line filtering circuit. As illustrated in Fig 8(b), the input conditioning section, the circuit operates in two modes:

Current storage Mode-:

During the switches M1 and M4 are closed through the inductor, M2 and M3 are open the short circuit current flow through the inductor, hence current is stored in the inductor.

Energy transfer and charge storage mode:

As shown in Fig 8(c), during the switches M 1 and M3 are open and switches M2 and M4 are closed, the current stored in the inductor is transferred to the super capacitor and the energy is stored in the super capacitor.

Booster and charge storage section:

In this section the stored energy in the super capacitor ( high energy stored) is again switched through a inductor converting the stored energy in the super capacitor current storage across the inductor_boost. The current stored in the boost inductor charges a cascaded capacitor bank to the required voltage by using the theory explained in the earlier section. A plurality of sections of boost and charge transfer circuits are used to build the output power with required voltage regulation.

A voltage boost system is configured for smooth converging an output voltage of a voltage booster when feedback controlling the output voltage. The voltage boost system includes a voltage booster to increase an input voltage and generate a boosted output voltage. A feedback control circuit provided is connected to the voltage booster to compare first and second voltages, which are based on either one of an output voltage of the voltage booster and a reference voltage, with a third voltage, which is based on the other one of the output voltage and the reference voltage. The feedback control circuit generates a feedback signal based on the comparison to feedback control the voltage booster. The feedback control circuit maintains the feedback signal at a constant value when the third voltage is included between the first and second voltages.

In another exemplary embodiment and in order to make the system more comprehensive adequate remote monitoring and supervisory control for each unit of power generation and distribution system is interfaced with using wired/wireless SCADA

GRID TIE INTERFACE SECTION

The interface section includes an output network of multilevel inverters configured for interfacing the dc sources to the grid, such that there is an ease of implementation, efficiency, fault-tolerance capabilities, etc. The inverter is composed of N inverter modules that communicate and coordinate in a distributed manner to perform the dc- to-ac energy conversion. The dc sources are the multistage solar power generators and the control software and electronics implement maximum power-point tracking (MPPT) and regulate the panel output voltage using a buck-booster converter. Then, a (2N + 1 )-level modular multilevel inverter is implemented using H-bridges to create a grid-tie connecting the regulated dc output of each buck-boost converter. An inverter module is the complete plant and computer controller consisting of a dc source, its microcontroller and network interface, buck-boost converter, and H- bridge. The modules communicate with one another to ensure they switch at appropriate times to create the ac waveform for the grid that is in frequency, in- phase, and of the appropriate voltage. A distributed identifier algorithm is used by the N microcontrollers to determine the number of inverter modules and the switching time for each said inverter module to minimize total harmonic distortion for the ac grid-tie.

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.