Field of the Invention

The present invention relates to an energy harvesting system. More particularly, but not exclusively, the present invention relates to a system that converts kinetic energy for example from passing traffic (people or vehicles) to generate electricity.

Background

As global energy demands grow, it is becoming increasingly important to reduce negative impact on the environment and in particular to generate electricity without burning fossil fuels.

Many systems exist to generate energy from renewable sources, including solar panel, wind turbines and hydroelectric turbines. However, such renewable sources have limitations as they are reliant on weather patterns or tides. Therefore energy is generated only when such renewable resources are available.

Newer electricity generation systems and methods for converting energy exist. These require continuous passage of people or vehicles and generate electricity by converting kinetic energy from mechanical forces.

Many of these electricity generation systems require the depression of a platform and a pressurised reservoir which may be inefficient.

Other electricity generation systems can have an adverse effect on a vehicle passing over the platform which is especially is undesirable at speed.

Some existing electricity generation systems, which rely on extraction and conversion of kinetic energy, are described below. Whilst many of these systems are operationally successful, none is capable of coping with quiet periods or situations when there is sudden supply demand placed on them.

Prior Art

United States patent number US 4739179 A (STITES) discloses a system for generating power by vehicular movement.

United States patent number US 4 081 224 A (KRUPP) discloses a series of intermittently operable air pumps.

United States patent number US 4212598A (ENERGY DEV CORP) discloses a plurality of actuator members mounted along the surface of a roadway.

Chinese utility model number CN 205154521 (Gao) model provides a ‘piano type’ deceleration strip that can generate electricity.

German patent application DE 102011116180 (Schlegel) discloses an energy conversion plant with piezoelectric materials arranged under road surfaces, railway tracks, or pedestrian walkways.

UK patent application number GB 2473 198 (Nankali) discloses a platform that is located in a road, walkway or on steps (stairs), so that vehicles or pedestrians press it when passing thereover. Pistons are attached to the platform so that a flow of hydraulic fluid is produced which drives a hydraulic motor or turbine to generate electricity.

Korean patent application number KR 101091097 (Anytech) discloses an electricity generating device which uses a weight of car on a speed bump to generate electricity by operating a generator using pressurised oil in an accumulator.

United States patent application number US 2008224477 (Kenney) discloses a system for electrical power generation which uses vehicle traffic on roadways comprising one or more standard hydraulic cylinders, one or more electro mechanical generators, and one or more hydraulic accumulators coupled to a hydraulic motor.

International patent application number WO 2009037559 (Callegari) discloses a vehicle speed bump which exploits the need to slow down the road traffic in order to produce electrical energy.

International patent application number WO 2015022704 (Jaweed) discloses road traffic deceleration zone electric power generating system.

International patent application number WO 202000992 (Liu Changchun) describes another type of road vehicle power generator.

Many of the aforementioned systems were not suitable for use on road surfaces over which vehicles travelled at speed. One reason was that they presented a raised profile which impinged on tyres of a vehicles and may have damaged vehicle suspensions or tyres.

Another problem with many prior art system is that their hydraulic systems suffered back pressure and so required continual maintenance.

A further problems has been that maintenance of many prior art systems was timely and expensive and often rendered the systems unusable for prolonged periods.

The present invention seeks to overcome these all of the aforementioned problems.

In one embodiment the present invention provides a more efficient means of converting mechanical energy to electrical energy without the need for substantial depression of a deformable surface which may have previously caused a vehicle or person, passing thereover, to deviate. Summary of the Invention

According to a first aspect of the present invention there is provided an energy harvesting system comprising: at least one displaceable platform over which a vehicle or pedestrian passes thereby causing the platform to depress at least one piston-in-cylinder with a return means, the at least one cylinder contains a working fluid whose output is connected to at least one closed circuit containing pressurised working fluid, at least one valve in the at least one closed circuit permits unidirectional fluid flow of the working fluid around the closed circuit; an accumulator is in fluid connection with the at least one closed circuit and is operative to receive pressurised fluid when a divert valve opens to thereby store pressurised fluid to maintain a minimum pressure therein; a hydraulic motor is in fluid connection with the at least one closed circuit, the hydraulic motor receives the pressurised fluid which drives the hydraulic motor and an alternator which is connected to the hydraulic motor to generate electricity; a flywheel is selectively connected to the hydraulic motor by a flywheel engagement means; at least one battery which stores energy; and at least one pressure monitoring sensor is operative to monitor pressure levels of the working fluid in the closed circuit and to send a signal to a processor which transmits commands to a battery control means for the battery to provide electrical energy to an electric motor to drive the hydraulic motor, during periods of low pressure of working fluid, and to the flywheel engagement means, so that the flywheel is operative to store excess kinetic energy during periods of excess pressure of working fluid.

Ideally a programmable logic control (PLC) system monitors when there is no input from actuation of the cylinders that contain the working fluid. The PLC system then sends a signal to a battery control unit, which in turn starts an electric pump to a hydraulic circuit. The hydraulic pump then urges hydraulic fluid around a closed circuit, which drives the alternator. Excess energy is used to drive the flywheel, by way of an electric motor, and this ensures that the alternator continues rotating to generate electric current. The majority of electric current that is generated is transmitted to the grid or used by external loads. A small amount is utilised by an auxiliary system, which ensures the hydraulic pump continues to drive hydraulic fluid around the hydraulic circuit during ambient periods. By operating in this manner the system continues to generate current. The overall performance in efficiency of the alternator is reduced from around 96% to 82%. This still ensures a significant more power output and a greater efficiency than either solar or wind systems.

Another important advantage is that the invention requires significantly less space as much of its infrastructure can be installed underground and so it is less intrusive than comparable solar or wind systems. Ideally a subterranean service chamber is provided which enables access to maintenance personnel for repair and maintenance and to remove serviceable components such as the cassette.

The displaceable platform is arranged in a surface, such as road, pavement, or path so that when a person or vehicle passes over the platform is displaced downwards. In this way the action of vehicles or persons passing over and depressing the platform continues to drive an alternator in order to generate electricity, and excess energy is selectively stored in a flywheel or accumulator in accordance with a control signal from the processor in the PLC control system. So that a passing vehicle, person or even livestock continues to provide the downward forces for activating the pumping action which drives the piston into the cylinder and thereby forces the hydraulic fluid around the closed circuit.

In some embodiments the hydraulic fluid is fed to an accumulator where it is regulated to pass through a hydraulic or pneumatic motor then in turn drives the alternator

Preferably the displaceable platform is arranged flush, or close to, the surface of a road, path, or walkway, and displaced downwards a small amount. The system is preferably embedded within the road surface as a bridging joint. The system ideally includes a plurality of platforms that are each displaceable separately, or a single platform arranged over a number of piston-in-cylinders. Therefore each platform is associated with at least one piston-in-cylinder and may be associated with a plurality of piston-in-cylinders.

Advantageously having one platform associated with a plurality of piston-in- cylinders enables the associated piston-in-cylinders to be simultaneously depressed which significantly increases flow of working fluid through the closed circuit(s).

Furthermore, by having a plurality of piston-in-cylinders depressed simultaneously, only a small displacement of each platform is required to engage the piston-in-cylinders and cause flow of working fluid. In this way the movement of the platform is not significant to a user when passing over the platform.

It is appreciated that the platform and associated piston-in-cylinders may be modular so that a series of modules (platform and one or more piston-in- cylinders) are connected to the system. In this way the system is easy to maintain and repair, can easily be scaled up or down depending upon the location and need, and also the disruption during installation is minimised as access may be maintained over part of a road/pavement/path.

In some embodiments the piston-in-cylinders are grouped into an array or cassette which is removable and replaceable in the event of repair or maintenance. Cassettes or cartridges may comprise a plurality of pressure vessels or reservoirs which are ideally formed from a synthetic plastics material. The synthetic plastics material which is sufficiently sized to or enables the associated piston-in-cylinders to be simultaneously repaired or replaced.

The piston-in-cylinders with return means contain a working fluid that is in fluid connection with one or more closed circuit. In a hydraulic system, preferably the working fluid is a hydraulic fluid such as oil. In a pneumatic system the working fluid is a gas, such as air.

The return means acts to return the piston from the second depressed position to the first position.

The return means may comprise one or more spring associated with the piston, so as to force the piston out of the cylinder, drawing in working fluid to the cylinder from the closed circuit and thereby lift the platform to its first position in readiness for a subsequent depression.

In some embodiments the return means may be a form of pump mechanism that that pushes working fluid through the closed circuit so as to fill the cylinder and force out the piston to a first position.

In a preferred embodiment the system includes a plurality of piston-in-cylinders arranged in a row beneath one or more platform.

In another preferred embodiment the system includes a plurality of piston-in- cylinders arranged in an array beneath one or more of the platforms.

In a preferred embodiment intended for use on a road based system there are 16 piston-in-cylinders. In this way the depression required is typically less than 20mm so the displacement and interruption to a passing vehicle is minimal. Advantageously this means that a vehicle does not need to reduce speed when passing over the platform and is suitable for high speed and high impact road systems.

A single compression of the series of 16 pistons into the cylinders generates greater displacement of fluid through the system, this is critical for the efficiency of the power generation. Ideally the depression of 16 pistons provide 14 litres of hydraulic oil per minute through a closed hydraulic circuit. The alternator is configured to allow it to generate electricity and maintain up to 96% efficiency with a single compression. The configuration and cylinder layout of the road based system provides high flow high efficiency with very little pressure stored or used in the system. All 16 cylinders move substantially simultaneously as the vehicle passes thereover. The system acts in the same way and allows for this consistency with flow to the generation part of the system.

In a preferred embodiment of a pedestrian system the piston-in-cylinder configuration drives fluid at low pressure into a localised accumulator which, when it reaches an optimum pressure, transfer fluid to a central accumulator.

In this embodiment, preferably the pistons may only need to compress from between 6mm to 8mm into the cylinders for significant foot fall in high traffic areas.

Each piston-in-cylinder is in fluid connection with an associated closed circuit. In this way depression of the platform or platforms displaces the working fluid in each cylinder through the closed circuit.

In some embodiments a series of piston-in-cylinders are connected to the same closed circuit. In other embodiments each piston-in-cylinder has a separate closed circuit.

The system has one or more closed circuits that enable pressurised fluid to flow around the system. It is appreciated that only low pressure is required in order to harvest energy.

The closed circuit is a loop that includes an inlet and an outlet to each cylinder of the piston-in-cylinder, so that the action of the piston forces fluid around the loop. Valves are provided to prevent back flow.

The one or more closed circuit is in fluid communication with the hydraulic motor so as to drive the hydraulic motor and thereby an alternator to permit conversion of mechanical energy to electrical energy. Each closed circuit may also be in fluid communication with other optional components, such as a reservoir, filter and/or accumulator.

The closed system includes one or more one-way valves to ensure unidirectional flow. The valves may be on the tube of closed circuit, or at locations where the tube connects to the components. For example, an outlet from a cylinder may have a one-way valve to allow fluid to be pushed out when the piston is depressed and an inlet to the cylinder may have a one-way valve to allow fluid to be drawn in as the piston is returned to the first position by the return means.

The system may also include one or more pressure release valve. In some embodiments the pressure release valve is arranged on the closed circuit, upstream of an accumulator. In some embodiments an accumulator has a pressure release valve. In this way, pressure can be released from the system if a pre-set level is exceeded.

The energy harvesting system has at least one hydraulic motor that is driven by the pressurised fluid. The hydraulic motor is adapted for the working fluid in the closed circuit. For example, the motor may be a hydraulic driven motor or an air pump with a turbine.

Each hydraulic motor is connected to an alternator. The alternator converts mechanical energy from the hydraulic motor to electrical energy. The alternator is a direct drive alternator such as a permanent magnets frameless alternator for direct drive. Advantageously this type of alternator provides minimum resistance so that energy harvesting is maximised. A fully magnetic direct drive alternator (similar to those used in wind energy generation) is used to achieve maximum efficiency).

By using a direct drive alternator with full permanent magnets this allows for very high efficiency rates of 94% under full load, due to the constant high flow rates the system is designed to provide. This type of alternator allows for low revolutions per minute (RPM) and/or a low torque alternator to generate a constant and consistent power output generated by fluid flow due to vehicles or pedestrians displacing the platform.

In some preferred embodiments the system includes at least one accumulator that is in fluid connection with the at least one closed circuit that is operative to receive and store pressurised fluid thereby maintaining a minimum pressure.

In some embodiments there may be a local accumulator associated with each platform and associated piston-in-cylinders, each with a separate closed circuit that connects to a main circuit that is in fluid connection with a main accumulator that is in fluid connection with the hydraulic motor.

Advantageously the inclusion of an accumulator regulates flow if there is less traffic passing over the platform.

Ideally the accumulator includes a pressure release valve in order to be able to regulate pressure, for example if a large volume of traffic passes over the platform in a short space of time.

In some embodiments a second accumulator is provided to store pressurised fluid and release when there is no or only limited traffic, in order to continue conversion of energy.

In a preferred embodiment of the invention the energy harvesting system only requires one vehicle to pass over at regular intervals, such as every 10 minutes, to keep the hydraulic motor in motion and to reach its maximum output. If there are no direct loads passing over the platform the system, because of the pressurised state of the working fluid it continues to generate electricity for around 45 to 60 minutes.

It is appreciated that for high volume areas, such as may be encountered in inner cities, with high levels of regular traffic, there is no requirement for an accumulator as fluid flow will be maintained due to regular passage of vehicles or pedestrians.

In some embodiments the system includes a reservoir that is in fluid connection with the at least one closed circuit. The reservoir may provide a storage volume for when all piston-in-cylinders are depressed and therefore all hydraulic fluid is forced out from the cylinders and through the closed circuits(s). The reservoir may also be provided in case of leakage.

In preferred embodiments the system includes at least one pressure monitoring sensor. In this way the system can monitor the pressure of the working fluid within the system to ensure that it stays within pre-set levels. This ensures that the system operates safely without requirement for manual checks.

There is at least one pressure monitoring sensor which is in communication with a processor (PLC) that receives, and monitors data received from the at least one pressure monitoring sensor. The processor (PLC) is programmed to analyse data received from one or more pressure monitoring sensors to determine the pressure of the, or each, closed circuit and to establish if pressure needs to be released through a press release filed.

In some embodiments the system also includes a transmitter that can send signals to a remote device such as a smartphone or computer to advise a remote user of the status of the system status. In this way the system can be monitored remotely, and maintenance and repair carried out if a problem is detected based on the data received.

In some embodiments the energy harvesting system may include an indicator to show energy generator status. For example, a light indicator may be provided to indicate when the system is generating energy and when the system is not generating energy. This allows someone passing to be able to visually recognise when the system is generating energy. It is appreciated that in some situations this may encourage uses to travel over the platform or platforms in order to generate energy. A preferred embodiment of the invention includes an array of 16 piston-in- cylinders arranged below a single platform with a closed circuit that is in fluid connection with an accumulator. A vehicle passing over the platform therefore depresses all 16 piston-in-cylinders simultaneously.

A system preferably requires 14 litres per minute of flow and 0.2 bar of pressure. Advantageously this means that a push bike can drive the flow of fluid and more significant pressure is not required.

An example calculation is provided to show the output that could be generated.

An average load of midsize vehicle is 1427kg (14000N). Using a preferred piston-in-cylinder, the return means are a spring which requires 2000N of force for spring compression. This results in total load on the 16 pistons of 12000N (750N per piston).

A preferred total pressure of the working fluid is more than 5 bar (equal to 500Kpa) in the closed circuit. This equates to 700Kpa pressure (43Kpa per cylinder).

Using these preferred force and pressure levels an area to be covered by the piston-in-cylinders can be calculated (Area = Force/Pressure).

In a preferred embodiment of the invention includes a hydraulic motor, in which the flow rate and hydraulic motor calculations may be as follows.

The calculations indicate the volume of fluid to be transfer in 2 seconds when area = pd2/4 x stroke length and volume = 175cm ² x 4cm (V= 700cm ³ ).

Taking into consideration the above calculations, a flow rate per second 700/2 = 350cm ³ /second. This is higher that the required value, but this allows for losses and equates to a value Q which is around 22 litres/minute. With a flow rate of 22 litres/minute and a pressure of 700Kpa for 16 cylinders, 300 revolutions per minute (RPM) is the minimum required. However, by operating the RPM value higher this helps maintain energy harvesting to overrun for a longer period of time after a vehicle or person has passed over the platform.

An expected power output based on the above calculations is power = pressure x flow rate (Q). Power = 800Kpa x 22 litres/minute = 280k Watt. According to the above described flow requirements the accumulator uses are suitable for 20 to 30 litres/minute flow rate and suitable for a maximum working pressure is 6 MPA which is the operating limit as for a maximum pressure of 5 to 8 bar as per the load calculations of which specifications given below.

Table 1

The preferred length of the platform in the form of a harvesting system is 300cm. The cylinder portion volume has to be subtracted from this and 100cm more length is added for the tube to compensate the hydraulic fluid cycle including accumulator, hydraulic motor, and as a whole to return the fluid back to the system total length is 800cm.

The table below details this calculation. Tube length calculation:

Table 2

Tube Volume calculations:

Table 3

Cylinder volume calculation:

Table 4

Within the cylinder bore height there is 4.0 cm of stroke length and 1.2 cm is the diameter of the hole from the cylinder and 0.4 cm is clearance volume of the up side and 0.4 cm of the down side. Total system fluid volume calculations:

Table 5

To ensure optimal operation of a system including a reservoir, the fluid present in the reservoir should be more than 5 times of the fluids present in the whole system which compensates the fluids requirements during the operation.

A preferred return spring is durable and suitable for heavy duty application, with expected lifespan of up to 20 years. Ideally the spring may be 3mm to 6mm in length having 3 to 6 coils depending upon the material from which the spring is formed.

Preferred embodiments of the invention will now be described, by way of example and with reference to the Figures in which:

Brief Description of Figures

Figure 1 shows a schematic view of a system;

Figure two shows an overview of a first embodiment of the system;

Figure 3 shows an overview of a second embodiment of the system;

Figure 4 shows an exploded view of the platform and piston in cylinder array; Figure 5 shows a top view was the array shown in Figure 4;

Figure 6A in figure 6 be show views of a piston and cylinder arrangement; Figure 7 shows an example of a multi part platform arranged over a row of piston-in-cylinders;

Figure 8 shows a cross section with the multiplatform shown in figure 7;

Figure 9 shows an isometric view the single platform with a plurality of piston in cylinders arranged beneath;

Figure 10 shows and example of part of the energy harvesting system;

Figure 11 shows an example of a double-conversion universal power supply (UPS);

Figure 12 shows a diagrammatic view of an enhanced universal power supply (UPS);

Figure 13 is a block diagram of a typical hydraulic system;

Figures 14 shows to 28 show detailed system drawings for hydraulics, infrastructure and control of a particularly preferred embodiment of the invneiton with 16 hydraulic cylinders.

Figure 14 shows an overall block diagram of a road-based system;

Figure 15 shows a block diagram of a hydraulic system;

Finger 16 illustrates hydraulic components which are common to each of the 16 cylinder connected to a hydraulic generating system;

Figure at 17 shows a PLC control for the hydraulic system of Figure 15;

Figure 21 shows an overall view of an example of a hump assembly;

Figure 22 shows a part sectional view of the hump assembly of Figure 21 ; Figure 23 shows an overall view of base portions of hydraulic cassettes in Figure 19;

Figure 24 shows a base view of manifolds of the hydraulic cassette;

Figure 25 shows views of a spring rocker which supports surfaces over which vehicles pass;

Figure 26 shows spring mounting assemblies for use with the spring rocker which supports shown in Figure 25;

Figure 27 shows an overall view of a base plate for the hydraulic cassette shown in Figure 19;

Figure 28 is an overall view of a system which includes solar power panels; and

Figure 29 is an overall view of a system which includes wind generators when connected as part of networked system; and

Figure 30 is an overall view of a wind turbine control system.

Detailed Description of Preferred Embodiments

Figure 1 shows a schematic diagram of an example of an energy harvesting system 100. The system 100 has a series of piston-in-cylinders 10 connected to a closed circuit. The closed circuit 20 has unidirectional flow shown in a clockwise direction.

The piston-in-cylinders 10 are arranged under a plurality of platforms 30.

The closed circuit 20 is in fluidic connection with an accumulator 40, a hydraulic motor 50, an alternator 60, a reservoir 70 and a filter 80. The piston-in-cylinders 10 are connected in series to the closed circuit 20 so that depression of anyone of the pistons 11 (see Figure 6B) by the platform 30 forces working fluid clockwise through the closed circuit 20.

An accumulator 60 is located in the closed circuit 20 after the piston-in-cylinders 10. In this way pressurised liquid can be stored and released when pressure falls below a pre-set level.

A hydraulic motor (pump) 50 is arranged on the closed circuit after the accumulator 40. The hydraulic motor 50 is connected to an alternator 60 so as to convert mechanical energy to electrical energy. The hydraulic motor 50 is driven by pressurised fluid flowing through the hydraulic motor.

Fluid exiting the hydraulic motor 50 passes to a reservoir 70 and an outlet from the reservoir continued to a filter.

The reservoir 70 allows for storage of working fluid when all pistons 11 are depressed.

The filter 80 enables any particles in the working fluid to be removed before the working fluid returns to the piston-in-cylinders 10. This prevents damage to the piston-in-cylinders and enables them to have a longer working life.

Figure 2 shows an example of an energy harvesting system 200 for use on a road. The system includes a three of rows of piston-in-cylinders provided under a series of platforms 30.

Four piston-in-cylinders 10 are provided under each platform 30. The platforms 30 are arranged in series. This configuration provides multiple platforms that may be depressed if a person or vehicle passes over the system platforms. As there are a plurality of piston-in-cylinders 10 only a relatively small depression of the platform 30 is required. The piston-in-cylinders 10 are connected to closed circuits 20 which connect to a unit 500 arranged on a side of a road. The closed circuits 20 feed into a local accumulator 40. An outlet 20B from the accumulator feeds pressurised working fluid through the hydraulic motor 50.

A second accumulator 41 is provided. The hydraulic motor 50 is connected to a direct drive alternator 60.

Figure 3 shows a third example of an energy harvesting system 300. A unit 500 houses a hydraulic motor 50 connected to an alternator 60.

Pressurised fluid passes through a closed circuit 20 from the piston-in-cylinders (not visible in Figure 3), that are arranged under the platform 30.

There two tubes connected to the local accumulator 40. One tube 20A receives fluid flow from the piston-in-cylinders to the accumulator 40. The second tube 20B receives fluid flow from the accumulator 40 and returns fluid to the piston- in-cylinders.

A second accumulator 41 is provided. Figures 4 and 5 show of part of an energy harvesting system. The module 400 has a base tray 410 in which an array of piston-in-cylinders 10 is arranged. The base tray 410 receives a lid 420 that covers the piston-in-cylinders 10 and the accumulator 40.

The lid 420 has apertures 425 through which the platforms 30 of each piston- in-cylinder pass through.

A flexible layer 430 is arranged over the lid and platforms 30. The flexible layer is formed from rubber or a hard wearing synthetic rubber. Each piston-in- cylinder 10 has an inlet tube 20A and an outlet tube 20B (see Figure 5) that together form a closed circuit 20. Both the inlet tube 20A and outlet tube 20B for each piston in cylinder are connected to an accumulator 40

Figures 6A and 6B show an example of a piston-in-cylinder 10. The piston 11 is moveable in and out of the cylinder 12. A spring 13 is the return means to return the piston rod 11 after it has been displaced.

Piston seals 14 seal the working fluid in the cylinder 12. When the piston 11 is depressed into the cylinder 12.

The piston-in-cylinder 10 is connected to a Y-piece 15 with two separate channels to permit flow in and out of the cylinder 12. Therefore piston-in- cylinder 10 is associated with its own closed circuit 20.

Figures 7, 8A and 8B show an example of a series of platforms 30 arranged in a line. Each platform 30 is arranged over a series of piston-in-cylinders (not shown in Figure 7). Each platform 30 is sat in a channel 90 and is able to depress a fixed distance before engaging with a surface of the channel 90. This prevents damage to the piston-in-cylinders as compression is limited irrespective of the load passing over the platform. Advantageously this arrangement also limits the movement experience by a person when passing over the platform.

The channel 90 has an Fl-section 91 (see Figure 9A) that receives the platform 30 on and upper face and is received by a rail 92 in the channel 90 on a lower face. It is the engagement of the Fl-section 91 in the slots 92 (see Figure 7) that limits displacement of the platform 30.

The pictured embodiment shows an example with dimensions. The platform 30 in the form of a speed breaker is 3 metres long, with a width of 0.2m and a height of 0.22m.

Figure 10A shows an example of part of an embodiment of the system where fluid inlet pipes 8 feed into an accumulator 1. Moderated fluid then passes from the accumulator 1 to the hydraulic motor 3. The hydraulic motor 3 drives the alternator 4 and electricity generate by the alternator charges a battery 5. The battery 5 is also has a power outlet 6 to enable energy harvested by the system to be transferred to another supply or storage means. It will be appreciated that a bank of fully charged batteries may then be switched into service when power is demanded, for example by households, or when there is a drop or shortfall in supply, thereby avoiding unexpected power outages.

The hydraulic motor 3 also has a fluid outlet pipe 7 that passes to a fluid reservoir 2 and exits the reservoir to return to the piston-in-cylinders.

Figure 10B shows a circuit diagram of the components shown in Figure 10A.

In another embodiment an energy generation and distribution system includes a hybrid inverter.

Figure 11 shows an example of a double-conversion universal power supply (UPS). An AC utility supply is rectified and then routed in parallel with a DC battery. The sum of the two supply lines is then rectified back to AC. This configuration ensures that if there is sufficient energy in the battery the inverter will supply power to a load.

Figure 12 shows an enhanced UPS. The DC battery is now powered in tandem from several additional sources, such as alternators and PV solar, regardless of type of power (AC or DC) or their profile, the alternative power supplies can be safely routed in parallel into the battery. This ensure that the less energy is drawn from the battery by the load. If there is sufficient reserve in the battery the inverter will power the load.

A charge controller prevents the utility from supplying the load or recharging the batteries if there is enough capacity left in reserve;

The cost of energy storage on a macro level (national) tends to be prohibitively expensive and inefficient. It is likely to be so for the foreseeable future, for this reason traditional electricity grids are evolving to incorporate microgeneration and local storage with the grid becoming much more dynamic with energy routed between local stores where the generation is brought much closer to the systems and infrastructure that requires it. To make this possible the need for local storage systems that can utilise many different sources of energy is paramount.

The principle is to treat stored energy as if it were water stored in tank. Water can fill a tank from multiple sources at once and at different rates and times. Whether ‘topping up’ is an intermittent drip or a constant flow, the tank collects and stores water until required. The stored water can then be used to supply multiple end users when required. Water can flow at different rates or be boosted to provide extra pressure where required, all whilst the tank is being filled.

The present invention treats energy in the same way. Just as having a single water tank to store all water collected is impractical and counter-intuitive so is having very few energy stores on the national level. The invneiton therefore enables and encourages smaller distributed local energy reservoirs which harvest additional energy and store this locally in banks of batteries and/or a large mechanical flywheel.

Figure 13 is a block diagram of a typical hydraulic system which is incorporated in the embodiment described above and enables electricity generation, storage, and distribution of energy on a local level that is suitable for a modern national ‘distributed’ or smart grid.

Principle of Operation

A traditional electric inverter converts direct current (DC) into alternating current (AC) to power devices or buildings. The electric inverters can be connected to a transformer to provide a high-voltage (HV) output for connection to the grid. Hybrid inverters expand on this principle to store surplus energy in a local battery and/or flywheel, to provide a temporary store or reserve for periods where there is may be a short-term energy shortfall. More advanced hybrid inverters are dual direction. This means that they can provide an energy supply for a device or building and may also route buffered energy back to the source (typically the grid) for example for so-called peak lopping.

The invention therefore utilises energy conversion technology, traditionally found in uninterruptable power supplies (UPS) systems but dramatically expands their functionality by combining various energy supplies in order to achieve local uninterruptable power supply centres.

Many locations such as data centres or hospitals have a critical requirement for electricity use uninterrupted power supply (UPS) systems which employ a double-conversion process to convert AC mains power into DC for their battery backup systems. Inverter then convert DC into AC to supply equipment. These systems often range from a few kilowatts (for example to maintain a computer system) to several multiple megawatts, which may be required to protect entire buildings or infrastructure.

Due to the critical nature of these installations and operational dependency, replacing them to incorporate renewable energy sources is often challenging and expensive.

One solution that can be retrofitted to any UPS to maintain the original methodology whilst providing the expanded functionality is described below. The system is herein referred to as ‘Engine’ and this is coupled to the primary input of the UPS bus and synchronises with a power supply to enable both supplies to operate in parallel. By supplying enough voltage and current to the input of a load, on an original incomer, the supply capability of the grid is reduced. However, the UPS continues to operate as normal and is unaware of any change to the supply. ‘Engine’ couples to the battery to replace the original charging operation of the UPS, now energy can be directly fed into the battery without any current pulled from a rectifier in the UPS. It can be seen that the charge current drop, despite load on the system or a drained battery, remains constant and from an operational mode the UPS functions as expected.

The rectifier output of the UPS remains unchanged and will supply a critical load as intended. ‘Engine’ can be supplied in modular form to improve an existing UPS system, however, to maximise efficiency a dedicated UPS system ensures maximum yield.

Wind turbines and similar alternator-based generators provide an AC output. These sources are routed via dedicated AC maximum power point tracking (MPPT) devices that manage their operation providing braking and dump-loads are rectified into DC, these are then coupled directly into a battery energy storage system (BESS) of the UPS.

DC-coupled hybrid maximum power point tracking (MPPT) devices take the direct current power sources such as solar and route their energy into the same BESS.

The DC-coupled hybrid inverter which produces the clean single or three-phase power takes the energy from battery energy storage systems (BESS) but can determine how to efficiently utilise its power. Loads can be switched off or current limited if set to be a lower priority.

Finally, an AC rectifier on the input can utilise energy from standard sources such as utility power or other inverters will route their output into the BESS and the output inverter as normal. Traditionally to operate a utility supply in tandem with another energy source would require synchronisation and network protection to ensure that there is not a short circuit or contamination Engine negates this. Whilst these principles individually are not unique, the ability to re-engineer an existing UPS setup without having to replace or modify it, or to have a singular system that can utilise all these sources at once and intelligently manage them moves far beyond what has been possible to date.

Engineered from the ground up to incorporate parallel energy sources in tandem. Whether the source be grid, turbine, biomass, solar, hydrogen or whatever. If it can move electrons then ‘Engine’ is then able to utilise those sources, convert them into DC power coupled to a BESS which in turn can be inverted to AC to provide energy to a load (see Figure 2). The Cube can be expanded for greater loads and has the automation to deskill operation. ‘Engine’ can be retrofitted to an existing UPS or as a modular dedicated system.

A road-based system (RBS) and Engine form part of a kinetic recovery system. Examples of one embodiment of the system is shown in Figures 14 shows to 28 which show detailed system drawings for hydraulics, infrastructure and control of an embodiment of the invention with 16 hydraulic cylinders. These cylinders have a large diameter, which means that event a relatively short vertical displacement will give rise to a significant displacement of internal volume. In practical terms it has been found that the system, when fully operational, is capable of generating 50 kw at around 150 Amps with an internal pressure of around 120 bar and the alternator running at around 600 RPM.

The cylinders convert compressed fluid from the RBS cylinders from vehicle traffic to generate both flow and pressure, each compression is seen as a pulse of fluid movement and force. The RBS is connected to the input of Engine, shown in Figures 14, 21 and 22. This is the hydraulic and electrical generation point, the flow and pressure generated by the RBS is transferred within the circuit to multiple charge accumulators, a hydraulic motor and alternator in its simplest form.

Part of the hydraulics incorporates a recirculation circuit which uses the return from the hydraulic motor to feed back into the pressure line to provide flow to keep the hydraulic motor turning and alternator generating voltage during the dwell cycle of the RBS. A range of flow and pressure metres feed information back to a PLC which determines how best to optimise the use of the recirculation and accumulator circuits based on demand.

A bank of short stroke hydraulic pumps in the ground are forced downwards by moving traffic. This drives fluid into the primary accumulator. The output pressure drives a hydraulic motor which drives a turbine.

The hydraulic return quickly resets the pumps for the next activation.

To overcome the initial torque to spin up the system an electric hydraulic pump will be pulsed from the BESS in the Engine. The flywheel in the turbine will ensure it maintains rotation between activations minimising efficiency losses from additional pulses.

The RBS generator provides the main input to engine for a typical deployment, or can be included in an array of sources to maximise yield of energy.

Sensor senses phase loop controller monitors system recognises no traffic so switches pump to draw current to maintain two-stage pump road based compressor.

1m 600mm houses cylinders in synthetic plastics shroud all moulded as sandwich in base so that quick and easy removal can be carried out for the purposes of repair and maintenance.

Figure 14 shows an overall block diagram of a road-based system and Figure 15 shows block diagram of the hydraulic system of Figure 14. Figure 16 shows the hydraulic components which are common to each of the 16 cylinder connected to a hydraulic generating system.

Figure at 17 shows a programmable logic control (PLC) system for the hydraulic system. Figure 21 shows an overall view of an example of a hump assembly over which vehicles pass and Figure 22 shows a part sectional view of the hump assembly of Figure 21.

Figure 23 shows an overall view of base portions of hydraulic cassettes in Figure 19 include quick release lines and self-sealing valves that enable or pressure vessels. Figure 24 shows a base view of manifolds of the hydraulic cassette which provide a common connection of hydraulic lines to the cassette. Ideally there is at least one pressurised hydraulic cassette which houses replaceable components. These include pressure vessels or reservoirs which optionally include self-sealing valves which isolate the pressure vessels or reservoirs upon removal of the pressurised hydraulic cassette. This speed sup repair and replacement and avoid leakage of hydraulic fluid.

Figure 25 shows views of a spring rocker which supports surfaces over which vehicles pass. Figure 26 shows spring mounting assemblies for use with the spring rocker which supports shown in Figure 25 and Figure 27 shows an overall view of a base plate for the hydraulic cassette shown in Figure 19.

Figure 28 is an overall view of a system which includes solar power panels.

Figures 29A and 29B show overall views of a system which includes wind generators when connected as part of a networked system which is are operative when power requirements exceed 50 kw.

Figure 30 shows an example of an overall system layout for managing pitch angles of wind generators in response to varying windspeeds.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of protection as defined by the claims.