Power generation system

Abstract

A controller for a power generation system comprising: a power outlet, a fuel cell configured to selectively provide power to the power outlet, a battery configured to selectively provide power to the power outlet, and an inverter for converting a DC voltage provided by the fuel cell to an inverter AC voltage for providing to the power outlet. The controller is configured to: receive a system load signal indicative of an amount of power required by an external load connected to the power outlet, receive one or more fuel cell parameters indicative of one or more operating parameters of the fuel cell, and provide a fuel cell power control signal based on the system load signal and the one or more fuel cell parameters, the fuel cell power control signal for setting a control parameter of the fuel cell and / or for setting a control parameter of the inverter.

Description

Technical Field

[0001] The present disclosure relates to a power generation system, and more particularly to a power generation system that uses a fuel cell to supplement or replace grid / land-based supply.

Summary of the Invention

[0002] According to a first aspect of the present disclosure, a controller for a power generation system is provided, the power generation system comprising: a power outlet; a fuel cell configured to selectively provide power to the power outlet; a battery configured to selectively provide power to the power outlet; an inverter for converting the DC voltage provided by the fuel cell into an inverter AC voltage for providing to the power outlet, where the controller is configured to: receive a system load signal representing the amount of power required by an external load connected to the power outlet; receive one or more fuel cell parameters representing one or more operating parameters of the fuel cell; provide a fuel cell power control signal based on the system load signal and the one or more fuel cell parameters, the fuel cell power control signal being for setting control parameters of the fuel cell and / or for setting control parameters of the inverter.

[0003] The controller is further configured to: receive a battery charge signal representing the level of charge of the battery; provide a fuel cell power control signal based also on the battery charge signal.

[0004] The controller is further configured to: determine a fuel cell target value based on the system load signal and the battery charge signal, the fuel cell target current representing the target level of the fuel cell. It is configured to set the fuel cell power control signal based on the fuel cell target value.

[0005] The fuel cell may be configured to supply power to a power outlet and also to charge batteries.

[0006] The power generation system is It may further include a grid supply connector for receiving grid-supplied power, The controller Receiving a grid supply signal that represents the power level of the grid supply, The system is further configured to determine the fuel cell target level based on the grid supply signal.

[0007] The power generation system is It may further include a grid supply connector for receiving grid-supplied power, The controller Receiving a grid supply characteristics signal that represents the characteristics of the grid supply, The system is further configured to provide fuel cell power control signals based on grid supply characteristic signals.

[0008] The grid supply characteristics signal may include a grid supply power level representing the power level of the grid supply. The controller, Based on the system load signal, determine the supply threshold, Comparing the grid power supply level with the supply threshold, If the grid power supply level is below the supply threshold, set the fuel cell power control signal so that the fuel cell provides power to the power outlet, The system may be configured to set a fuel cell power control signal so that the fuel cell does not supply power to the power outlet if the grid supply voltage level is above the supply threshold.

[0009] The controller is The fuel cell target current is determined based on the difference between the grid power supply level and the supply threshold, The system may be configured to set a fuel cell power control signal based on the fuel cell target current when the grid power supply level is below the supply threshold.

[0010] Also, Any controller disclosed herein, Power outlet, fuel cell, Grid supply connector for receiving grid supply voltage, An uninterruptible power supply (UPS) having grid input terminals, power output terminals, and battery connection terminals, The grid input terminal is connected to the grid supply connector. The power output terminal is connected to a power outlet. A power generation system equipped with an uninterruptible power supply (UPS) is disclosed, in which the battery connection terminals are connected to a battery.

[0011] The fuel cell may be configured to supply power to a power outlet.

[0012] The fuel cell may be configured to provide power for charging the battery.

[0013] The power generation system may further include a DC-DC converter connected between the fuel cell and the battery.

[0014] According to further aspects, Power outlet, A fuel cell configured to selectively supply power to a power outlet, battery, Grid supply connector for receiving grid power, An uninterruptible power supply (UPS) having grid input terminals, power output terminals, and battery connection terminals, The grid input terminal is connected to the grid supply connector. The power output terminal is connected to a power outlet, The battery connection terminal is connected to a battery, The UPS is configured to provide the power received at the grid input terminal and / or the battery connection terminal to the power output terminal, There is provided a power generation system including an uninterruptible power supply (UPS) configured to provide the power received at the grid input terminal to the battery connection terminal for charging the battery.

[0015] The power generation system may further include an inverter configured to convert the DC output voltage provided by the fuel cell into an inverter AC voltage, and the inverter is configured to provide the inverter AC voltage to the power outlet.

[0016] The fuel cell may be configured to provide power for charging the battery.

[0017] According to a further aspect, a power outlet, an inverter configured to convert a DC output voltage into an inverter AC voltage, and the inverter is configured to provide the inverter AC voltage to the power outlet, a battery, a grid supply connector for receiving a grid supply voltage, an uninterruptible power supply (UPS) having a grid input terminal, a power output terminal, and a battery connection terminal, where the grid input terminal is connected to the grid supply connector, the power output terminal is connected to the power outlet, the battery connection terminal is connected to the battery, a controller, receiving a grid supply characteristic signal representing a characteristic level of the grid supply voltage, A power generation system is provided, comprising a controller configured to provide an inverter control signal to an inverter based on a grid supply characteristic signal, wherein the inverter control signal is for setting or limiting the supplied inverter power output.

[0018] The power generation system is The fuel cell further comprises a fuel cell configured to provide a DC output voltage. The inverter is configured to convert the DC output voltage provided by the fuel cell into an inverter AC voltage.

[0019] The power generation system is The system may further include a recirculation switch configured to selectively connect the UPS's power output terminals to the UPS's grid input terminals.

[0020] The controller may be configured to operate the recirculation switch based on the grid supply characteristic signal.

[0021] The controller may be configured to operate the recirculation switch so that the recirculation switch connects its power output terminal to the grid input terminal of the UPS.

[0022] The power generation system is The UPS may further include a grid isolation switch configured to selectively disconnect the grid input terminal from the grid supply connector.

[0023] The controller may be configured to operate the grid isolation switch based on the grid supply characteristic signal.

[0024] The controller may be configured to operate the grid isolation switch such that, if the grid supply characteristics signal does not meet the grid supply quality threshold, the grid isolation switch disconnects the UPS's grid input terminal from the grid supply connector.

[0025] The controller is The grid isolation switch may be configured to disconnect the UPS's grid input terminals from the grid supply connector before the controller configures the recirculation switch to connect the UPS's power output terminals to the UPS's grid input terminals.

[0026] The controller is The grid isolation switch may be configured to disconnect the UPS grid input terminal from the grid supply connector, and the recirculation switch may be configured to connect the UPS power output terminal to the UPS grid input terminal, thereby applying a minimum time delay between these two actions.

[0027] The recirculation switch may be configured to selectively connect the protective earth terminal of the power output terminal to the neutral terminal and, optionally, one or more localized earthing rods or similar earthing devices.

[0028] The protective earth terminal of the power output terminal is not selectively connected to the protective earth terminal of the grid input terminal.

[0029] According to further aspects, DC input terminal and reference terminal to which a DC voltage signal is provided during use, Multiple inverters, each inverter having a first inverter input terminal and a second inverter input terminal, An inverter circuit is provided, comprising one diode for each of the multiple inverters. Each of the multiple inverters has its first inverter input terminal connected to a DC input terminal. Each of the multiple inverters' second inverter input terminals is connected to the reference terminal via one of several diodes, such that current is prevented from flowing from the reference terminal to the second inverter input terminal.

[0030] Each of the inverters can convert the DC voltage received between the first inverter input terminal and the second inverter input terminal in order to provide an AC voltage output.

[0031] The inverter circuit may further include a plurality of capacitors, one for each of the plurality of inverters. Each of the plurality of capacitors may be connected between one first inverter input terminal and a second inverter input terminal of each of the plurality of inverters.

[0032] The inverter circuit may further include: a plurality of first inverter input ferrites, one for each of the plurality of inverters; and a plurality of second inverter input ferrites, one for each of the plurality of inverters. Each of the plurality of first inverter input ferrites may be connected in series between one first inverter input terminal and a DC input terminal of each of the plurality of inverters. Each of the plurality of second inverter input ferrites may be connected in series between one second inverter input terminal and a reference terminal of each of the plurality of inverters.

[0033] The inverter circuit may further include one first inverter input ferrite for each of the multiple inverters, one second inverter input ferrite for each of the multiple inverters, one DC input ferrite for each of the multiple inverters, and one reference input ferrite for each of the multiple inverters. For each inverter, one of each first inverter input ferrite may be connected in series between the first inverter input terminal and the first node, one of each DC input ferrite may be connected in series between the first node and the DC input terminal, one of each second inverter input ferrite may be connected in series between the second inverter input terminal and the second node, one of each reference input ferrite may be connected in series between the second node and one anode of each diode, one cathode of each diode may be connected to the reference terminal, and one of each capacitor may be connected between the first node and the second node.

[0034] In a further embodiment, a circuit for a power generation system is provided, which circuit is Grounded output terminal and three active output terminals, Ground terminal and An inverter configured to convert a DC voltage provided by a fuel cell into an inverter AC voltage, wherein the inverter comprises an inverter neutral output terminal and three inverter active output terminals. It is a galvanic isolation circuit, Galvanic isolation circuit, Three primary windings, each connected between one of the three inverter active output terminals and the inverter neutral output terminal. It comprises an isolation transformer including three secondary windings, each connected between three different pairs of active output terminals, The galvanic isolation circuit provides a connection between the ground output terminal and the ground terminal. The galvanic isolation circuit includes an isolation resistor and an isolation capacitor connected in parallel to each other between the inverter neutral output terminal and the ground terminal.

[0035] Isolation resistors and isolation capacitors may provide a high-impedance connection to the inverter's ground.

[0036] The values ​​of the isolation resistors and isolation capacitors are such that the current to ground for a given operating voltage falls below a current threshold.

[0037] According to further aspects, Power outlet, A fuel cell configured to selectively supply power to a power outlet, It is a galvanic isolation circuit, The transmission of power between the fuel cell and the power outlet (which may be directly or indirectly via a battery), A galvanic isolation circuit is configured to provide galvanic isolation between a fuel cell and a power outlet. It is a controller, Receiving a resistance signal representing the resistance between a power transfer node and ground, wherein the power transfer node is a node in the power transfer path between the fuel cell and the isolation circuit, including the fuel cell and the isolation circuit. A power generation system is provided, which includes a controller configured to perform one or more safety actions if the received resistance signal is below a resistance threshold.

[0038] One or more safety actions are, To shut down the fuel cell, To stop supplying hydrogen fuel to fuel cells, Disconnecting the fuel cell from the galvanic isolation circuit, Disconnecting the fuel cell from the power outlet, This may also include isolating power outlets so that they do not receive power from the power generation system.

[0039] The power generation system may include a grid supply connector for receiving grid supply voltage. One or more safety actions may include isolating the grid supply connector so that it does not supply power to the power generation system.

[0040] The power generation system may include an uninterruptible power supply (UPS). One or more safety actions may include disconnecting the UPS from the power outlet.

[0041] One or more safety actions may include stopping the supply of hydrogen fuel to the fuel cell by closing a shut-off valve located in the fuel flow path between the hydrogen source and the fuel cell.

[0042] The shut-off valve may be a normally closed valve.

[0043] The controller is The system may be configured to perform one or more reconnection operations if the received resistance signal, after being below the resistance threshold, returns to exceed the reconnection resistance threshold.

[0044] One or more reconnection actions are, Restarting the fuel cell, To resume the supply of hydrogen fuel to fuel cells, Reconnecting the fuel cell to a galvanic isolation circuit, Reconnecting the fuel cell to the power outlet, This may also include reconnecting the power outlet so that it receives power from the power generation system.

[0045] The power generation system may include a grid supply connector for receiving grid supply voltage. One or more reconnection actions may include reconnecting the grid supply connector so that it supplies power to the power generation system.

[0046] The power generation system may include an uninterruptible power supply (UPS). One or more reconnection operations may include reconnecting the UPS to a power outlet.

[0047] According to further aspects, Power outlet and A fuel cell configured to selectively supply power to a power outlet, A battery configured to selectively supply power to a power outlet, A grid supply connector for receiving grid supply voltage, An uninterruptible power supply (UPS) having grid input terminals, power output terminals, and battery connection terminals, The grid input terminal is connected to the grid supply connector. The power output terminal is connected to a power outlet. An uninterruptible power supply (UPS) has battery connection terminals that are connected to a battery, It is a controller, A power generation system is provided, comprising a controller configured to perform one or more safety actions in response to receiving an alarm trigger signal.

[0048] The controller operates as a safe operation. It may be configured to provide a fuel cell power control signal for reducing the power supplied by the fuel cell.

[0049] The controller may be configured to provide a fuel cell power control signal to reduce the power supplied by the fuel cell to zero.

[0050] The controller may be configured to provide a fuel cell power control signal for gradually reducing the power supplied by the fuel cell.

[0051] The power generation system may include a shut-off valve for stopping the supply of hydrogen fuel to the fuel cell. The controller may be configured, as a safety action, to cause the shut-off valve to stop the supply of hydrogen fuel to the fuel cell.

[0052] The shut-off valve may be a normally closed valve.

[0053] The power generation system may include a galvanic isolation circuit configured to transmit power between the fuel cell and the power outlet, and to provide galvanic isolation between the fuel cell and the power outlet. The controller is configured, as a safety feature, to disconnect the fuel cell from the galvanic isolation circuit.

[0054] The power generation system may include a fuel cell isolation switch for selectively connecting / disconnecting the fuel cell to / from a power outlet. The controller may be configured, as a safety operation, to operate the fuel cell isolation switch to disconnect the fuel cell from the power outlet.

[0055] The power generation system may include a power outlet isolation switch for selectively connecting / disconnecting power outlets from the UPS and / or fuel cell. The controller may be configured, as a safety feature, to operate the power outlet isolation switch so that the power outlets do not receive power from the power generation system.

[0056] The power generation system may include a grid isolation switch for selectively connecting / disconnecting the grid supply connector to / from the UPS. The controller may be configured, as a safety feature, to operate the grid isolation switch so that the UPS does not receive power from the grid supply connector.

[0057] The controller may include one or more relays configured to perform one or more safety actions. The one or more relays may be hardwired to one or more actuators configured to implement the safety actions. The one or more actuators may include shut-off valves, fuel cell isolation switches, power outlet isolation switches, and grid isolation switches.

[0058] The power generation system may further include a user interface that can be operated by the user to provide an alarm trigger signal to the controller.

[0059] The user interface may include a remote emergency stop button from the power generation system, and / or the user interface may include a local emergency stop button to the power generation system, and / or the user interface may be configured to wirelessly provide an alarm trigger signal to the controller.

[0060] The power generation system may include a transport container housing a fuel cell, batteries, and a UPS. The user interface may include either or both an emergency stop button inside the transport container and an emergency stop button outside the transport container.

[0061] The power generation system may further include a sensor configured to provide an alarm trigger signal. Smoke detectors associated with the power generation system, Heat detectors associated with the power generation system, Gas detectors associated with the power generation system, The power generation system may include one or more of the following: an airflow sensor for sensing airflow in the fuel cell compartment of the power generation system.

[0062] The controller is Receiving one or more system parameters that represent one or more operating parameters of a power generation system, It may be configured to generate an alarm trigger signal based on one or more system parameters.

[0063] One or more operating parameters of a power generation system may include one or more fuel cell parameters that represent one or more operating parameters of a fuel cell.

[0064] According to further aspects, A container with internal volume (optionally a transport container), A fuel cell compartment is a portion of the internal volume defined by one or more fuel cell partitions within a container, The fuel cell located in the fuel cell compartment, A battery compartment is a portion of the internal volume defined by one or more battery partitions, The battery located in the battery compartment, The fuel cell compartment is separated by one or more fuel cell partitions. A control compartment, which is part of the internal volume, is separated from the battery compartment by one or more battery partitions. Outflow vent and, A power generation system is provided, comprising a fan configured to reduce the air pressure in the fuel cell compartment so that air is drawn through the battery compartment and the fuel cell compartment and exits the container through an outlet vent.

[0065] The spill vent may be located within the outer wall of the container. The spill vent may be located within the outer wall of the container that defines the wall of the fuel cell compartment.

[0066] The power generation system may further include inlet vents on the outer wall of the container. Fans may be configured to draw air from outside the container into the battery compartment and fuel cell compartment through the inlet vents.

[0067] One or more battery partitions may be generally parallel to the bottom wall of the container and may include raised-floor battery partitions spaced apart from the bottom wall, thereby defining the battery compartment between the raised-floor battery partitions and the bottom wall of the container.

[0068] The inflow vent may be located on the exterior wall that defines the battery compartment.

[0069] One or more fuel cell partitions may be generally parallel to the side walls of the container and may include inner wall partitions spaced apart from the side walls, thereby defining the fuel cell compartment between the inner wall partitions and the side walls of the container.

[0070] The outflow vent may be located on the outer wall that defines the fuel cell compartment.

[0071] The outflow vent may optionally be located near the ceiling, in the upper region of the exterior wall.

[0072] The fan may be configured to blow air out of the container through an outlet vent, thereby reducing the air pressure in the fuel cell compartment and the battery compartment.

[0073] One or more battery partitions may include raised-floor battery partitions that are generally parallel to the bottom wall of the container and spaced apart from the bottom wall, thereby defining a battery compartment between the raised-floor battery partitions and the bottom wall of the container. One or more fuel cell partitions may include inner wall partitions that are generally parallel to the first side wall of the container and spaced apart from the first side wall, thereby defining a fuel cell compartment between the inner wall partitions and the side wall of the container. The container may have a ceiling, and the inner wall partitions may extend between the ceiling and the raised-floor battery partitions.

[0074] The raised floor battery partition may extend between the second side wall, which is on the opposite side of the first side wall, and the inner wall partition.

[0075] The control compartment is UPS and Controller and One or more relays, One or more switches, Galvanic isolation circuit and Inverter and Smoke detectors / alarms, Heat detectors / alarms, Gas detectors / alarms, It may house one or more of the following: an oxygen monitoring system, etc.

[0076] The power generation system is An internal partition that partially defines a fuel cell compartment and also partially defines a battery compartment, The design may further include internal vents in the internal partitions that allow air to flow between the battery compartment and the fuel cell compartment.

[0077] The internal partition may be in the same plane as the raised-floor battery partition.

[0078] According to further aspects, Containers and The fuel cell in the aforementioned container, A hydrogen flow control valve (which may be for reducing the hydrogen pressure before hydrogen is supplied to the fuel cell) is located in the conduit between the hydrogen supply source outside the container and the fuel cell, A power generation system is provided, comprising an inert gas control system configured to operate a hydrogen flow control valve.

[0079] The hydrogen flow control valve may be located outside the container.

[0080] The hydrogen flow control valve may be a normally closed valve.

[0081] According to further aspects, Containers (optional, including transport containers), The control compartment, which is part of the container's internal volume, A fuel cell compartment located within the container footprint and separated from the control compartment by one or more airtight fuel cell partitions, The fuel cell located in the fuel cell compartment, A battery compartment is a portion of the internal volume of a container defined by one or more battery partitions, The battery located in the battery compartment, A power generation system is provided, comprising a fan configured to draw air from the battery compartment into the fuel cell compartment.

[0082] The fuel cell compartment may be open to the atmosphere.

[0083] The fan may be configured to reduce pressure in the battery compartment.

[0084] The power generation system may further include an internal partition that partially defines a fuel cell compartment and also partially defines a battery compartment. A fan may be located within the internal partition.

[0085] The internal partition may be in the same plane as one of the airtight fuel cell partitions.

[0086] The power generation system may further include an outlet vent on the outer wall of the container defining the fuel cell compartment. The outlet vent may be located in the uppermost region of the fuel cell compartment.

[0087] The power generation system may further include a ceiling within the fuel cell compartment, which is angled such that the ceiling defines a surface that extends upward toward an outflow vent.

[0088] The power generation system is A hydrogen flow control valve (optionally for reducing the hydrogen pressure before hydrogen is supplied to the fuel cell) is located in the conduit between the hydrogen source and the fuel cell, The system may further include an inert gas control system configured to operate a hydrogen flow control valve.

[0089] The hydrogen flow control valve may be located within the container's footprint.

[0090] The hydrogen flow control valve may be a normally closed valve.

[0091] The power generation system may further include inlet vents on the outer wall of the container. Fans may be configured to draw air from outside the container into the battery compartment through the inlet vents.

[0092] One or more battery partitions may be generally parallel to the bottom wall of the container and may include raised-floor battery partitions spaced apart from the bottom wall, thereby defining the battery compartment between the raised-floor battery partitions and the bottom wall of the container.

[0093] The inflow vent may be located on the exterior wall that defines the battery compartment.

[0094] One or more airtight fuel cell partitions may be generally parallel to the second side wall of the container and spaced apart from the second side wall, thereby defining a control compartment between the inner wall partition and the second side wall of the container.

[0095] One or more battery partitions may be generally parallel to the bottom wall of the container and spaced apart from the bottom wall, thereby defining a battery compartment between the raised battery partition and the bottom wall of the container. One or more airtight fuel cell partitions may be generally parallel to the second side wall of the container and spaced apart from the second side wall, thereby defining a control compartment between the airtight inner wall partition and the second side wall of the container. The container may have a ceiling. The airtight inner wall partition may extend between the ceiling and the raised battery partition.

[0096] The raised floor battery partition may extend between the second side wall and the inner wall partition.

[0097] The control compartment may house one or more of the following: a UPS, a controller, one or more relays, one or more switches, a galvanically isolated circuit, an inverter, a smoke detector / alarm, a heat detector / alarm, a gas detector / alarm, and an oxygen monitoring system.

[0098] According to further aspects, A container with internal volume (optionally a transport container), A fuel cell compartment is a portion of the internal volume defined by one or more fuel cell partitions within a container, The fuel cell located in the fuel cell compartment, A battery compartment is a portion of the internal volume defined by one or more battery partitions, The battery located in the battery compartment, A control compartment which is part of the internal volume, The fuel cell compartment is separated by one or more fuel cell partitions, A control compartment, separated from the battery compartment by one or more battery partitions, A power generation system is provided, comprising one or more burst panels on the outer wall or ceiling of a container.

[0099] The burst panels may be configured to be removable from their respective frames on the outer wall or ceiling of the container in response to a rapid increase in air pressure inside the container.

[0100] At least one of the burst panels may be located on the outer wall or ceiling of the container defining the fuel cell compartment.

[0101] At least one of the rupture panels may be located on the outer wall or ceiling of the container defining the control compartment.

[0102] At least one of the burst panels may be located on the ceiling of the container.

[0103] At least one of the burst panels may have one edge that is more firmly secured to the container than the other edges of the burst panel.

[0104] According to further aspects, Containers (optional, including transport containers), The fuel cell located inside the container, A fuel cell cooling loop for removing heat from the fuel cell, A power generation system is provided that includes a heat exchanger for transferring heat from a fuel cell cooling loop, so that it can be used to provide services for localized applications requiring heat.

[0105] Local applications may include one or more of the following: providing a hot water source, providing heating, and providing heating to one or more processes.

[0106] The power generation system may further include an additional cooling loop to receive heat from the fuel cell cooling loop through a heat exchanger. The additional cooling loop may be configured to selectively heat water in a water tank so that it can be provided as a hot water source.

[0107] The power generation system may further include one or more valves in an additional cooling loop that are operable to selectively direct fluid to the additional cooling loop in order to heat the water in the water tank.

[0108] The power generation system may further include a heat removal component that selectively transfers heat from the fluid in an additional cooling loop to the atmosphere. The heat removal component may include a radiator and a fan. The heat removal component may be configured to activate automatically when the temperature of the fluid in the additional cooling loop exceeds a predetermined set value.

[0109] Hereinafter, one or more embodiments will be described only illustratively with reference to the attached figures. [Brief explanation of the drawing]

[0110] [Figure 1] An overview of one embodiment of the power generation system is shown. [Figure 2] A schematic diagram of an exemplary embodiment of a power generation system is shown. [Figure 3] Figure 2 shows a simplified diagram of some of the features of the power generation system. [Figure 4] This shows a power generation system similar to the power generation system in Figure 3. [Figure 5] Here is another example of a power generation system in which a fuel cell provides the electricity to charge a battery. [Figure 6] Here is another example of a power generation system, which is a more detailed illustration of the system shown in Figure 5. [Figure 7] Figure 2 shows an exemplary implementation of a circuit that may be used to control the recirculation switch and grid isolation switch. [Figure 8]This specification describes an inverter circuit that enables the use of multiple inverters in an array having a common high-power DC supply, such as that provided by the hydrogen fuel cell described herein. [Figure 9] This diagram shows a circuit for providing galvanic isolation between the AC component and the high-voltage DC fuel cell supply in a power generation system. [Figure 10] Here is another example of a power generation system. [Figure 11] A cross-sectional view of another example of a power generation system is shown. [Figure 12a] A longitudinal cross-sectional view of another example of a power generation system is shown. [Figure 12b] Figure 12a shows a side cross-sectional view of the power generation system, passing through the fuel cell compartment. [Figure 13] A schematic example of a fuel cell cooling circuit is shown below. [Modes for carrying out the invention]

[0111] This disclosure relates to a power generation system that is an environmentally friendly alternative to diesel generators. The power generation system uses a hydrogen fuel cell to supply power to applications where reliable grid / onshore power is unavailable or may be insufficient. Beneficially, no harmful emissions are produced when the hydrogen fuel cell generates power, and therefore the use of the power generation system disclosed herein can be used in clean air zones and can meet industry targets related to emissions.

[0112] As will be discussed in detail below, the power generation systems can be supplied as standard shipping containers so that they are transportable and can easily replace diesel generators. The power generation systems described herein may be particularly suitable for meeting short-term power requirements for festivals or events, for example. These power generation systems can also be used to provide temporary electric vehicle (EV) charging in parking lots. Furthermore, these power generation systems can be used to provide on-site power generation to support the sustainable construction industry.

[0113] Figure 1 shows an overview of one embodiment of the power generation system 100. As will be understood from the following description, the power generation system 100 can be considered a zero-carbon, transportable hydrogen fuel cell off-grid high-power and heat generation system.

[0114] The power generation system 100 includes a shipping container 101, which may be a standard shipping container 101, to allow for convenient transport of the power generation system 100 using known transport methods (such as articulated trucks) to locations where additional or alternative power supplies are needed. For example, the shipping container power generation system 100 may be a 20-foot (approximately 6.1m) portable shipping container. As can be seen from Figure 1, most of the components of the power generation system 100 in this example are located inside the shipping container 101. Those components outside the shipping container 101 can be easily removed for transport and then reinstalled when the power generation system 100 is back in its original location.

[0115] The power generation system 100 includes a hydrogen fuel cell 102, which may be provided as a stack of fuel cells to provide a voltage level sufficient for the intended use of the power generation system 100. The fuel cell 102 can provide high-voltage DC current generation. In this example, the fuel cell 102 is provided in a fuel cell compartment 108 (which may be considered a gas safe room). The fuel cell compartment 108 is a defined volume within the transport container 101, defined by an internal wall 107 that separates the gas fuel cell compartment 108 from the rest of the internal cavity of the transport container 101. As will be discussed in detail below, the fuel cell compartment 108 is provided as a safety feature to ensure that in the event of a hydrogen leak from the fuel cell 102, the hydrogen is discharged outside the transport container 101 and is not exposed to any potential ignition source.

[0116] The power generation system 100 also includes one or more batteries, in this example, multiple batteries 103. As will be discussed in detail below, the batteries 103 may be used to complement the power provided by the fuel cell 102, or to temporarily provide power in place of the fuel cell 102. Additionally, the fuel cell 102 can be used to charge the batteries 103.

[0117] Although not visible in Figure 1, the power generation system 100 also includes a connection to onshore / grid power if onshore / grid power is available. Such onshore / grid power can be supplemented by fuel cells 102 and / or batteries 103. Furthermore, fuel cells 102 and / or batteries 103 can be used as a backup to the onshore / grid power.

[0118] Advantageously, the power generation system 100 can be used to provide an uninterruptible power supply (UPS), which can be facilitated by the fact that the power generation system 100 can be powered by a fuel cell 102 and / or a battery 103, and in some examples further by onshore / grid power. Furthermore, any locally generated electricity (by the fuel cell 102) produces no emissions whatsoever.

[0119] As shown in Figure 1, the power generation system 100 includes a power outlet 104 used to utilize the electricity provided by the power generation system 100. In the drawing, the power outlet 104 is identified as an electrical connection because it provides electrical contacts / sockets where the power generation system 100 is located. The power outlet 104 is accessible from the outside of the shipping container 101 and is provided as part of the UPS (uninterruptible power supply) and HV (high voltage) electrical cabinet 110.

[0120] In one implementation, the power generation system 100 shown in Figure 1 can provide 250 kVA of standard three-phase 400V critical power backed up by an integrated 216 kWh battery system. In this way, 250 kW of off-grid energy can be provided. Furthermore, by combining multiple power generation systems 100, a sufficiently resilient system can be provided that can supply up to 2 MW.

[0121] Other features of Figure 1 will be explained in more detail below.

[0122] It will be understood that any instance of a current signal, voltage signal, or power signal described herein may instead be implemented as a signal representing one of the other two parameters. For example, when a current signal is described, a power signal may be used instead by assuming that the voltage is constant.

[0123] control system Figure 2 shows a schematic diagram of an exemplary embodiment of the power generation system 200 and is used, in particular, to illustrate how the power generation system 200 can be controlled.

[0124] Figure 2 shows a power generation system 200 including a fuel cell 202 (receiving hydrogen from a hydrogen fuel source 206) and batteries 203 (exemplified as a battery array). Figure 2 also shows a power outlet 204 (labeled as a local power source) and an optional grid supply connector 211 for connecting to an input grid / onshore power source.

[0125] In this example, the power generation system 200 includes an inverter 214 that converts the DC voltage provided by the fuel cell 202 into an inverter AC voltage for supply to the power outlet 204.

[0126] Controller 212 is shown in Figure 2, and in this example, it is implemented as a programmable logic controller (PLC). It will be understood that the functionality of controller 212 may be provided by a single component or by multiple distributed components. In some examples, an uninterruptible power supply (UPS) 216 may provide some of the control functions described below.

[0127] Herein, various modes of control over the power generation system 200 are described, and how the power generation system 200 can be used to regulate and maintain a reliable uninterruptible power output at the power outlet 204. Advantageously, the power generation system 200 includes functionality to increase the power and reliability of the available grid / onshore supply.

[0128] Figure 3 shows a power generation system 300 that has roughly the same functionality as some of the features of the power generation system in Figure 2. The components of Figure 3, which are also shown in the previous figure, are given corresponding reference numbers in the 300s.

[0129] The power generation system 300 in Figure 3 includes a power outlet 304 that provides output power from the power generation system 300. In this example, AC power outlets 304' and DC power outlets 304'' are provided, which may be collectively referred to as power outlet 304. As shown above, power outlet 304 may include multiple electrical sockets that can be used to receive power from the power generation system 300.

[0130] The power generation system 300 also includes a fuel cell 302 that can selectively supply power to a power outlet 304. The fuel cell 302 can supply power and can selectively supply power in the sense that it can be controlled so that at any given time, the fuel cell 302 is either supplying power to the power outlet 304 or not supplying power to it. In Figure 3, the fuel cell 302 is shown as being able to supply power to a DC power outlet 304''. Additionally, the fuel cell 302 can supply power to an AC power outlet 304'' via an inverter 314. The inverter 314 converts the DC voltage supplied by the fuel cell 302 into an inverter AC voltage for supply to the outlet 304. In Figure 2, the fuel cell is also shown as being able to supply power directly to the power outlet. In other examples such as Figures 5 and 6, the fuel cell 302 can supply power to the power outlet 304 indirectly, for example, by charging a battery that supplies power to the power outlet 304.

[0131] Figure 3 also shows a battery 303 that can selectively supply power to the power outlet 304 (either an AC power outlet 304' or a DC power outlet 304''). It will be understood that the battery 303 may be supplied as a battery array, as shown in Figure 2. In this example, the battery 303 is shown as supplying power directly to the power outlet 304. However, as will be understood from the description of other examples in this specification, in some examples the battery 303 can supply power to a UPS, and the UPS supplies power to the power outlet 304.

[0132] Figure 3 also shows the controller 312. The controller 312 receives a system load signal 317 representing the amount of power required by an external load connected to the power outlet 304. Such a system load signal 317 may be provided by a load meter (shown in Figure 2 by reference numeral 215) that monitors the load at the power outlet 304. The system load signal 317 can provide values ​​in volt-amperes, which is a suitable unit for all AC loads and power conditions. Volts may be used for the battery charge level. The fuel cell load may be regulated by a DC ampere current.

[0133] The controller 312 also receives one or more fuel cell parameters 318 representing one or more operating parameters of the fuel cell. The fuel cell parameters 318 may include fixed fuel cell parameters representing fixed / non-variable parameters of the fuel cell 302. Examples of such fixed fuel cell parameters include: ●Maximum current rating, which represents the maximum current level that can be provided by fuel cell 302. ●Minimum current rating representing the minimum current level that can be provided by the fuel cell 302. For example, if the fuel cell 302 does not provide the minimum current level, the fuel cell 302 may shut down: ●Minimum hydrogen supply pressure (Bar) and ● Maximum refrigerant temperature (°C).

[0134] The fuel cell parameter 318 may also include a detected fuel cell parameter that represents a detected / variable parameter of the fuel cell 302. Examples of such detected fuel cell parameters include: ●Fuel cell temperature, which represents the temperature of the fuel cell, such as the temperature of the refrigerant in the internal refrigerant loop. ● Fuel cell voltage, which represents the voltage level provided by the fuel cell. ● Fuel cell current, which represents the level of current supplied by the fuel cell. ●Hydrogen supply pressure, which represents the detected value of hydrogen supply pressure, and ●In the example in Figure 2, one or more fault signals, indicated by reference numeral 213, represent fault signals transmitted by the fuel cell controller.

[0135] Next, the controller 312 can provide a fuel cell power control signal 319 based on the system load signal 317 and one or more fuel cell parameters 318. For example, it can ensure that any detected fuel cell parameter does not exceed a corresponding threshold or limit defined by a fixed fuel cell parameter. The fuel cell power control signal 319 is for controlling the power drawn from the fuel cell 302. As shown in Figure 3, the fuel cell power control signal 319 may be provided to the fuel cell 302 or the inverter 314. In this way, the fuel cell power control signal 319 may be for setting control parameters of the fuel cell 302 or the inverter 314. The fuel cell power control signal 319 may be configured to do the following: ● Control the supply of hydrogen fuel to the fuel cell 302, and / or ● Reduce the load on inverter 314.

[0136] Therefore, advantageously, the controller 312 can control the power drawn from the fuel cell 302 so that the power available in the power outlet 304 is sufficient to power the load connected to the power outlet 304.

[0137] In this example, the controller 312 also receives a battery charge signal 321 representing the charge level of the battery 303. The battery charge signal 321 may be provided as a direct measurement of the voltage of the battery 303, or, in examples including a UPS, may be provided by the UPS. Thus, the controller 312 may also provide a fuel cell power control signal 319 based on the battery charge signal 321.

[0138] For example, the controller 312 can determine the fuel cell target current based on the system load signal 317 and the battery charge signal 321. In one application, the battery charge signal 321 may represent a voltage that determines the charge level of the battery 303. In this way, the fuel cell target current represents a target current level for the fuel cell 302 such that the power generation system 300 can supply power to the power outlet 304 that is sufficient to serve the load and also charge the battery 303. The controller 312 can then set the fuel cell power control signal 319 based on the fuel cell target current. In the example in Figure 3, the fuel cell 302 can complement the grid supply voltage so that the battery 302 can be charged (as shown in Figure 4).

[0139] It will be understood that the fuel cell target current is just one example of a fuel cell target value. Other examples of fuel cell target values ​​include fuel cell target power and fuel cell target current. In the various examples disclosed herein, when one example of a fuel cell target value is described, it will be understood that one of the other two examples of fuel cell target values ​​may be used instead.

[0140] In this example, when the fuel cell 302 and inverter 314 directly supply AC power to the power outlet 304, the controller 312 controls the power drawn from the inverter 314 so that it is sufficient to cover the load and charge the battery 303. This can be implemented by setting the fuel cell target current based on the system load signal 317 and the battery charge signal 321.

[0141] As shown in Figure 3, the power generation system 300 further includes a grid supply connector 311 for receiving the grid supply voltage. As shown above, advantageously, if the grid supply voltage is unreliable / unstable, such a power generation system 300 can be used to supplement the grid supply voltage or to disconnect and replace the grid supply voltage without interruption.

[0142] In this example, the controller 312 also receives a grid supply signal 322 representing the power level of the grid supply. Such a grid supply signal 322 may be provided by a grid monitor (shown in Figure 2 by reference numeral 223) that monitors the grid supply received at the grid supply connector 311. The grid monitor may be implemented as a phase monitoring relay and / or a voltage monitoring relay. In that case, the controller 312 can also determine the fuel cell target current based on the grid supply signal 322. For example, if grid supply is available, the power generation system 300 may be configured to use the fuel cell 302 only when grid supply power is insufficient (in some examples, with respect to servicing the load at the power outlet 304 and / or charging the battery 303). That is, the power generation system 300 may be controlled so that power received from the grid supply takes precedence over power locally generated by the fuel cell 302. This may be advantageous for maintaining a hydrogen fuel supply.

[0143] Therefore, the controller 312 can determine the target power outlet power by adding the voltage represented by the system load signal 317 to the voltage required to charge the battery 303 (as represented by the battery charging signal 321). The controller 312 can then determine the target fuel cell current based on the difference between the power level of the grid supply (as represented by the grid supply signal 322) and the target power outlet power. If the target power outlet power is greater than the grid supply level, the power generation system 300 requests the fuel cell 302 to supply power so that the load connected to the power outlet 304 is properly serviced and the battery 303 is charged. Otherwise, the grid / onshore supply is considered sufficient and the fuel cell 302 does not need to supply power.

[0144] In another example, the controller 312 may be configured to control the power generation system 300 so that the fuel cell 302 does not need to charge the battery 303. In that case, the controller 312 can determine the fuel cell target current based on the difference between the power level of the grid supply (represented by the grid supply signal 322) and the power represented by the system load signal 317.

[0145] In some examples, the controller 312 may receive a grid supply characteristics signal that represents the characteristics of the grid supply received at the grid supply connector 311. The grid supply characteristics signal can represent one or more of the following: the power level of the grid supply (described above as the grid supply power signal 322), the frequency of the grid supply (which may be implemented as the grid supply frequency signal), and the phase of the grid supply (which may be implemented as the grid supply phase signal). The controller 312 can then provide a fuel cell power control signal 319 based on the grid supply characteristics signal as well.

[0146] In an example where the grid supply characteristic signal includes grid supply power (representing the power level of the grid supply), the controller 312 can determine the supply threshold based on the system load signal 317. For example, the controller 312 can simply set the supply threshold (determined from the system load signal 317) as the power required by the load connected to the power outlet 304. Alternatively, the controller 312 can set the supply threshold as the sum of: (i) the power required by the load connected to the power outlet 304, and (ii) the power required to charge the battery 303 (considered above).

[0147] Next, the controller 312 can compare the grid supply power level with the supply threshold. ●If the grid power supply level 322 is below the supply threshold, set the fuel cell power control signal 319 so that the fuel cell 302 supplies power to the power outlet 304, or ●If the grid power supply level 322 is above the supply threshold, the fuel cell power control signal 319 is set so that the fuel cell 302 does not supply power to the power outlet 304.

[0148] In an example where the grid supply characteristic signal includes a grid supply frequency signal (representing the frequency of the grid supply voltage), the controller 312 can compare the grid supply frequency signal with one or more frequency thresholds to determine whether the grid supply frequency signal is outside the boundary. ●If the grid supply frequency signal is outside the boundary, set the fuel cell power control signal 319 so that the fuel cell 302 supplies power to the power outlet 304 and / or disconnects the grid connector 311 from the power outlet 304, or ●If the grid supply frequency signal is not outside the boundary (i.e., if the frequency is acceptable), the fuel cell power control signal 319 is set so that the fuel cell 302 does not supply power to the power outlet 304, and / or the grid connector 311 is reconnected to the power outlet 304 if it was previously disconnected.

[0149] Controller 312 can function similarly in an example where the grid supply characteristic signal includes a grid supply phase signal (representing the phase of the grid supply voltage). That is, controller 312 can compare the grid supply phase signal with one or more phase thresholds to determine whether the grid supply phase signal is out of bounds. ●If the grid supply phase signal is outside the boundary, set the fuel cell power control signal 319 so that the fuel cell 302 supplies power to the power outlet 304 and / or disconnects the grid connector 311 from the power outlet 304, or ●If the grid supply phase signal is not outside the boundary (i.e., its phase is acceptable), the fuel cell power control signal 319 is set so that the fuel cell 302 does not supply power to the power outlet 304, and / or the grid connector 311 is reconnected to the power outlet 304 if it was previously disconnected.

[0150] In this way, the fuel cell 302 can be controlled to be used to provide power only when the power available at the grid supply connector 311 is insufficient or otherwise unacceptable.

[0151] The controller 312 can further determine the fuel cell target current based on the difference between the grid power supply level 322 and the supply threshold. If the grid power supply level 322 is below the supply threshold, the controller 312 can set the fuel cell power control signal 319 based on the fuel cell target current, that is, to ensure that the fuel cell 302 supplies the appropriate power.

[0152] Some examples of power generation systems disclosed herein may include additional power sources. For example, as shown in Figures 2 and 6, a photovoltaic (PV) array may provide additional power to a power outlet either directly (as shown in Figure 2) or indirectly by charging a battery (as shown in Figure 6). In some examples, the power generation system may provide AC power or DC power to the power outlet 304.

[0153] Figure 4 shows power generation system 400, which is similar to the power generation system in Figure 3. The components of Figure 4, which are also shown in the previous figure, are given corresponding reference numbers in the 400s.

[0154] Figure 4 includes an uninterruptible power supply (UPS) 416 having a grid input terminal 424, a power output terminal 425, and a battery connection terminal 426. The grid input terminal 424 is connected to the grid supply connector so that the grid supply connector receives the grid supply voltage when the grid supply connector is available. The power output terminal 425 is connected to a power outlet 404. The battery connection terminal 426 is connected to a battery 403. This differs from the power generation system shown in Figure 3, where the DC output of the fuel cell and / or battery is directly connected to a power outlet.

[0155] As is known in the art, the UPS 416 provides emergency power (received from the battery 403 in this example) to a load (connected to the power output terminal 425 via a power outlet) when grid power (at the grid input terminal 424) fails. That is, the UPS 416 provides the power it receives at the grid input terminal 424 and / or the battery connection terminal 426 to the power output terminal 425. The UPS 416 can also provide the power it receives at the grid input terminal 424 to the battery connection terminal 426 in order to charge the battery 403 connected to the battery connection terminal 426. Thus, the UPS 416 can provide at least some of the control functionality described herein in relation to how the battery 403 is used to selectively supply power to the power outlet 404.

[0156] In the example shown in Figure 4, the fuel cell 402 supplies power to the power outlet 404 via the inverter 414. This is consistent with the more detailed drawing in Figure 2.

[0157] To manage demand, the UPS416 can use battery 403 (which may be implemented as a battery array) to temporarily adjust power in the following cases: ●Insufficient power available from the grid supply to the grid supply connector 411, ● The fuel cell 402 or inverter 414 is temporarily unavailable, or ●The power drawn from the power outlet 404, depending on the location, exceeds the available power from the fuel cell 402 or from the grid supply at the grid supply connector 411. This may be known as "peak shaving."

[0158] In this example, the inverter 414 may be configured to meet the load demand and battery charging demand of the UPS 416. The controller 412 can monitor this overall demand, and if the fuel cell 402 is overloaded, the controller 412 can send a signal to reduce the inverter output 414. If the demand is not sufficient to meet the minimum load requirement of the fuel cell, the controller 412 can put the inverter into standby mode and temporarily introduce a DC idle load (or shut it off if this time is prolonged). The fuel cell 402 is then restarted as needed.

[0159] Figure 5 shows another example of a power generation system 500 in which the fuel cell 502 provides power to charge the battery 503. Figure 5 shows a power generation system 500 that is similar to the power generation system in Figure 4. Components of Figure 5, also shown in the previous figures, are given corresponding reference numbers in the 500s.

[0160] In Figure 5, the fuel cell 502 selectively supplies power to the power outlet 504 indirectly, in that it is used to charge the battery 503. Next, the battery 503 is connected to the battery terminal 526 of the UPS 516 so that the battery 503 supplies power to the power outlet 504 when the UPS 516 determines that the grid supply voltage is insufficient. In this way, the power generation system 500 can advantageously utilize the well-established control algorithm of the UPS 516 to supply power to the power outlet 504 based on signals received at the grid input terminal 524 and the battery terminal 526. Furthermore, the fuel cell 502 can be controlled to cover the UPS supply requirements by providing sufficient DC power to the battery circuit and to charge the battery 503 as needed, thereby allowing the power generation system 500 to continue supplying power to the power outlet 504 in the event that the battery 503 would otherwise discharge.

[0161] In this way, the UPS 516 can operate effectively from the battery input 503 permanently when there is no grid. The controller 512 can monitor the battery voltage and control the fuel cell 502 so that the controller 512 adds power accordingly to keep the voltage stable (optionally using a DC-DC converter such as the one shown in Figure 6 by reference numeral 631, but not shown in Figure 5). The fuel cell 502 can be controlled to charge the battery 503 to a set voltage that can represent the nominal full charge of the battery 503. In other words, the controller 512 can determine the fuel cell target current based on the battery charging signal 521. For example, the controller 512 can set the fuel cell target current based on the difference between the battery charging signal 521 and the battery full charge threshold level, and then set a fuel cell power control signal to the fuel cell 502 to charge the battery 503 when the battery charging signal 521 is below the battery full charge threshold level.

[0162] Therefore, in Figure 5, the battery 503 can be directly charged by the fuel cell 502. In this way, the fuel cell 502 can charge the battery 503 and also supply power to the power outlet 504 (via the battery connection terminal 526 of the UPS 516).

[0163] Figure 6 shows another example of power generation system 600, a more detailed illustration of the system in Figure 5. Again, the components of Figure 6, also shown in the previous figure, are given corresponding reference numbers in the 600s.

[0164] As can be seen from Figures 5 and 6, since the batteries 503 and 603 can be charged by the DC voltage provided by the fuel cells 502 and 602, an inverter is not required at the output of the fuel cells 502 and 602. As is known in the art, the UPS units 516 and 616 may include inverter functionality to convert the DC voltage provided by the batteries 503 and 603 into an AC voltage suitable for supplying to the power outlets 504 and 604.

[0165] Returning to Figure 2, the UPS has a grid input terminal 224, a power output terminal 225, and a battery connection terminal 226. The grid input terminal 224 is connected to a grid supply connector 211 to receive grid / land voltage supply when available. The power output terminal 225 is connected to a power outlet 204. The battery connection terminal 226 is connected to a battery 203.

[0166] In a manner similar to that described above, the controller 212 receives a grid supply characteristics signal representing characteristic levels of the grid supply voltage, such as the voltage level, frequency, and phase of the grid supply voltage. The controller 212 can then provide an inverter control signal 227 to the inverter 214 based on the grid supply characteristics signal. The inverter control signal 227 is for setting or limiting the supplied inverter power output by specifying the power output of the inverter 214, for example, based on the required power and the power available in the fuel cell 202. Grid synchronization of the inverter may be provided by the existing "grid tie" functionality of the solar inverter.

[0167] When power from the fuel cell 202 becomes available, the UPS output is then used to synchronize an inverter 214 (a grid-tie inverter array in this example) which can convert the DC fuel cell output into an available AC grid supply. Synchronizing the inverter AC voltage with the grid supply voltage in this way allows both the grid and the fuel cell 202 to provide power to the power outlet 204 simultaneously without interfering with each other.

[0168] Furthermore, in the example of Figure 2, the power generation system 200 includes a recirculation switch 228 configured to selectively connect the power output terminal 225 of the UPS 216 to the grid input terminal 224 of the UPS 226 (while simultaneously disconnecting the land / grid input, if present). Selectively connecting the power output terminal 225 to the grid input terminal 224 is entirely counterintuitive to what is taught in the art. A person skilled in the art would expect the UPS 216 to provide the power received at the grid input terminal 224 to the power output terminal 225. If the UPS 216 is used in a conventional manner, there is no reason to connect the power output terminal 225 to the grid input terminal 224, and in fact, a person skilled in the art would expect that doing so would cause the UPS 216 to malfunction, as it would be "chasing its tail." However, when the UPS 216 is used in combination with the fuel cell 202 as described herein, the inventors unexpectedly discovered that there are advantages to using the UPS 216 in this manner, as described below. Therefore, the inverter AC voltage can be recirculated to the UPS input (grid input terminal 224) to form a self-contained island grid supply.

[0169] By recirculating the supply in this manner, the UPS 216 can have the ability to continuously recharge the battery 203 even when grid power is not available at the grid power connector 211. As discussed in detail above, this additional charging power can be registered by the controller 212, and the power provided by the fuel cell 202 can be increased accordingly to account for both the load and battery charging.

[0170] The controller 212 operates the recirculation switch 228 based on the grid supply characteristic signal. For example, the controller 212 can operate the recirculation switch 228 to connect the power output terminal 225 to the grid input terminal 224 when the grid supply characteristic signal exceeds or does not exceed the grid supply threshold (depending on the characteristics). The grid supply threshold can represent the boundary between an acceptable grid supply voltage and an unacceptable grid supply voltage. An unacceptable grid supply voltage may be one that has an excessively low voltage. In this way, the grid supply threshold can be a grid supply voltage threshold.

[0171] Alternatively or additionally, an unacceptable grid supply voltage may be determined by processing a grid supply phase signal representing the phase of the grid supply voltage. Such a grid supply phase signal may be provided by a phase monitoring sensor relay. Such a relay provides the functionality to set limits for overvoltage, undervoltage, phase error, phase loss, voltage imbalance, and neutral wire break, and can then provide an unacceptable grid supply signal if any of the corresponding grid supply characteristic signals exceed any of those limits / thresholds. The controller 212 can then operate the recirculation switch 228 so that it connects the power output terminal 225 to the grid input terminal 224 in response to the unacceptable grid supply signal. In this way, the controller can set an unacceptable grid supply signal to detect a faulty grid.

[0172] It will be understood that the grid supply threshold can be any threshold suitable for identifying unacceptable grid supplies from the grid supply characteristic signal. Regardless of the type of threshold used, if the grid power received at the grid supply connector 211 is insufficient for a significant period and the battery supply is becoming insufficient, the power generation system 200 will automatically disconnect from the grid supply connector 211, start the fuel cell 202, and transition to the isolated supply. Advantageously, the UPS system 216 can stabilize and supplement the grid power in a short period of time.

[0173] Therefore, the inverter AC voltage provided by the inverter 214 provides power to both the power outlet 204 and the grid input terminal 224 when the recirculation switch 228 is closed / conducting. Advantageously, this allows the UPS 216 to continue operating seamlessly, as if grid power were being received at the grid connector 211, for example by charging the battery 203 as needed. In this way, the fuel cell 202 can be considered to take over the role of grid power when grid power is unavailable or otherwise unacceptable.

[0174] Therefore, the examples disclosed herein allow for the use of a hydrogen fuel cell 202 to enable charging of the battery string 203 of the UPS 216, thereby enabling the UPS 216 to reliably and permanently supply power to a location in the absence of a grid or by supplementing an insufficient or unreliable grid. In this way, the UPS 216 is unaware of the presence of the fuel cell 202, and its guaranteed and tested reliability remains unaffected. This can be achieved in two different ways: ●Referring to Figure 2, the fuel cell 202 is controlled to generate more power than is consumed by the power outlet 204 to which it is connected, thereby converting this power independently of the inverter 214 and synchronizing it with the grid. Recirculating this excess power (via the recirculation switch 228) to the grid input terminal 224 of the UPS 216 allows the UPS 216 to manage the battery charging process. ●Referring to Figure 6, the UPS 616 can be seen to have a permanent battery supply at the battery connection terminals, by controlling the fuel cell 602 to generate excess power and inject it directly into the UPS battery circuit 603 using the DC-DC coupling 631, thereby complementing or creating a stable grid.

[0175] The power generation system 200 in Figure 2 further includes a grid disconnect switch 229 that can selectively disconnect the grid input terminal 224 of the UPS 216 from the grid supply connector 211. Again, the controller 212 can operate the grid disconnect switch 229 based on the grid supply characteristic signal. For example, the controller 212 can operate the grid disconnect switch 229 to disconnect the grid input terminal 224 from the grid supply connector 211 if the grid supply characteristic signal exceeds or does not exceed the grid supply threshold (depending on the characteristic). In this way, if the grid supply voltage received at the grid supply connector 211 is deemed unacceptable (because the grid supply voltage does not meet the grid supply threshold), the grid supply connector 211 is disconnected from the grid input terminal 224 of the UPS 216, and the power output terminal 225 is connected to the grid input terminal 224 of the UPS 226. Disconnecting the grid supply connector 211 in this way is advantageous because it prevents unacceptable grid supply supplied to the grid supply connector 211 from interfering with the inverter AC voltage output supplied by the inverter 214, which is now also supplied to the grid input terminal 224 of the UPS 216.

[0176] Beneficially, the controller 212 can configure the grid disconnector 229 to disconnect the grid input terminal 224 of the UPS 216 from the grid supply connector 211 before the controller 212 configures the recirculation switch 228 to connect the power output terminal 225 to the grid input terminal 224 of the UPS 216 (for example, by applying a minimum time delay). In this way, the grid supply voltage and inverter AC voltage provided by the inverter 214 are not provided to the grid input terminal 224 simultaneously, thus further reducing or eliminating the possibility of any interference. In this way, the grid disconnector 229 and the recirculation switch 228 can operate as break-before-make switching operations.

[0177] Figure 7 shows an exemplary implementation of a circuit that may be used to control the recirculation switch and grid isolation switch shown in Figure 2.

[0178] Figure 7 shows a grid supply connector 711, which includes a protective earth (PE) terminal, a neutral terminal (N), and three active terminals (L1, L2, L3). Figure 7 also shows a grid input terminal 724 of the UPS, which has the same terminals as the grid supply connector 711. A grid disconnect switch 729 is connected between the grid supply connector 711 and the grid input terminal 724. As shown, the grid disconnect switch 729 can selectively disconnect the four terminals (L1, L2, L3, and N) of the UPS grid input terminal 724 from the corresponding terminals of the grid supply connector 711. As discussed above, the grid disconnect switch 729 is used to selectively disconnect the grid supply from the UPS, particularly when the grid supply is considered unacceptable.

[0179] Figure 7 also shows the power output terminal 725, which includes a protective earth (PE) terminal and three active terminals (L1, L2, L3). As discussed above with reference to Figure 2, the power output terminal 725 is connected to the power outlet of the power generation system. The power output terminal 725 is also connected to the output of the inverter so that the inverter AC voltage is also present at the power output terminal 725.

[0180] The recirculation switch 728 is connected between the power output terminal 725 and the grid input terminal 724. As shown, the recirculation switch 728 can selectively connect the three active terminals (L1, L2, L3) of the power output terminal 725 to the corresponding terminals of the grid input terminal 724. As considered above, the recirculation switch 728 is used to selectively connect the power output terminal 725 to the corresponding terminals of the grid input terminal 724.

[0181] The recirculation switch 728 can also selectively connect the PE terminal of the power output terminal 725 to the neutral terminal of the grid input terminal 724, and to one or more localized grounding rods (shown in Figure 1 by reference numeral 199 and in Figure 10 by reference numeral 1099), or similar grounding devices. The PE terminal of the power output terminal 725 is hardwired to the PE terminal of the grid input terminal 724. This is discussed in more detail below and illustrated with reference to Figure 10 in relation to a neutral grounding switching system that enables safe switching between the onshore grid and the isolated grid / grounding supply.

[0182] A switching trigger signal 732, schematically illustrated in Figure 7, is used to change the state of the recirculation switch 728 and the grid isolation switch 729 so that the input to the UPS transitions between the grid supply voltage (from the grid supply connector 711) and the recirculation voltage (from the fuel cell). A controller (not shown in Figure 7) may provide the switching trigger signal 732 in any manner described herein, such as when the grid supply characteristic signal does not exceed an acceptable grid supply threshold.

[0183] The circuit in Figure 7 is an implementation of an electrically interlocked timer contactor circuit with guaranteed break-before-make, which is used to ensure that recirculation / island and onshore grid connections are not combined together. Furthermore, there is a built-in delay to prevent sudden transitions between supplies. This also ensures that the UPS is completely disconnected from the onshore grid supply so that the UPS resynchronizes to its own output and inverter when recirculation is combined.

[0184] Figure 8 shows an inverter circuit that enables the use of multiple inverters in an array with a common high-power DC supply, such as that provided by the hydrogen fuel cell described herein.

[0185] The inverter circuit includes a DC input terminal 833 and a reference terminal 834, which provide a DC voltage signal during use. In this example, the DC voltage signal is provided by the fuel cell. However, in principle, the inverter circuit of Figure 8 can be used with photovoltaic cells that provide the DC voltage signal, especially when the DC voltage level is greater than the rating of the individual inverters 835.

[0186] The circuit in Figure 8 includes a plurality of inverters 835. When the plurality of inverters 835 are provided in the manner shown in Figure 8, these inverters can be considered an inverter array. Each inverter 835 has a first inverter input terminal 836 and a second inverter input terminal 837. Each of the plurality of inverters is configured to convert the DC voltage received between the first inverter input terminal 836 and the second inverter input terminal 837 in order to provide an AC voltage output (referred to as inverter AC voltage elsewhere in this document).

[0187] Figure 8 also includes a plurality of diodes 838, one for each of the plurality of inverters 835. The first inverter input terminal 836 of each of the plurality of inverters 835 is galvanically connected to the DC input terminal 833. The second inverter input terminal 837 of each of the plurality of inverters 835 is connected to the reference terminal 834 via one of the plurality of diodes 838, so that current is prevented from flowing from the reference terminal 834 to the second inverter input terminal 837. The diodes 838 can be considered anti-feedback diodes, which are used to generate a common DC rail suitable for connecting the DC voltage provided by the fuel cell to the input terminals of the plurality of inverters 835.

[0188] The circuit in Figure 8 also includes multiple capacitors 839, one for each of the multiple inverters 835. Each of the capacitors 839 is connected between one of the first inverter input terminals 836 and one of the second inverter input terminals 837 of each of the multiple inverters 835.

[0189] This circuit further includes a plurality of first inverter input ferrites 841, one for each of the plurality of inverters 835, and a plurality of second inverter input ferrites 842, also one for each of the plurality of inverters 835. Each of the plurality of first inverter input ferrites 841 is connected in series between one first inverter input terminal 836 and DC input terminal 833 of each of the plurality of inverters 835. Each of the plurality of second inverter input ferrites 842 is connected in series between one second inverter input terminal 837 and reference terminal 834 of each of the plurality of inverters 835.

[0190] Furthermore, this circuit includes one DC input ferrite 843 for each of the multiple inverters 835, and one reference input ferrite 844 for each of the multiple inverters 835. For each of the inverters 835, ●Each of the first inverter input ferrites 841 is connected in series between the first inverter input terminal 836 and the first node 845. ●One of the DC input ferrites 843 is connected in series between the first node 845 and the DC input terminal 833. ●One of the second inverter input ferrites 842 is connected in series between the second inverter input terminal 837 and the second node 846. ●Each of the reference input ferrites 844 is connected in series between the second node 846 and one of the anodes of each of the diodes 838. ●Each of the cathodes of diode 838 is connected to the reference terminal 834. ●One of each of the capacitors 839 is connected between the first node 845 and the second node 846.

[0191] The circuit in Figure 8 provides a capacitive / inductive smoothing circuit that assists in generating a common DC rail from a hydrogen fuel cell DC supply, which is suitable for providing to multiple inverters in an inverter array. This may be particularly beneficial because it can enable commercially available solar inverters that require relatively low-power, independent DC inputs for each inverter to be used with fuel cells that have a single high-power DC output.

[0192] Figure 9 shows the circuit of the power generation system.

[0193] Most commercially available fuel cells require a "floating circuit" to operate, isolated from ground for system safety and reliability, preventing irreparable damage to the fuel cell in the event of insulation loss / failure. However, most UK power distribution systems are grounded at the neutral terminal to prevent the chassis from becoming permanently active in typical overload protection circuits. Therefore, galvanic isolation between the AC components and the high-voltage DC fuel cell supply is necessary for fuel cell operation.

[0194] The circuit in Figure 9 includes a ground output terminal 949 and three active output terminals 951, one for each phase of the three-phase AC supply. The circuit also includes a ground terminal 956.

[0195] The circuit also includes an inverter 935 that converts the DC voltage provided by the fuel cell into an inverter AC voltage. The inverter 935 includes an inverter neutral output terminal 948 and three inverter active output terminals 947.

[0196] Figure 9 shows a galvanic isolation circuit including an isolation transformer. In this example, the isolation transformer is a star-delta transformer, which includes three primary windings 952, each connected between one of the three inverter active output terminals 947 and the inverter neutral output terminal 948, and three secondary windings 953, each connected between different pairs of the three active output terminals 951. The galvanic isolation circuit also provides a galvanic connection between the ground output terminal 949 and the ground terminal 956.

[0197] The galvanic isolation circuit further includes an isolation resistor 955 and an isolation capacitor 954 connected in parallel to each other between the inverter neutral output terminal 948 and the ground terminal 956. The isolation resistor 955 and the isolation capacitor 954 provide a high-impedance connection to ground for the inverter and associated fuel cell. The values ​​of the isolation resistor 955 and the isolation capacitor 954 are such that the current to ground for a given operating voltage is below a current threshold. In this way, advantageously, the current to ground is always well below a level that would cause human discomfort, but low enough to ensure that the common-mode voltage of the galvanically isolated fuel cell circuit remains within known perceptible limits.

[0198] The values ​​of the isolation capacitor 954 and isolation resistor 955 are adjusted to match the interference characteristics of the installed inverter. Exemplary values ​​for the isolation capacitor 954 are at least 10nF, 50nF, 100nF, and 200nF. Exemplary values ​​for the isolation resistor 955 are 1MΩ, 3MΩ, 4.7MΩ, 5MΩ, and 10MΩ.

[0199] Electrical systems Figure 10 shows an example of power generation system 1000. Features of Figure 10 described with reference to previous drawings (particularly Figures 2 and 6) are given corresponding reference numbers in the 1000s.

[0200] The power generation system 1000 includes a power outlet 1004, a fuel cell 1002, and a UPS 1016. The fuel cell 1002 is configured to selectively supply power to the power outlet 1004, as described above. For example, the fuel cell 1002 can directly supply power to the power outlet 1004, or it can indirectly supply power to the power outlet 1004 by charging a battery 1003, which in turn supplies power to the power outlet 1004.

[0201] The power generation system 1000 also includes a galvanic isolation circuit 1057 that can transmit power between the fuel cell 1002 and the power outlet 1004. As described above, this power transmission may be indirect in some examples via the battery 1003. The galvanic isolation circuit 1057 can also provide galvanic isolation between the fuel cell 1002 and the power outlet 1004. As considered above, this galvanic isolation is required for fuel cell operation and can provide important equipment and reliability advantages, along with safety advantages when combined with a ground fault monitoring system.

[0202] In Figure 2, the functionality of the galvanic isolation circuit 1057 is provided by the multi-transformer galvanic isolation block 258 (which is shown in more detail in Figure 9). In addition, the galvanic isolation circuit 1057 provides the functionality of the inverter array 214 in Figure 2, as shown in Figure 10. For this reason, the galvanic isolation circuit 1057 in Figure 10 can be considered to provide AC coupling between the fuel cell 1002 and the power outlet 1004.

[0203] In Figure 6, the functionality of the galvanic isolation circuit 1057 is provided by the DC-DC galvanically isolated coupling array 631. Therefore, the galvanic isolation circuit 1057 in Figure 10 can be considered to provide DC coupling between the fuel cell 1002 and the battery 1003, either further or alternatively.

[0204] Returning to Figure 10, the power generation circuit 1000 includes a controller 1012 that receives a resistance signal 1059 representing the resistance between the power transfer node 1062 and ground 1063. The power transfer node 1062 is a node in the power transfer path (in this example, the DC power transfer path) between the fuel cell 1002 and the isolation circuit 1057, which includes the fuel cell 1002 and the isolation circuit 1057. In this example, the power transfer node 1062 is located between the fuel cell 1002 and the common rail galvanic isolated DC circuit 1064 (which may be implemented as the circuit in Figure 8 in some examples).

[0205] In Figure 10, the resistance signal 1059 is provided by a ground fault relay or ohmmeter 1061 connected between the power transmission node 1062 and ground 1063. In this example, a ground fault monitor 1060 is connected between the ohmmeter 1061 and the controller 1012 to perform any optional processing on the resistance signal 1059 provided by the ohmmeter 1062 before being provided to the controller 1012.

[0206] If the received resistance signal 1059 is below a value that could cause a current harmful to human health to flow to ground, typically below the resistance threshold, the controller 1012 performs one or more safety actions. Non-limiting examples of suitable resistance thresholds include the range of 5,000 to 275,000 ohms, such as 5,000 ohms, 10,000 ohms, 50,000 ohms, 100,000 ohms, 275,000 ohms, or 300,000 ohms. It has been found that if the resistance between the power transmission node 1062 and the ground 1063 drops below a certain level, it is most likely that an undesirable path to ground exists. This should not be the case when the power generation system 1000 is operating correctly, because this part of the system (the fuel cell 1002 and the power transmission path between the fuel cell 1002 and the isolation circuit 1057, including the isolation circuit 1057) should be floating. By monitoring the resistance signal 1059 in this way, the equipment of the power generation system 1000 can be protected, and personnel can be protected from electric shock.

[0207] One or more safety actions may include: ● Shutting down the fuel cell and / or disconnecting the inverter. This safety operation can be performed by the fuel cell controller 1065 in Figure 10, and although the fuel cell controller 1065 is shown separately from the PLC controller 1012 in Figure 10, it can be considered part of the controller. ● To stop the supply of hydrogen fuel to the fuel cell 1002. This safety action may include the controller (PLC controller 1012 in this example) closing a shut-off valve 1066 in the fuel flow path between the hydrogen source 1006 and the fuel cell 1002. This safety action may also be implemented by a relay 1067 (which may be considered more generally to provide part of the controller's functionality) closing the shut-off valve 1066. The relay 1067 is described in more detail below. The shut-off valve 1066 may, advantageously, be implemented as a normally closed valve. This offers a safety advantage in that the fuel supply is cut off when the shut-off valve 1066 is not powered. ● Disconnect the fuel cell 1002 from the galvanic isolation circuit 1057 and / or from the power outlet 1004. This safety action may include the controller (either the PLC controller 1012 or the relay 1067) opening one or more fuel cell isolation switches (not shown) in the galvanic isolation circuit 1057. ● Isolate power outlet 1004 so that it does not receive power from the power generation system 1000. This safety action may include the controller (either PLC controller 1012 or relay 1067) opening a power outlet isolation switch 1068 to disconnect power outlet 1004 from the UPS 1016 and / or fuel cell 1002. ●Disconnecting the UPS1016 from the power outlet 1016 can also be implemented by the controller opening the power outlet disconnect switch 1068 in the embodiment shown in Figure 10. ● Increase the speed of the fans (fans 1172, 172, etc., described below with reference to Figures 11 and 1) that draw air through the fuel cell compartment 1108 and expel it from the container / power generation system through the outlet vent.

[0208] In the example in Figure 10, the power generation system 1000 also includes a grid supply connector 1011 for receiving grid supply voltage, as described above. In this case, one or more safety actions may include isolating the grid supply connector 1011 so that it does not supply power to the power generation system 1000. This safety action may include the controller (either the PLC controller 1012 or the relay 1067) opening the grid isolation switch 1029 to disconnect the grid supply connector 1011 from the UPS 1016.

[0209] If the received resistance signal 1059 returns to above the reconnection resistance threshold after being below the resistance threshold, the controller can perform one or more reconnection operations. It will be understood that the reconnection resistance threshold may be greater than the resistance threshold to provide some hysteresis to its operation. Performing one or more reconnection operations, as will be considered below, allows the controller to return the power generation system to a fully operational mode after the fault that caused the decrease in resistance has been removed.

[0210] One or more reconnection actions may include: ● Restart fuel cell 1002. ●For example, by opening the shut-off valve 1066, the supply of hydrogen fuel to the fuel cell 1002 can be resumed. ● For example, reconnecting the fuel cell 1002 to the galvanic isolation circuit 1067 by closing one or more fuel cell isolation switches (not shown) in the galvanic isolation circuit 1057. ●For example, the fuel cell 1002 is reconnected to the power outlet 1004 by closing the fuel cell isolation switch in the galvanic isolation circuit 1057. ●For example, by closing the power outlet isolation switch 1068, the power outlet 1004 is reconnected so that it receives power from the power generation system 1000. ●For example, by closing the power outlet disconnect switch 1068, the UPS 1016 can be reconnected to the power outlet 1004. ●For example, by closing the grid isolation switch 1029, the grid supply connector 1011 is reconnected so that it supplies power to the power generation system 1000.

[0211] In this way, the AC load can be provided by MCCB (molding circuit breaker) overcurrent protection and neutral ground bonding to prevent electric shock. The fuel cell electrical connection is a floating type that is not grounded, allowing for constant monitoring of ground faults. A ground fault in this circuit can cause the controller to perform a controlled shutdown of the fuel cell, removing the load and protecting equipment and personnel from electric shock. This may include a neutral ground switch schematically shown in Figure 10 by reference numeral 1071, where local neutral grounding is established at the point of switching from grid to island power. This corresponds to the functionality described above with reference to Figure 7.

[0212] A controlled shutdown may involve the controller sending a signal to shut down the fuel cell while the hydrogen fuel supply and fuel cell power are maintained. This may be in contrast to an emergency shutdown, where the fuel cell's power output and power supply are immediately disconnected and the hydrogen fuel supply is disconnected by an external valve. This may only be implemented as part of a potentially very serious safety procedure, as it could damage the fuel cell.

[0213] Here, we describe one aspect of the power generation system 1000 in Figure 10 that is more generally related to receiving and responding to an alarm trigger signal (the resistance signal described above is an example of an alarm trigger signal) in order to protect equipment and personnel.

[0214] One or more of the following features of the power generation system 1000 may be particularly for this embodiment: a power outlet 1004, a fuel cell 1002 configured to selectively supply power to the power outlet 1004, a battery 1003 configured to selectively supply power to the power outlet 1004, a grid supply connector 1011 for receiving grid supply voltage, and a UPS 1016. As described above, the UPS 1016 has a grid input terminal 1024 connected to the grid supply connector 1011, a power output terminal 1025 connected to the power outlet 1004, and a battery connection terminal 1026 connected to the battery 1003. Also, at least the fuel cell 1002, the battery 1003, and the UPS 1016 are housed in a transport container 1001.

[0215] The controller in Figure 10 (which may be a PLC 1012, a fuel cell controller 1065, and / or a relay 1067) is configured to perform one or more safety actions in response to receiving an alarm trigger signal.

[0216] Examples of safety actions that may be performed by the controller include: ● To provide a fuel cell power control signal for reducing the power supplied by the fuel cell 1002 and stopping the fuel cell in a controlled manner. ● The shut-off valve 1066 will stop the supply of hydrogen fuel to the fuel cell and to the container 1002. ● Disconnecting the fuel cell 1002 from the galvanic isolation circuit 1057, which can be achieved by operating a fuel cell isolation switch (which may be located inside the block labeled AC coupling or DC coupling in Figure 10). ● Disconnecting the fuel cell 1002 from the power outlet 1004, which can be achieved by operating the fuel cell disconnect switch to disconnect the fuel cell 1002 from the power outlet 1004. ● Disconnecting the power outlet 1004 from the UPS 1016 and / or fuel cell 1002, which can be achieved by operating the power outlet-isolation switch 1068 so that the power outlet 1004 does not receive power from the power generation system 1000. ● Disconnecting the grid supply connector 1011 from the UPS 1016, which can be achieved by operating the grid isolation switch 1029 so that the UPS 1016 does not receive power from the grid supply connector 1011.

[0217] As shown above, the controller may include one or more relays 1067 configured to perform one or more safety actions. One or more relays 1067 can be considered an electrical safety relay and may be hardwired to one or more actuators configured to implement safety actions. In the example in Figure 10, one or more actuators include a shut-off valve 1066, a fuel cell isolation switch (not shown), a power outlet isolation switch 1068, and a grid isolation switch 1029. One or more relays 1067 can be used to implement safety-critical safety actions, including those that are particularly important for maintaining personnel safety.

[0218] The power generation system 1000 of FIG. 10 includes a manually operable user interface that a user can operate to provide an alarm trigger signal to the controller. The user interface of FIG. 10 includes an emergency stop button 1069 that is local to the power generation system 1000 (e.g., inside the transport container 1001). The user interface of FIG. 10 also includes an emergency stop button 1070 that is remote from the power generation system 1000 (e.g., outside the transport container 1001). As a further example, the user interface can wirelessly provide an alarm trigger signal to the controller in response to, for example, the user actuating a remote emergency stop button 1098. Such a remote emergency stop button 1098 can be provided on a computing device including a portable computing device such as a smartphone, a tablet computer, or a laptop computer.

[0219] As a further example, a sensor can provide an alarm trigger signal. Optionally, the sensor can provide an alarm trigger signal to one or more relays 1067, particularly when the sensor is providing safety-critical information. Examples of suitable sensors include: A smoke sensor / alarm associated with the power generation system 1000 (optionally inside the transport container 1001), A heat sensor / alarm associated with the power generation system 1000 (optionally inside the transport container 1001), and A gas sensor / alarm associated with the power generation system 1000 (optionally inside the transport container 1001).

[0220] As an additional example, an airflow sensor for sensing airflow in a fuel cell compartment or a battery compartment of a power generation system. The airflow sensor can generate an alarm trigger signal if the airflow is potentially insufficient to reliably remove leaked hydrogen. The airflow sensor can directly measure the airflow or measure the air pressure, which can be another way of representing the airflow (due to the difference from the ambient air pressure outside the container). As an even further example, the airflow sensor can measure the operating parameters of a fan used to create an airflow through the fuel cell compartment, as will be discussed in more detail below.

[0221] In some examples, a controller (in this example, the PLC controller 1012) receives one or more system parameters (an example of which is the fuel cell parameters described above) representing one or more operating parameters of the power generation system 1000. The controller can then generate an alarm trigger signal based on the one or more system parameters.

[0222] In this way, an electrical safety system can be implemented as a three-way protection system: ● Actuated manually via emergency stop buttons 1069, 1070, 1098 ● Hard-wired monitoring relays that are automatically actuated using signals from: 〇 Gas detectors, and 〇 Smoke and heat detectors, ● Automatically actuated via a programmable logic controller (PLC) 1012 and software

[0223] This can result in an immediate stop of the system in an emergency.

[0224] Pressing an emergency stop button, or detecting a fatal fire or gas, can result in: ● Disconnection of the grid supply, ● Disconnection of the supply, ● Stopping of the fuel cell, and ● All gas shutdown emergency procedures disclosed herein.

[0225] Furthermore, system parameters can be monitored by the PLC 1012, and if the parameters exceed set limits to protect personnel and equipment, a controlled shutdown of the power generation system 1000 is triggered.

[0226] Gas safety system Figure 11 shows a cross-sectional view of another example of the power generation system 1100. The features of Figure 11 described with reference to the previous drawings are given corresponding reference numbers in the 1100 range. The power generation system 1100 of Figure 11 is used to illustrate various embodiments of gas safety systems.

[0227] The power generation system 1100 includes a container 1101, in this example, a transport container 1101 having an internal volume. The internal volume is subdivided into three compartments: i) a fuel cell compartment 1108, ii) a battery compartment 1178 (also shown in Figure 1 by reference numeral 178), and iii) a control compartment 1177 (also shown in Figure 1 by reference numeral 177).

[0228] The fuel cell 1102 is located within the fuel cell compartment 1108. The fuel cell compartment 1108 is a portion of the internal volume of the container 1101, defined by one or more fuel cell partitions in the container. In this example, one or more fuel cell partitions include an inner wall partition 1107 that is generally parallel to and spaced apart from the side wall 1179 of the container 1101. Thus, the fuel cell compartment 1108 is a plenum defined between the inner wall partition 1107 and the side wall 1179 of the container 1101.

[0229] The battery 1103 (a battery array in this example) is located within the battery compartment 1178. The battery compartment 1178 is a portion of the internal volume of the container 1101, defined by one or more battery partitions. In this example, one or more battery partitions include a raised-floor battery partition 1176, which is generally parallel to and spaced apart from the bottom wall 1180 of the container 1101. Thus, the battery compartment 1178 is a plenum defined between the raised-floor battery partition 1176 and the bottom wall 1180 (floor) of the container 1101. (The raised-floor battery partition is also shown in Figure 1 by reference numeral 176.)

[0230] Figure 11 also shows an internal partition 1175 that partially defines the fuel cell compartment 1108 and also partially defines the battery compartment 1178. The internal partition 1175 is in the same plane as the raised-floor battery partition 1176. The raised-floor battery partition 1176 extends from the side wall of the container 1101 to the edge where it intersects with the internal wall partition 1107. The internal wall partition 1107 extends from the ceiling of the container 1101 to the edge where it intersects with the raised-floor battery partition 1176. The raised-floor battery partition 1176 is in a plane perpendicular to the internal wall partition 1107. The edge where the raised-floor battery partition 1176 and the internal wall partition 1107 intersect is on an axis spaced apart from the parallel outer walls of the container 1101. The internal partition 1175 extends from the edge where the raised floor battery partition 1176 and the inner wall partition 1107 intersect with the outer wall 1179 of the container 1101. In Figure 11, the internal partition 1175 has an internal vent to allow air to flow freely between the battery compartment 1178 and the fuel cell compartment 1108.

[0231] The control compartment is a portion of the internal volume of container 1101, separated from the fuel cell compartment 1108 by one or more fuel cell partitions 1107 and separated from the battery compartment 1178 by one or more fuel cell partitions 1176. The control compartment 1177 houses one or more of the following: UPS 1116, controller (which may be implemented as PLC 1112 and / or one or more relays 1167), one or more switches, galvanically isolated circuits (not shown in Figure 11 but extensively described above), inverters (not shown in Figure 11 but extensively described above), smoke detectors / alarms, heat detectors / alarms, gas detectors / alarms, oxygen monitoring systems, and any other features of other examples of power generation systems disclosed herein. For safety reasons, the control compartment 1177 may contain potential ignition sources that should be kept away from any potential hydrogen leaks.

[0232] The power generation system 1100 in Figure 11 includes a fan 1172 that reduces the air pressure in the fuel cell compartment 1108 so that air is drawn through the battery compartment 1178 and the fuel cell compartment 1108 and exits the container through an outlet vent. This is advantageous as it releases leaked hydrogen into the atmosphere through the outlet vent and also provides cooling to the batteries in the battery compartment 1178. The outlet vent is not visible in Figure 11, but Figure 1 shows how the fan 172 is adjacent to the outer wall of the container 101 (the rear wall in Figure 1). It will be understood that there is an opening (outlet vent) in the outer wall of the container 101 so that the fan 172 moves air from inside the fuel cell compartment 108 to outside the container 101 through the opening so that the air pressure inside the fuel cell compartment 108 is reduced to below the ambient air pressure. In the examples of Figures 1 and 11, the outflow vents are located on the outer walls of containers 101 and 1101, which also define the walls of fuel cell compartments 108 and 1108. In this way, fans 172 and 1172 can blow air out of containers 101 and 1101 through the outflow vents, thereby reducing the air pressure in the fuel cell compartments 108 and 1108 and the battery compartment 1178.

[0233] Returning to Figure 11, the power generation system 1100 in this example also includes an inlet vent 1174 on the outer wall of the container (on the left wall of container 1101 in Figure 11). A fan 1172 draws air from outside container 1101 into the battery compartment 1178 and the fuel cell compartment 1108 through the inlet vent 1174. In Figure 11, the inlet vent 1174 is located on the outer wall of container 1101, which also defines the battery compartment 1178. The inlet vent 1174 is located at the opposite end of container 1101 from the fuel cell compartment (and the internal vent in the internal partition 1175) so that the air drawn into the battery cell compartment 1178 through the inlet vent 1174 must travel the length of the battery compartment 1178 before it exits the battery compartment 1178 through the internal vent.

[0234] As schematically shown in Figure 11 by various airflow arrows, the raised-floor battery partition 1176 does not need to provide a strictly airtight barrier between the battery compartment 1187 and the control compartment 1177. Similarly, the inner-wall partition 1107 does not need to provide an airtight barrier between the fuel cell compartment 1108 and the control compartment 1177. The raised-floor battery partition 1176 should be sufficiently airtight so that the fan 1175 can maintain a sufficient air pressure difference between the battery compartment 1178 and the control compartment 1177, thereby allowing sufficient air to flow over the battery 1103 for cooling purposes. Similarly, the inner wall partition 1107 should be sufficiently airtight so that the fan 1175 can maintain a sufficient air pressure difference between the fuel cell compartment 1108 and the control compartment 1177, ensuring that hydrogen leaked from the fuel cell 1102 does not move into the control compartment 1177 and that there is sufficient airflow through the fuel cell compartment 1108 to quickly remove the leaked hydrogen.

[0235] In this example, the spill vent is located in the upper region of the outer wall defining the wall of the fuel cell compartment 1108, optionally near the ceiling of the container 1101, which helps remove the spilled hydrogen because the spilled hydrogen is less dense than air and therefore rises to the top of the fuel cell compartment 1108.

[0236] In this way, the fuel cell 1102 and battery 1103 are positioned in a negative pressure gas safety zone (negative to the ambient atmosphere and the control compartment 1177), and the airflow path is carefully managed through strategically placed and sized external outlet vents to ensure that any accidental hydrogen release from the fuel cell 1002 or battery 1003 is safely released into the atmosphere without encountering any ignition sources along the path of the airflow path. Any such potential ignition sources may be present in the control compartment 1177.

[0237] In this example, the fan 1172 can be implemented as a single ATEX fan for creating an air flow, which is continuously monitored (as described above with reference to the alarm trigger signal provided by the air flow sensor) to safely stop the fuel cell 1102 in case of power loss.

[0238] Another aspect of the power generation system 1100 illustrated in the figure relates to the positioning and operation of the hydrogen flow control valve 1166 (which may or may not be the same as the shut-off valve described above).

[0239] As described above, the fuel cell 1102 is located within the container 1101. Also, the hydrogen supply source 1106 is located outside the container 1101. The hydrogen flow control valve 1166 is also outside the container 1101 and in the conduit between the hydrogen supply source 1106 and the fuel cell 1102. In this example, the hydrogen flow control valve 1166 is located on a high-pressure hydrogen panel attached to the outer surface of the container 1101. The hydrogen flow control valve 1166 can be used to reduce the pressure of the high-pressure hydrogen from the hydrogen supply source 1106 before the high-pressure hydrogen is provided to the fuel cell 1102.

[0240] [[ID=...]] The power generation system 1100 also includes an inert gas control system 1181 configured to operate the hydrogen flow control valve 1166. The hydrogen flow control valve 1166 (or multiple valves if there are two or more) is triggered using an inert gas so that there is no ignition source within the high-pressure hydrogen panel.

[0241] In this way, the high-pressure hydrogen supply source is externally connected, and the hydrogen pressure drops before entering the container 1101, thus reducing the risk of an explosive atmosphere occurring within the container 1101.

[0242] The system in Figure 11 further includes a series of external solenoid valves (not shown) configured to operate the inert gas control system 1181 based on control signals received from a controller (such as PLC1112) or other safety / control system. This is advantageous as it allows for automated, electronically triggered gas shutoff without the risk of any ignition source in the vicinity of any hydrogen (particularly high-pressure hydrogen).

[0243] Fortunately, in this example, the hydrogen flow control valve 1166 is a normally closed valve. In this way, the valve is normally closed when de-energized so that the removal of all power in an emergency or failure situation eliminates any ignition source and gas supply.

[0244] Figure 12a shows a longitudinal section view of another example of the power generation system 1200. Figure 12b shows a side section view of the power generation system 1200 through the fuel cell compartment 1208. Features of Figures 12a and 12b described with reference to the previous drawings are given corresponding reference numbers in the 1200 series.

[0245] Similar to the example in Figure 11, the power generation system 1200 includes a container 1201, in this example a standard shipping container. The container 1201 has a footprint, the longitudinal aspect of which is indicated in Figure 12a by reference numeral 1283. The transverse aspect of the footprint is indicated in Figure 12b by reference numeral 1284. The power generation system 1200 includes a control compartment 1277, which is part of the internal volume of the container 1201.

[0246] The power generation system 1200 also includes a fuel cell compartment 1208 located within the footprint of container 1201. The fuel cell 1202 is located within the fuel cell compartment 1208. The fuel cell compartment 1208 is separated from the control compartment 1277 by one or more airtight fuel cell partitions 1207, and one or more airtight fuel cell partitions 1207 can be considered to define an airtight partition between the control compartment 1277 (which may potentially contain an ignition source as described above) and the fuel cell compartment 1208.

[0247] The power generation system 1200 further includes a battery compartment 1278, which is part of the internal volume of a container 1201 defined by one or more battery partitions 1276 (the batteries are located within the battery compartment 1278). One or more battery partitions 1276 may be the same as those described with reference to Figure 11.

[0248] In this example, the fan 1272 is configured to draw air from the battery compartment 1278 into the fuel cell compartment 1208. In this way, the fan 1272 can reduce the pressure in the battery compartment. Furthermore, in this example, the fuel cell compartment 1208 is open to the atmosphere. For example, as shown in Figure 12a, the outer wall of the container 1201 (the rightmost wall in Figure 12a) can include a sufficient number of louvers or vents so that there is no significant drop in air pressure across the entire outer wall. Thus, when the fan 1272 draws air into the fuel cell compartment 1208, the fuel cell compartment 1208 is immediately exposed to the atmosphere. In some examples, the outer wall of the container 1201, or a portion of the outer wall of the container 1201, can be completely removed so that the fuel cell compartment 1208 is fully open to the atmosphere.

[0249] In this way, the fan 1272 can provide airflow through the battery compartment 1278 to assist in cooling the battery, and can also facilitate airflow out of the fuel cell compartment 1208. As discussed above, this offers the advantage that in the unlikely event of a hydrogen leak in the fuel cell compartment 1208, hydrogen is released into the atmosphere without being exposed to any potential ignition sources in the control compartment 1277. The control compartment 1277 may include any of the components described above with reference to Figure 11.

[0250] In the example shown in Figure 12, the power generation system 1200 also includes an internal partition 1285 that partially defines a fuel cell compartment 1208 and also partially defines a battery compartment 1278. The fan 1272 is located in the internal partition 1285. In this implementation, the internal partition 1285 is in the same plane as one of the airtight fuel cell partitions 1207, but it will be understood that the power generation system 1200 may be configured differently while still achieving the desired airflow.

[0251] Regardless of the extent to which the fuel cell compartment 1208 is exposed to the atmosphere, there may be an outflow vent 1286 on the outer wall of the container 1207 that defines the fuel cell compartment 1208. In this example, the outflow vent 1286 extends around the corners of the two vertical walls of the container 1201, as shown in Figures 12a and 12b.

[0252] Advantageously, the spill vent 1286 is located in the uppermost region of the fuel cell compartment 1201. Since hydrogen is lighter than air, this helps to vent any hydrogen in the fuel cell compartment 1208. Furthermore, in this example, the power generation system 1200 further includes a cowl / ceiling 1282 within the fuel cell compartment 1208, which is angled such that it defines a surface that extends upward toward the spill vent 1286. The cowl / ceiling 1282 does not necessarily have to be planar, as shown in Figures 12a and 12b. For example, the cowl / ceiling 1282 can define a curve in either or both of the lateral and longitudinal dimensions, and this curve can be mathematically represented such that the curve has no turning points. That is, the cowl / ceiling 1282 can define a surface that extends upward toward the spill vent 1286 from any point on the surface. In this way, the cowl / ceiling 1282 does not have any recesses or pockets where hydrogen can accumulate instead of being released into the atmosphere.

[0253] The shape of the cowl / ceiling 1282 may be designed to create a passive vacuum that releases air from the fuel cell compartment 1208 into the atmosphere and draws air through the battery compartment 1278.

[0254] The power generation system further includes a hydrogen flow control valve 1266 located in the conduit between the hydrogen supply source 1206 and the fuel cell 1202. As described above, the hydrogen flow control valve 1266 is for reducing the pressure of hydrogen before it is supplied to the fuel cell 1202. Again, as described above, the hydrogen flow control valve 1266 is operated using the inert gas control system 1281. However, in this example, the hydrogen flow control valve 1266 is located within the footprint of the container 1201. It may be advantageous to have as many components as possible within the container in the sense that the container 1201 can be transported using existing methods, such as on the rear of a freight vehicle as a standard shipping container.

[0255] The power generation system 1201 may include an inflow vent within the outer wall of the container, as described above with reference to Figure 11.

[0256] In this example, one or more airtight fuel cell partitions 1207 include airtight inner wall partitions that are generally parallel to and spaced apart from the second side wall of the container, thereby defining a control compartment 1277 between the inner wall partition and the second side wall of the container.

[0257] In this way, the fuel cell compartment 1208 can be considered a gas-safe zone (e.g., an ATEX zone) isolated from the control compartment 1277 via an internal airtight partition that leaves the fuel cell 1202 open to the ambient air. Furthermore, as shown above, this allows the inert gas control system 1281 and the high-pressure valve 1266 to be brought inside the open vent footprint of the modified container 1201.

[0258] Returning to Figure 1, we will now describe how the burst panel 187 (which can also be described as an emergency vent release panel) can provide additional safety functionality to the power generation system 100.

[0259] As discussed above, the power generation system 100 includes a container having an internal volume (in this example, a transport container 101). The power generation system also includes a fuel cell compartment 108, which is a portion of the internal volume defined by one or more fuel cell partitions 107 in the container 101. The fuel cell 102 is located within the fuel cell compartment 108. A battery compartment 178 is also provided, which is a portion of the internal volume defined by one or more battery partitions 176. One or more batteries 103 are located within the battery compartment 178.

[0260] The power generation system 100 also includes a control compartment 177, which is part of an internal volume that is separated from the fuel cell compartment 108 by one or more fuel cell partitions 107 and separated from the battery compartment 178 by one or more battery partitions 176.

[0261] Furthermore, the power generation system includes one or more burst panels 187 on the outer wall or ceiling of the container 101. The burst panels 187 are configured to be removable from their respective frames on the outer wall or ceiling of the container 101 in response to a sudden increase in air pressure inside the container 101, for example, in the highly unlikely event of an explosion inside the container 101. In this way, the pressure inside the container 101 can be more moderately relieved. The burst panels 187 can be attached to their respective frames by perforated mounting areas designed to burst when a predetermined pressure inside the container 101 is exceeded.

[0262] In this example, multiple rupture panels 187 are located on the ceiling / roof of container 101, but in other examples, rupture panels may be located on the outer wall of container 101. In the unlikely event of a gas explosion, the resulting internal pressure is released through these sacrificial perforation rupture panels. These rupture panels 187 on the ceiling / roof release pressure in such a way that the walls of container 101 remain intact and damage to the surrounding area and / or personal injury to nearby operators is prevented.

[0263] In this example, there is at least one rupture panel located on the outer wall or ceiling of the container 101 that defines the fuel cell compartment 108. There is also at least one rupture panel located on the outer wall or ceiling of the container that defines the control compartment.

[0264] In some examples, the rupture panel 187 has one edge that is more firmly attached to the container 101 than the other edges of the rupture panel 187. For example, perforation areas along one of the edges of the rupture panel 187 may be designed so that these perforation areas rupture at a higher pressure than the other edges. In this way, when the pressure inside the container 101 increases sufficiently to blow off the rupture panel 187, the rupture panel 187 pivots around the more firmly attached edge and therefore does not completely separate from the container 101. This is another safety advantage because it reduces the possibility that the rupture panel 187 itself could cause damage to personnel or equipment in the vicinity of the power generation system 100.

[0265] heat exchanger Referring here to Figures 1 and 13, we will explain how a heat exchanger can advantageously utilize the heat extracted from a fuel cell during cooling for localized applications requiring heat. In the example of Figure 1, the heat exchanger is located within a fuel cell heat exchange cooling module 188 mounted on the exterior of container 101, in this example, on the roof of container 101. As shown in Figure 1, this fuel cell heat exchange cooling module 188 can provide a hot water source 1395. Advantageously, the fuel cell heat exchange cooling module 188 may be detachable from container 101 to facilitate the transport of container 101, particularly when container 101 is a standard-sized shipping container.

[0266] Figure 13 schematically shows an example of a fuel cell cooling circuit. The fuel cell system 1302 includes a fuel cell cooling loop 1388 for removing heat from the fuel cell 1302. The fuel cell can be air-cooled or liquid-cooled, and therefore the fuel cell cooling loop 1388 can transport either a gas or a liquid fluid for removing heat from the fuel cell.

[0267] Figure 13 also shows a heat exchanger 1389 for transferring heat from the fuel cell cooling loop 1388 so that it can be used to serve localized applications that require heat. Localized applications may include one or more of providing a hot water source, providing heating, and providing heating for one or more processes. The example illustrated in Figure 13 relates to providing a hot water source, but those skilled in the art will readily recognize that the heat extracted from the fuel cell cooling loop 1388 can be well utilized in many other ways.

[0268] In this example, Figure 13 includes an additional cooling loop 1390 for receiving heat from the fuel cell cooling loop 1388 via a heat exchanger 1389. Furthermore, the additional cooling loop 1390 can selectively heat water in a water tank 1394 so that it can be provided as a hot water source. In this example, the additional cooling loop 1390 has one or more valves that can be operated to selectively direct fluid into the additional cooling loop 1390 to heat the water in the water tank 1394. More specifically, there are two valves referred to as hot water tank circuit valves 1391 that, when opened, allow fluid in the additional cooling loop 1390 into the hot water tank circuit 1397. The hot water tank circuit 1397 includes another heat exchanger 1393 for heating water in the hot water tank 1394. When the hot water tank circuit valves 1391 are closed, the fluid does not move around the hot water tank circuit 1397. Thus, the hot water tank circuit valves 1391 can be operated to provide a hot water source on demand.

[0269] Figure 13 also shows a heat removal component 1396 that selectively transfers heat from the fluid in an additional cooling loop 1390 to the atmosphere. In this example, the heat removal component 1396 includes a radiator and a fan for dissipating unused heat. In some examples, the heat removal component 1396 activates automatically when the temperature of the fluid in the additional cooling loop 1390 exceeds a predetermined setpoint.

Claims

1. Power outlet and A fuel cell configured to selectively supply power to the aforementioned power outlet, A battery configured to selectively supply power to the aforementioned power outlet, An inverter for converting the DC voltage provided by the fuel cell into an AC voltage for supplying to the power outlet, A grid supply connector for receiving grid supply voltage and grid supply power, An uninterruptible power supply (UPS) having a grid input terminal, a power output terminal, and a battery connection terminal, The grid input terminal is connected to the grid supply connector, The power output terminal is connected to the power outlet, The battery connection terminal is connected to the battery, and the uninterruptible power supply (UPS) is connected to the battery. It is a controller, Receiving a grid supply characteristics signal that includes a grid supply power level representing the power level of the grid supply, Receiving a system load signal that represents the amount of power required by an external load connected to the aforementioned power outlet, The system receives one or more fuel cell parameters representing one or more operating parameters of the fuel cell, To provide a fuel cell power control signal such that power received from the grid supply is prioritized over power provided by the fuel cell, based on the system load signal, the grid supply characteristic signal, and one or more fuel cell parameters, wherein the fuel cell power control signal is for setting the control parameters of the fuel cell and / or for setting the control parameters of the inverter. Based on the aforementioned system load signal, the supply threshold is determined, The grid power supply level is compared with the supply threshold, If the grid power supply level is below the supply threshold, the fuel cell power control signal is set so that the fuel cell provides power to the power outlet. A controller is configured to set the fuel cell power control signal so that the fuel cell does not supply power to the power outlet if the grid power supply level is equal to or greater than the supply threshold, A power generation system equipped with the following features.

2. The aforementioned controller The system receives a battery charging signal that indicates the charge level of the aforementioned battery, The power generation system according to claim 1, further configured to provide the fuel cell power control signal based on the battery charging signal.

3. The aforementioned controller The process involves determining a fuel cell target value based on the system load signal and the battery charge signal, wherein the fuel cell target value represents the target level of the fuel cell. The power generation system according to claim 2, configured to set a fuel cell power control signal based on the fuel cell target value.

4. The power generation system according to claim 3, wherein the fuel cell is configured to supply power to the power outlet and to charge the battery.

5. The controller Receiving a grid supply signal representing the power level of the grid supply, The power generation system according to claim 3, further configured to determine the fuel cell target value based on the grid supply signal.

6. The aforementioned controller The fuel cell target current is determined based on the difference between the grid power supply level and the supply threshold, The power generation system according to claim 1, wherein if the grid power supply level is less than the supply threshold, the system is configured to set the fuel cell power control signal based on the fuel cell target current.

7. The power generation system according to any one of claims 1 to 6, wherein the fuel cell is configured to supply power to the power outlet.

8. The power generation system according to any one of claims 1 to 7, wherein the fuel cell is configured to provide power for charging the battery.

9. The power generation system according to claim 8, further comprising a DC-DC converter connected between the fuel cell and the battery.

10. It is a power generation system, Power outlet, A fuel cell configured to selectively supply power to the aforementioned power outlet, battery, Grid supply connector for receiving grid power, An uninterruptible power supply (UPS) having a grid input terminal, a power output terminal, and a battery connection terminal, The grid input terminal is connected to the grid supply connector, The power output terminal is connected to the power outlet, The battery connection terminal is connected to the battery, The UPS is configured to provide the power it receives at the grid input terminal and / or the battery connection terminal to the power output terminal. The UPS is configured to provide power received at the grid input terminal to the battery connection terminal in order to charge the battery, and the UPS comprises an uninterruptible power supply UPS. The fuel cell is configured to provide power for charging the battery, A power generation system in which the fuel cell is configured to supplement the grid-supplied power to charge the battery.

11. The power generation system according to claim 10, further comprising an inverter configured to convert a DC output voltage provided by the fuel cell into an inverter AC voltage, wherein the inverter is configured to provide the inverter AC voltage to the power outlet.

12. It is a power generation system, Power outlet and An inverter configured to convert a DC output voltage to an inverter AC voltage, wherein the inverter is configured to provide the inverter AC voltage to the power outlet, Batteries and A grid supply connector for receiving grid supply voltage, An uninterruptible power supply (UPS) having a grid input terminal, a power output terminal, and a battery connection terminal, The grid input terminal is connected to the grid supply connector, The power output terminal is connected to the power outlet, The battery connection terminal is connected to the battery, and the uninterruptible power supply (UPS) is connected to the battery. It is a controller, Receiving a grid supply characteristic signal that represents the characteristic level of the grid supply voltage, A controller is configured to provide an inverter control signal to the inverter based on the grid supply characteristic signal, wherein the inverter control signal is for setting or limiting the supplied inverter power output. The power generation system further comprises a recirculation switch configured to selectively connect the power output terminal of the UPS to the grid input terminal of the UPS.

13. Further comprising a fuel cell configured to provide a DC output voltage, The power generation system according to claim 12, wherein the inverter is configured to convert the DC output voltage provided by the fuel cell into the inverter AC voltage.

14. The power generation system according to claim 12 or 13, wherein the controller is configured to operate the recirculation switch based on the grid supply characteristic signal.

15. The power generation system according to any one of claims 12 to 14, wherein the controller is configured to operate the recirculation switch so that the recirculation switch connects the power output terminal to the grid input terminal of the UPS.

16. The power generation system according to any one of claims 12 to 15, further comprising a grid isolation switch configured to selectively disconnect the grid input terminal of the UPS from the grid supply connector.

17. The power generation system according to claim 16, wherein the controller is configured to operate the grid isolation switch based on the grid supply characteristic signal.

18. The power generation system according to claim 16, wherein the controller is configured to operate the grid isolation switch such that the grid isolation switch disconnects the grid input terminal of the UPS from the grid supply connector if the grid supply characteristic signal does not meet the grid supply quality threshold.

19. The power generation system according to any one of claims 16 to 18, wherein the controller is configured to set the grid disconnector switch to disconnect the grid input terminal of the UPS from the grid supply connector before the controller sets the recirculation switch to connect the recirculation switch to connect the power output terminal of the UPS to the grid input terminal of the UPS.

20. The aforementioned controller The power generation system according to claim 19, wherein a time delay is applied between setting the grid isolation switch to disconnect the grid input terminal of the UPS from the grid supply connector and setting the recirculation switch to connect the power output terminal of the UPS to the grid input terminal of the UPS.

21. The power generation system according to any one of claims 12 to 20, wherein the recirculation switch is configured to selectively connect the protective earthing terminal of the power output terminal to the neutral terminal and to one or more localized earthing rods of any choice.

22. The power generation system according to claim 21, wherein the protective earth terminal of the power output terminal is selectively connected to the protective earth terminal of the grid input terminal.

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