Abstract: Current pulsing improves the performance of fuel cells in a fuel cell stack based power system. Voltage clamping limits the voltage peaks that occur after a current pulse. In a hybrid power system, an electric storage device supplies the loads during current pulsing. The electric storage device may sink current to achieve the voltage clamping, and/or power system may employ other the voltage clamping circuits.

Abstract: Current pulsing improves the performance of fuel cells in a fuel cell stack based power system. Voltage clamping limits the voltage peaks that occur after a current pulse. In a hybrid power system, an electric storage device supplies the loads during current pulsing. The electric storage device may sink current to achieve the voltage clamping, and/or power system may employ other the voltage clamping circuits.

Abstract: A hybrid power module suitable for use in an array of hybrid power modules comprises a fuel cell stack, an energy storage device, charger circuit operable to charge the energy storage device from the fuel cell stack and/or an external power source at approximately a defined voltage; a stack disconnect switch operable to provide and remove an electrical path between the fuel cell stack and a terminal of the power module, and a unidirectional current flow device electrically coupled to provide a unidirectional current path from the charger circuit to the terminal of the power module when forward biased.

Abstract: An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Abstract: An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Abstract: A fuel cell system determines each of a battery charging current error, a battery voltage error, and a stack current error. The fuel cell system regulates current through a series pass element in response to a greater of the determined errors. Thus, the fuel cell system operates in three modes: battery voltage limiting mode, stack current limiting mode and battery charging current limiting mode. Additionally, there can be a fourth “saturation” mode where the stack voltage VS drops below the battery voltage VB as the load pulls even more current. Individual fuel cell systems can be combined in series and/or parallel to produce a combined fuel cell system having a desired output voltage and current.

Abstract: An electric power plant includes an array of fuel cell systems. The fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage.

Abstract: A black start operation employs the accumulation of power resulting from a reaction of fuel and ambient oxidant passively seeped or diffused into a fuel cell stack to bootstrap the fuel cell system operation.

Abstract: A fuel cell system electrically couples a battery in parallel with the fuel cell stack to power a load. An operational condition of the battery is compared to a desired operating condition and a partial pressure of a reactant flow to at least a portion of the fuel cell stack is adjusted based on the determined amount of deviation. The operational condition can include voltage, charge of the battery. Individual fuel cell systems can be combined in series and/or parallel to produce a combined fuel cell system having a desired output voltage and current.

Abstract: An ultracapacitor based power storage device suitable for use in hybrid fuel cell systems and other power systems includes circuitry for simulating the response of a battery. A voltage current limiting circuit may be employed with a variety of electrical storage devices, for example, ultracapacitors and batteries.

Abstract: An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Abstract: An ultracapacitor based power storage device suitable for use in hybrid fuel cell systems and other power systems includes circuitry for simulating the response of a battery. A voltage current limiting circuit may be employed with a variety of electrical storage devices, for example, ultracapacitors and batteries.

Abstract: Current pulsing improves the performance of fuel cells in a fuel cell stack based power system. Voltage clamping limits the voltage peaks that occur after a current pulse. In a hybrid power system, an electric storage device supplies the loads during current pulsing. The electric storage device may sink current to achieve the voltage clamping, and/or power system may employ other the voltage clamping circuits.

Abstract: A black start operation employs the accumulation of power resulting from a reaction of fuel and ambient oxidant passively seeped or diffused into a fuel cell stack to bootstrap the fuel cell system operation.

Abstract: An electric power plant includes an array of fuel cell systems. The fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage.

Abstract: Regenerative fuel cell electric power plants and operating methods therefor are provided. An embodiment of the present power plant comprises a regenerative fuel cell stack, supply systems for supplying an oxidant gas to the oxidant inlet and a fuel gas to the fuel inlet, respectively, of the stack when operating in power generation mode, a power supply system for connecting a power source to the stack for operation in electrolysis mode, a system for supplying a humidified carrier gas to the stack when operating in electrolysis mode; and, a storage system for storing hydrogen generated during electrolysis.

Abstract: In one embodiment, an electric power plant comprises an array of fuel cell systems, the fuel cell systems each comprising a regenerative fuel cell stack, an oxidant supply system for supplying an oxidant gas to the stacks, a fuel supply system for supplying a fuel gas to the stacks, a system for supplying a humidified carrier gas to the stacks, a DC current supply system for connecting a power source across the stacks, and a storage system for storing hydrogen received from the stacks. In power generation mode, the fuel cells of the present power plant generate electricity for supply to one or more electrical loads. In electrolysis mode, the stacks generate hydrogen from a humidified carrier gas stream.

Abstract: An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Abstract: A fuel cell system determines each of a battery charging current error, a battery voltage error, and a stack current error. The fuel cell system regulates current through a series pass element in response to a greater of the determined errors. Thus, the fuel cell system operates in three modes: battery voltage limiting mode, stack current limiting mode and battery charging current limiting mode. Additionally, there can be a fourth “saturation” mode where the stack voltage VS drops below the battery voltage VB as the load pulls even more current. Individual fuel cell systems can be combined in series and/or parallel to produce a combined fuel cell system having a desired output voltage and current.

Abstract: A fuel cell system determines each of a battery charging current error, a battery voltage error, and a stack current error. The fuel cell system regulates current through a series pass element in response to a greater of the determined errors, operating in three modes: battery voltage limiting mode, stack current limiting mode and battery charging current limiting mode. Additionally, there can be a fourth “saturation” mode where the stack voltage VS drops below the battery voltage VB. A voltage difference across the series pass element is compared to a desired condition such as a saturation level, and a partial pressure of a reactant flow to the fuel cell stack adjusted based on the determined amount of deviation limiting the energy dissipated by the series pass element. Individual fuel cell systems can be combined in series and/or parallel to produce a combined fuel cell system having a desired output voltage and current.