Abstract: An auxiliary circuit to inject fault current to a grid is provided. The circuit includes a pair of transformers including a first transformer and a second transformer, and a pair of SCRs including a first SCR and a second SCR. Each SCR remains in an OFF state and an ON state when AC voltage of the grid is in normal range and fault range, respectively. The circuit includes a capacitor electrically connected between the first transformer, the second transformer, and the first SCR. The circuit includes a diode biased by the second transformer and the capacitor to enable charging of the capacitor to a peak of AC voltage during one polarity of AC voltage when the AC voltage is in normal range. The capacitor discharges via the first SCR and the first transformer by injecting the fault current into the grid when the AC voltage is in the fault range.

Abstract: A power generation system includes a power source that is configured to communicate with at least one of a downstream load or a downstream device by changing a voltage on a power bus between the power source and the at least one of the downstream load or the downstream device, while power source provides power on the power bus to the at least one of the downstream load or the downstream device.

Abstract: A system for fuel cell based microgrid is provided. The system includes a plurality of fuel cell modules to generate DC power. The system includes a plurality of dual-mode inverters (DMIs) to convert the DC power into AC power. The system includes a plurality of DC switches to electrically connect or disconnect a fuel cell module from a DC bus. The DC bus is electrically coupled to the plurality of the DC switches. The plurality of DMIs includes a first set of DMIs, second set of DMIs, and a third set of DMIs. The first set is configured to electrically connect a first set of fuel cell modules with a grid. The second set of DMIs is configured to electrically connect a second set of fuel cell modules with a first load. The third set of DMIs is configured to electrically connect the DC bus with the first load.

Abstract: Embodiments of the present disclosure provide control systems and methods to reduce wastage of energy associated with fuel cell systems. The method includes transmitting DC power from a plurality of fuel cells of a set of power modules to a centralized DC bus through a first set of DC-DC converters. The method includes operating a second set of DC-DC converters to provide an output DC power by boosting a voltage level of the DC power from the centralized DC bus and further operating a first set of DC-AC inverters to convert the DC power from the second set of DC-DC converters to AC power. The method includes transmitting the AC power from the first set of DC-AC inverters to a grid. The AC power is transmitted to the grid at substantially unity power factor due to combined effect of switching modulation and MPPT of the first set of DC-AC inverters.

Abstract: Various embodiments may provide non-isolated single-input dual-output (SIDO) bi-directional buck-boost direct current (DC) to DC (DC-DC) converters. Various embodiments may provide a method for controlling a buck duty cycle of the non-isolated SIDO bi-directional buck-boost DC-DC converter such that a first voltage measured across a first portion of the non-isolated SIDO bi-directional buck-boost DC-DC converter is maintained at less than a voltage of a first load and a second voltage measured across a second portion of the non-isolated SIDO bi-directional buck-boost DC-DC converter is maintained at less than a voltage of a second load.

Abstract: A power generation system includes a power source that is configured to communicate with at least one of a downstream load or a downstream device by changing a voltage on a power bus between the power source and the at least one of the downstream load or the downstream device, while power source provides power on the power bus to the at least one of the downstream load or the downstream device.

Abstract: A fuel cell system column includes a first terminal plate connected to a first electrical output of the column, a second terminal plate connected to a second electrical output of the column, at least one first fuel cell stack located in a middle portion of the column between the first terminal plate and the second terminal plate, and at least one electrical connection which is electrically connected to the middle portion of the column and which is configured to provide a more uniform fuel utilization across the first column.

Abstract: Various embodiments may provide non-isolated single-input dual-output (SIDO) bi-directional buck-boost direct current (DC) to DC (DC-DC) converters. Various embodiments may provide a method for controlling a buck duty cycle of the non-isolated SIDO bi-directional buck-boost DC-DC converter such that a first voltage measured across a first portion of the non-isolated SIDO bi-directional buck-boost DC-DC converter is maintained at less than a voltage of a first load and a second voltage measured across a second portion of the non-isolated SIDO bi-directional buck-boost DC-DC converter is maintained at less than a voltage of a second load.

Abstract: A microgrid includes a power system configured to output system power and an automatic transfer switch (ATS). The ATS includes a normal terminal that is electrically connected to a grid power line configured to receive grid power from a power utility, an emergency terminal that is electrically connected to a system power line configured to receive system power from the power system, and a load terminal that is electrically connected to a critical load line configured to provide power to a critical load. The microgrid also includes a bypass line electrically connected to the system power line and the critical load line, so as to bypass the ATS, and a circuit breaker configured to control power flow through the bypass line.

Abstract: Systems, methods, and devices of the various embodiments provide a hardware and software architecture enabling electrochemical impedance spectroscopy (“EIS”) to be performed on multiple electrochemical devices, such as fuel cells, at the same time without human interaction with the electrochemical devices and to use EIS to dynamically monitor the performance of a fuel cell system. Embodiment methods may include determining an impedance of a set of fuel cells using electrochemical impedance spectroscopy, determining an ohmic polarization of the set of fuel cells from the impedance, determining a concentration polarization of the set of fuel cells from the impedance, comparing the ohmic polarization of the set of fuel cells to a first threshold, comparing the concentration polarization of the set of fuel cells to a second threshold, and initiating a corrective action when the ohmic polarization is above the first threshold or when the concentration polarization is below the second threshold.

Abstract: Systems, methods, and devices of the various embodiments provide a hardware and software architecture enabling electrochemical impedance spectroscopy (“EIS”) to be performed on multiple electrochemical devices, such as fuel cells, at the same time without human interaction with the electrochemical devices and to use EIS to dynamically monitor the performance of a fuel cell system. Embodiment methods may include determining an impedance of a set of fuel cells using electrochemical impedance spectroscopy, determining an ohmic polarization of the set of fuel cells from the impedance, determining a concentration polarization of the set of fuel cells from the impedance, comparing the ohmic polarization of the set of fuel cells to a first threshold, comparing the concentration polarization of the set of fuel cells to a second threshold, and initiating a corrective action when the ohmic polarization is above the first threshold or when the concentration polarization is below the second threshold.

Abstract: Various embodiments include methods and systems for implementing managing a microgrid system. The system may include a plurality of power module clusters, a plurality of uninterruptable power modules, a plurality of bidirectional direct current (DC)/DC converters, and a DC power bus. Each one of the power module clusters of the plurality of power module clusters may be electrically connected in parallel to an uninterruptable power module of the plurality of uninterruptable power modules and a first end of a bidirectional DC/DC converter of the plurality bidirectional DC/DC converters, and a second end of each one of the bidirectional DC/DC converters of the plurality of bidirectional DC/DC converters may be electrically connected to the DC power bus. In some embodiments, the plurality of bidirectional DC/DC converters may be electrically connected to in parallel by the DC power bus or in series via a DC power bus ring.

Abstract: A system and method of provided power to one or more electrical loads of an electrical load module is provided. The electrical load module includes an alternating current (AC) power input port, a direct current (DC) power input port, a power distribution device, a first power supply device, a second power supply device, and a first electrical load component. The power distribution device is electrically coupled to the AC power input port via a first connector and the DC power input port via a second connection. The first electrical load component is coupled to the first power supply device and the second power supply device. The first power supply device and the second power supply device are configured to provide power to the first electrical load component and a feed from an alternative power source system is directly connected to the DC power input port of the electrical load module.

Abstract: A fuel cell system column includes a first terminal plate connected to a first electrical output of the column, a second terminal plate connected to a second electrical output of the column, at least one first fuel cell stack located in a middle portion of the column between the first terminal plate and the second terminal plate, and at least one electrical connection which is electrically connected to the middle portion of the column and which is configured to provide a more uniform fuel utilization across the first column.

Abstract: Various embodiments include methods and systems for implementing managing a microgrid system. The system may include a plurality of power module clusters, a plurality of uninterruptable power modules, a plurality of bidirectional direct current (DC)/DC converters, and a DC power bus. Each one of the power module clusters of the plurality of power module clusters may be electrically connected in parallel to an uninterruptable power module of the plurality of uninterruptable power modules and a first end of a bidirectional DC/DC converter of the plurality bidirectional DC/DC converters, and a second end of each one of the bidirectional DC/DC converters of the plurality of bidirectional DC/DC converters may be electrically connected to the DC power bus. In some embodiments, the plurality of bidirectional DC/DC converters may be electrically connected to in parallel by the DC power bus or in series via a DC power bus ring.

Abstract: A method includes selecting a test waveform to inject from a first DC converter to at least one first DC power source other than a fuel cell, determining a first resulting ripple that will be generated in response to injecting the test waveform onto the battery, determining at least one offset waveform to inject from at least one second DC converter to at least one second DC power source to generate one or more second ripples which cancel the first resulting ripple, injecting the test waveform from the first DC converter to the at least one first DC power source, injecting the at least one offset waveform from the at least one second DC converter to the at least one second DC power source, and determining a characteristic of the first DC power source based at least in part on the impedance response of the first DC power source.

Abstract: Systems and methods are provided for creating and operating a Direct Current (DC) micro-grid. A DC micro-grid may include power generators, energy storage devices, and loads coupled to a common DC bus. Power electronics devices may couple the power generators, energy storage devices, and loads to the common DC bus and provide power transfer.

Abstract: A method includes selecting a test waveform to inject to a battery from a first DC converter, determining a first resulting ripple that will be generated in response to injecting the test waveform, determining at least one offset waveform to inject to at least one second DC power source from at least one second DC converter such that one or more second ripples will be provided that will cancel the first resulting ripple if the battery is charging, injecting the test waveform to the battery, injecting the at least one offset waveform to the at least one second DC power source, determining if the first resulting ripple has been cancelled, and determining if the battery is charging or discharging based on the step of determining if the first resulting ripple has been cancelled.

Abstract: A method of controlling an inverter having a three phase output and a plurality of single phase loads connected to respective one of the three phases of the three phase output includes determining if a first phase of the three phase output has a heavier load than a second phase of the three phase output, and providing a higher output power from the inverter to the first phase than to the second phase if it is determined that the first phase has a heavier load than the second phase.

Abstract: A method includes selecting a test waveform to inject to a battery from a first DC converter, determining a first resulting ripple that will be generated in response to injecting the test waveform, determining at least one offset waveform to inject to at least one second DC power source from at least one second DC converter such that one or more second ripples will be provided that will cancel the first resulting ripple if the battery is charging, injecting the test waveform to the battery, injecting the at least one offset waveform to the at least one second DC power source, determining if the first resulting ripple has been cancelled, and determining if the battery is charging or discharging based on the step of determining if the first resulting ripple has been cancelled.