Abstract: A system includes a generator configured to be electrically coupled to a grid, an engine configured to drive the generator, and a solid state generator coupled between the grid and an energy storage device. The system further includes a bias controller configured to detect a frequency of the grid and to responsively provide a bias signal to a speed controller of the engine. The bias controller may include a frequency bias controller configured to generate a frequency bias load sharing signal responsive to the detected frequency of the grid and a load sharing controller that receives the frequency bias load sharing signal and that generates the bias signal responsive to the load sharing signal.

Abstract: A system includes a break-before-make automatic transfer switch (ATS) configured to selectively couple a utility grid and at least one distributed generator (e.g., a plurality of paralleled generators) to a load bus such that, in a state transition of the ATS, the utility grid and the at least one distributed generator are both disconnected from the load bus before the utility grid or the at least one distributed generator is connected to the load bus. The system further includes at least one converter configured to be coupled to the load bus and configured to provide power to the load bus during the state transition of the ATS.

Abstract: An uninterruptible power supply (UPS) system includes a first port configured to be coupled to an AC power source and a second port configured to be coupled to a load. The system also includes a UPS circuit including a first converter circuit coupled to the first port, a second converter circuit coupled to the second port and a DC bus coupling the first converter circuit to the second converter circuit and configured to be coupled to an auxiliary power source and a third converter circuit coupled to the second port and configured to receive power from a variably available power source. The system further includes a control circuit operatively associated with the UPS circuit and the third converter circuit and configured to cooperatively control the UPS circuit and the third converter circuit to selectively transfer power to the load from the AC power source and the variably available power source and from the variably available power source to the AC power source.

Abstract: A system includes a generator configured to be electrically coupled to a grid, an engine configured to drive the generator, and a solid state generator coupled between the grid and an energy storage device. The system further includes a bias controller configured to detect a frequency of the grid and to responsively provide a bias signal to a speed controller of the engine. The bias controller may include a frequency bias controller configured to generate a frequency bias load sharing signal responsive to the detected frequency of the grid and a load sharing controller that receives the frequency bias load sharing signal and that generates the bias signal responsive to the load sharing signal.

Abstract: An apparatus includes a rack including a plurality of vertically-stacked battery shelves and a vertically extending pipe disposed adjacent the rack. The apparatus further includes a plurality of ports fluidically coupled to the pipe and spaced apart along a length of the pipe, respective ones of the ports configured to direct an extinguishing agent from the pipe towards respective ones of the shelves.

Abstract: A system includes at least one generator coupled to an island grid, at least one energy storage unit and at least one converter coupled to the at least one energy storage unit and configured to be coupled to the island grid. The system further includes a control circuit configured to cause the at least one converter to transfer power between the at least one energy storage unit and the grid responsive to a change in a load on the island grid to maintain operation of the at least one generator at a predetermined operating point. The at least one generator may include a control system configured to match generator output to the load and the control circuit may be configured to maintain the control system of the at least one generator within a predetermined dynamic response capability limit responsive to the change in the load.

Abstract: A system includes a converter configured to be coupled between an energy storage unit and a grid and a control circuit configured to detect frequency and voltage variations of the grid and to responsively cause the converter to transfer power and reactive components to and/or from the grid. The control circuit may implement a power control loop having an inner frequency control loop and a reactive component control loop having an inner voltage control loop. The control circuit may provide feedforward from the inner frequency control loop to the inner voltage control loop to inhibit reactive component transfer in response to a voltage variation deviation of the grid due to a power transfer between the energy storage unit and the grid.

Abstract: An uninterruptible power supply (UPS) system includes a first port configured to be coupled to an AC power source and a second port configured to be coupled to a load. The system also includes a UPS circuit including a first converter circuit coupled to the first port, a second converter circuit coupled to the second port and a DC bus coupling the first converter circuit to the second converter circuit and configured to be coupled to an auxiliary power source and a third converter circuit coupled to the second port and configured to receive power from a variably available power source. The system further includes a control circuit operatively associated with the UPS circuit and the third converter circuit and configured to cooperatively control the UPS circuit and the third converter circuit to selectively transfer power to the load from the AC power source and the variably available power source and from the variably available power source to the AC power source.

Abstract: A system includes a switch configured to couple a generator to a utility grid, a first converter having a first port coupled to the generator, a second converter having a first port coupled to a second port of the first converter and a second port coupled to the utility grid, and a controller configured to control the switch and the first and second converters. The controller may be configured to cause the first and second converters to provide power to the utility grid from the generator after the generator starts and before a state of the generator meets a predetermined criterion.

Abstract: A system includes at least one variable speed generator system configured to provide power to a load bus and at least one fixed speed generator configured to provide power to the load bus. The system also includes a solid state generator (SSG) system including at least one energy storage device and a converter coupled to the at least one energy storage device and configured to transfer power between the at least one energy storage device and the load bus. The system further includes a control system configured to control the at least one variable speed generator system, the at least one fixed speed generator and the SSG system responsive to changes in a load on the load bus.

Abstract: An uninterruptible power supply (UPS) system includes a first port configured to be coupled to an AC power source and a second port configured to be coupled to a load. The system also includes a UPS circuit including a first converter circuit coupled to the first port, a second converter circuit coupled to the second port and a DC bus coupling the first converter circuit to the second converter circuit and configured to be coupled to an auxiliary power source and a third converter circuit coupled to the second port and configured to receive power from a variably available power source. The system further includes a control circuit operatively associated with the UPS circuit and the third converter circuit and configured to cooperatively control the UPS circuit and the third converter circuit to selectively transfer power to the load from the AC power source and the variably available power source and from the variably available power source to the AC power source.

Abstract: A system includes a converter configured to be coupled between an energy storage unit and a grid and a control circuit configured to detect frequency and voltage variations of the grid and to responsively cause the converter to transfer power and reactive components to and/or from the grid. The control circuit may implement a power control loop having an inner frequency control loop and a reactive component control loop having an inner voltage control loop. The control circuit may provide feedforward from the inner frequency control loop to the inner voltage control loop to inhibit reactive component transfer in response to a voltage variation deviation of the grid due to a power transfer between the energy storage unit and the grid.

Abstract: An uninterruptible power supply (UPS) system includes a first port configured to be coupled to an AC power source and a second port configured to be coupled to a load. The system also includes a UPS circuit including a first converter circuit coupled to the first port, a second converter circuit coupled to the second port and a DC bus coupling the first converter circuit to the second converter circuit and configured to be coupled to an auxiliary power source and a third converter circuit coupled to the second port and configured to receive power from a variably available power source. The system further includes a control circuit operatively associated with the UPS circuit and the third converter circuit and configured to cooperatively control the UPS circuit and the third converter circuit to selectively transfer power to the load from the AC power source and the variably available power source and from the variably available power source to the AC power source.

Abstract: A system includes a first DC rail configured to be coupled to a first terminal of a first energy storage device (e.g., a battery), a second DC rail configured to be coupled to a first terminal of a second energy storage device (e.g., an ultracapacitor), and a plurality of converter legs coupled between the first and second DC rails and including at least one first converter leg configured to be coupled to a second terminal of the first energy storage device and at least one second converter leg configured to be coupled to second terminal of the second energy storage device. The system further includes a switch configured to couple and decouple the second terminals of the first and second energy storage devices. The at least one first converter leg and the at least one second converter leg provide different current capacities to deal with differences in power density of the energy storage devices.

Abstract: A system includes at least one generator coupled to an island grid, at least one energy storage unit and at least one converter coupled to the at least one energy storage unit and configured to be coupled to the island grid. The system further includes a control circuit configured to cause the at least one converter to transfer power between the at least one energy storage unit and the grid responsive to a change in a load on the island grid to maintain operation of the at least one generator at a predetermined operating point. The at least one generator may include a control system configured to match generator output to the load and the control circuit may be configured to maintain the control system of the at least one generator within a predetermined dynamic response capability limit responsive to the change in the load.

Abstract: A system includes at least one generator coupled to an island grid, at least one energy storage unit and at least one converter coupled to the at least one energy storage unit and configured to be coupled to the island grid. The system further includes a control circuit configured to cause the at least one converter to transfer power between the at least one energy storage unit and the grid responsive to a change in a load on the island grid to maintain operation of the at least one generator at a predetermined operating point. The at least one generator may include a control system configured to match generator output to the load and the control circuit may be configured to maintain the control system of the at least one generator within a predetermined dynamic response capability limit responsive to the change in the load.

Abstract: Some embodiments of the inventive subject matter provide methods of operating an uninterruptible power supply (UPS) configured to provide power to a load from first and second power sources, e.g., from a utility source and a battery or other backup source. The methods include operating the UPS to momentarily provide an altered voltage waveform in coordination with a transition of the load between first and second power sources. For example, the altered voltage waveform may provide a momentarily increased voltage rate of change to compensate for a transient current demand presented by the load.

Abstract: High voltage direct current systems are provided including one or more outlets and an electronic current limiter circuit associated with the one or more outlets. The electronic current limiter circuit is configured to limit current inrush when a connector is plugged into and/or unplugged from the one or more outlets when a direct current bus associated with the one or more outlets is energized so as not to damage the connector; and/or isolate direct current faults and/or excess current draw in a load connected to the one or more outlets so as to protect the system from shutdown.

Abstract: A system includes at least one variable speed generator system configured to provide power to a load bus and at least one fixed speed generator configured to provide power to the load bus. The system also includes a solid state generator (SSG) system including at least one energy storage device and a converter coupled to the at least one energy storage device and configured to transfer power between the at least one energy storage device and the load bus. The system further includes a control system configured to control the at least one variable speed generator system, the at least one fixed speed generator and the SSG system responsive to changes in a load on the load bus.

Abstract: A system includes a first DC rail configured to be coupled to a first terminal of a first energy storage device (e.g., a battery), a second DC rail configured to be coupled to a first terminal of a second energy storage device (e.g., an ultracapacitor), and a plurality of converter legs coupled between the first and second DC rails and including at least one first converter leg configured to be coupled to a second terminal of the first energy storage device and at least one second converter leg configured to be coupled to second terminal of the second energy storage device. The system further includes a switch configured to couple and decouple the second terminals of the first and second energy storage devices. The at least one first converter leg and the at least one second converter leg provide different current capacities to deal with differences in power density of the energy storage devices.