Abstract: An electrical system can include an isolated bidirectional converter (having an input couplable to a grid connection and an output couplable to a battery) and an isolated converter (having an input coupled to the input of the isolated bidirectional converter and couplable to the grid connection, with an AC output coupled to a convenience outlet). The electrical system can further include a controller that controls operation of the converters to operate in one of a plurality of modes including a charging mode in which the isolated bidirectional converter operates in a forward direction to charge the battery and the non-isolated converter powers the convenience outlet from the grid connection, and a non-charging mode in which the isolated bidirectional converter operates in a reverse direction to power the non-isolated converter from the battery and the non-isolated converter powers the convenience outlet.

Abstract: An energy storage system can include a battery, a power converter comprising a first plurality of switching devices coupled to the battery and a second plurality of switching devices coupled between the first plurality of switching devices and an AC power system, and control circuitry that determines whether the AC power system is a single/split phase system or a three phase system and operates the first and second pluralities of switching devices accordingly. The control circuitry can include a microcontroller and a plurality of voltage sensors each configured to monitor a magnitude and a phase of a voltage to allow the control circuitry to determine whether the AC power system is a single/split phase system or a three phase system and whether the AC power system is connected with a line to line or line to neutral fault condition.

Abstract: An AC-AC converter can include a stack of four switches. An input of the converter can be coupled across the stack of four switches, and an output of the converter can be taken from first terminal coupled to a connection point of first and second switches of the stack and a second terminal coupled to a connection point of third and fourth switches of the stack. The converter can further include a controller that operates the switches such that during a positive half cycle of an AC input voltage, the first and second switches are operated with an alternating 50% duty cycle and the third and fourth switches are constantly on, and during the negative half cycle of the AC input voltage, the third and fourth switches are operated with an alternating 50% duty cycle and the first and second switches are constantly on.

Abstract: Systems and methods for power conversion are described. Symmetric topologies and modulation schemes are described that may reduce common-mode noise. For example, a system may include a transformer including a first secondary winding and a second secondary winding; a rectifier, including a set of switches, that connects taps of the first secondary winding and the second secondary winding to a first terminal and a second terminal, wherein the rectifier is symmetric with respect to the first secondary winding and the second secondary winding; a battery connected between the first terminal and the second terminal; and a processing apparatus that is configured to control the set of switches to rectify a multilevel voltage signal on the transformer, including: selecting a modulation scheme from among two or more modulation schemes based on a measured voltage level of the battery.

Abstract: An electrical system can include an isolated bidirectional converter (having an input couplable to a grid connection and an output couplable to a battery) and an isolated converter (having an input coupled to the input of the isolated bidirectional converter and couplable to the grid connection, with an AC output coupled to a convenience outlet). The electrical system can further include a controller that controls operation of the converters to operate in one of a plurality of modes including a charging mode in which the isolated bidirectional converter operates in a forward direction to charge the battery and the non-isolated converter powers the convenience outlet from the grid connection, and a non-charging mode in which the isolated bidirectional converter operates in a reverse direction to power the non-isolated converter from the battery and the non-isolated converter powers the convenience outlet.

Abstract: Integrated power modules according to the present technology may include a printed circuit board characterized by a first surface and a second surface. The integrated power modules may include one or more surface-mounted components coupled with the first surface of the printed circuit board. The integrated power modules may include a heat-transfer substrate. The integrated power modules may include one or more gallium nitride transistors coupled between and soldered to each of the second surface of the printed circuit board and the heat-transfer substrate. The integrated power modules may include one or more spacers coupled between and soldered to each of the printed circuit board and the heat-transfer substrate.

Abstract: A stacked half bridge converter may be configured to provide an AC output voltage from either a DC or an AC input voltage. The switching devices of the converter may be operated according to a plurality of switching sequences, each switching sequence including one or more switching patterns, each switching pattern including one or more switching states of the switching devices. The switching sequences, patterns, and states may be selected to improve operation of the converter, by regulating the voltage at a neutral point of the converter to reduce ripple, increase switching efficiency, protect the switching devices from overvoltages, and the like.

Abstract: A charger for a battery power system can include first and second switching bridges with inputs couplable to an AC source, at least one transformer having two or more primary windings (connected in series and coupled to the switching bridges) and at least two secondary windings, and second rectifier/chargers, each coupled to at least one of the secondary windings and couplable to at least one battery. The switching bridges may be respectively operable during positive and negative half cycles of the AC source to deliver an AC voltage to the transformer. The rectifier/chargers may be operable in a first mode to receive an AC voltage from the transformer and deliver a DC voltage for charging the respective battery. In some multi-battery embodiments, the rectifier/chargers may also be operable in a second mode to deliver an AC voltage from a respective battery to the transformer to balance charge between the batteries.

Abstract: Systems and methods for power conversion are described. For example, a system may include a transformer including a plurality of secondary windings; a first set of switches connecting respective taps of the plurality of secondary windings to a first terminal; a second set of switches connecting the respective taps of the plurality of secondary windings to a second terminal; and an electrical load connected between the first terminal and the second terminal.

Abstract: Systems and methods for power conversion are described. For example, a system may include a transformer including a plurality of secondary windings; a first set of switches connecting respective taps of the plurality of secondary windings to a first terminal; a second set of switches connecting the respective taps of the plurality of secondary windings to a second terminal; and an electrical load connected between the first terminal and the second terminal.

Abstract: An electrical system can include a first bidirectional AC-DC converter having an input couplable to a grid connection and an output couplable to a battery and a second bidirectional AC-DC converter having an input couplable to the grid connection or a convenience outlet and an output couplable to the battery. The electrical system can further include a controller that controls the first and second converters to operate in a plurality of modes including a two-stage charging mode in which the first and second converters operate in a forward direction to charge the battery, a single-stage charging mode in which the first converter operates in a forward direction to charge the battery and the second converter operates in a reverse direction to power the convenience outlet, and a non-charging mode in which the first converter is idle and the second converter operates in a reverse direction to power the convenience outlet.

Abstract: An AC-AC converter can include a stack of four switches. An input of the converter can be coupled across the stack of four switches, and an output of the converter can be taken from first terminal coupled to a connection point of first and second switches of the stack and a second terminal coupled to a connection point of third and fourth switches of the stack. The converter can further include a controller that operates the switches such that during a positive half cycle of an AC input voltage, the first and second switches are operated with an alternating 50% duty cycle and the third and fourth switches are constantly on, and during the negative half cycle of the AC input voltage, the third and fourth switches are operated with an alternating 50% duty cycle and the first and second switches are constantly on.

Abstract: An electrical system can include an isolated bidirectional converter (having an input couplable to a grid connection and an output couplable to a battery) and an isolated converter (having an input coupled to the input of the isolated bidirectional converter and couplable to the grid connection, with an AC output coupled to a convenience outlet). The electrical system can further include a controller that controls operation of the converters to operate in one of a plurality of modes including a charging mode in which the isolated bidirectional converter operates in a forward direction to charge the battery and the non-isolated converter powers the convenience outlet from the grid connection, and a non-charging mode in which the isolated bidirectional converter operates in a reverse direction to power the non-isolated converter from the battery and the non-isolated converter powers the convenience outlet.

Abstract: Integrated power modules according to the present technology may include a printed circuit board characterized by a first surface and a second surface. The integrated power modules may include one or more surface-mounted components coupled with the first surface of the printed circuit board. The integrated power modules may include a heat-transfer substrate. The integrated power modules may include one or more gallium nitride transistors coupled between and soldered to each of the second surface of the printed circuit board and the heat-transfer substrate. The integrated power modules may include one or more spacers coupled between and soldered to each of the printed circuit board and the heat-transfer substrate.

Abstract: An energy storage system can include a battery, a power converter comprising a first plurality of switching devices coupled to the battery and a second plurality of switching devices coupled between the first plurality of switching devices and an AC power system, and control circuitry that determines whether the AC power system is a single/split phase system or a three phase system and operates the first and second pluralities of switching devices accordingly.

Abstract: Systems and methods for power conversion are described. Symmetric topologies and modulation schemes are described that may reduce common-mode noise. For example, a system may include a transformer including a first secondary winding and a second secondary winding; a rectifier, including a set of switches, that connects taps of the first secondary winding and the second secondary winding to a first terminal and a second terminal, wherein the rectifier is symmetric with respect to the first secondary winding and the second secondary winding; a battery connected between the first terminal and the second terminal; and a processing apparatus that is configured to control the set of switches to rectify a multilevel voltage signal on the transformer, including: selecting a modulation scheme from among two or more modulation schemes based on a measured voltage level of the battery.

Abstract: A switching system can include a main switching device configured to switch a voltage, a gate driver having an output coupled to a drive terminal of the main switching device and configured to deliver a drive signal to the main switching device, and a clamp circuit. The clamp circuit can be coupled to the drive terminal of the main switching device. The clamp circuit can include a logic gate configured to drive a clamp switching device coupled to and configured to clamp a voltage at the drive terminal of the main switching device. A drive signal of the clamp switching device can be substantially complementary to the main switching device drive signal. The logic gate can provide at least a portion of a delay between switching transitions of the main switching device and switching transitions of the clamp switching device.

Abstract: Aspects of the present disclosure involve a system and method for providing a boosted voltage using a single stage dual active bridge converter. In one embodiment, the single stage dual active bridge converter is introduced for high voltage charging using phase shift and frequency control. Phase shift and frequency control can be implemented on duty cycled switches and pulse width modulated switches in order to achieve a desired output voltage. In another embodiment, the phase shift and frequency controlled single stage dual active bridge converter is replicated in modular form to provide a single-phase system that provides a voltage for charging a high voltage system. In yet another embodiment, the phase shift and frequency controlled single stage dual active bridge converter is replicated in modular form to provide a three-phase system that provides a voltage for charging a high voltage system.

Abstract: A stacked half bridge converter may be configured to provide an AC output voltage from either a DC or an AC input voltage. The switching devices of the converter may be operated according to a plurality of switching sequences, each switching sequence including one or more switching patterns, each switching pattern including one or more switching states of the switching devices. The switching sequences, patterns, and states may be selected to improve operation of the converter, by regulating the voltage at a neutral point of the converter to reduce ripple, increase switching efficiency, protect the switching devices from overvoltages, and the like.

Abstract: A high voltage battery system can receive power from an AC grid and deliver power to a low voltage battery system. Embodiments can include an active filter and high voltage to low voltage (HVLV) DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system and further to stabilize the voltage presented to the HVLV DCDC converter to improve its operating efficiency.