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 isolated switching converter can include an inverting bridge, a transformer, a rectifying bridge, and control circuitry. The inverting bridge can receive an input voltage and deliver an output voltage to the transformer primary windings. The inverting bridge can include a plurality of half bridges cascaded across the input voltage. Each half bridge can include an input capacitor; upper and lower switches coupled across the input capacitor and connected at a switch node; and a DC blocking capacitor coupled between the switch node and a primary winding terminal. The rectifying bridge can have an input coupled to the secondary windings of the transformer and can deliver an output voltage of the isolated switching converter. The control circuitry can monitor inverter feedback signal(s) and generate phase staggered inverter drive signal(s). The control circuitry can also monitor rectifier feedback signal(s) and generate rectifier drive signals that operate the rectifying bridge.

Abstract: Systems and methods for current sensing are described. For example, a system may include a transformer including a winding that connects a first tap and a second tap; a circuit board; a first trace on a layer of the circuit board, wherein the first trace connects the first tap to a rectifier; a coil including one or more turns of trace on the layer of the circuit board, adjacent to the first trace; and a measurement circuit configured to estimate current flowing in the first trace based on voltage across the coil.

Abstract: A battery charging system can include a first charger module having a first AC side couplable to an AC source and a first DC side couplable to a battery and first control circuitry that operates the first charger to charge or discharge the battery; and a second charger module having a second AC side couplable to the AC source and a second DC side couplable to the battery and second control circuitry that operates the second charger to generate heat, wherein: if the first charger module is charging the battery from the AC source, the second control circuitry operates the second charger to generate heat without delivering charging current to the battery; and if the second charger is discharging the battery to the AC source, the second control circuitry operates the second charger to generate heat without delivering current to the AC source.

Abstract: Operating a battery charger having an AC side stacked half bridge configuration coupled to a primary winding of a transformer and a DC side stacked half bridge configuration coupled to a secondary winding of the transformer to provide heating can include either operating the AC side stacked half bridges to provide a current path through the primary winding that does not include an AC source or operating the DC side stacked half bridges to provide a current path through the secondary winding that does not include a battery. In the former case, operation can include operating the DC side stacked half bridges to alternate between switching states that selectively couple a battery to the secondary winding of the transformer. In the latter case, operation can include operating the AC side stacked half bridges to alternate between switching states that selectively couple the AC source to the primary winding.

Abstract: A battery charging system can include a stacked half bridge rectifier (“SHBR”) having an upper half bridge (“UHB”) and a lower half bridge (“LHB”); a blocking capacitor and a winding coupled between a midpoint of the UHB and a midpoint of the LHB; a battery coupled across the SHBR; and control circuitry that can selectively operate the SHBR as a switched capacitor converter (“SCC”) using the blocking capacitor as a flying capacitor by alternating between: a first switching state in which lower switches of the UHB and LHB are closed while upper switches of the UHB and LHB are opened; and a second switching state in which upper switches of the UHB and LHB are closed. The battery can further include first and second series-connected batteries having a midpoint coupled to a midpoint of the SHBR, and the SCC can operate as a balancer to equalize charge between the batteries.

Abstract: A battery charging system can include a stacked half bridge rectifier having an upper half bridge (“UHB”) and a lower half bridge (“LHB”); a blocking capacitor and a winding coupled between a midpoint of the UHB and a midpoint of the LHB; a battery coupled between an upper terminal of the UHB and a lower terminal of the LHB; and control circuitry that can selectively operate the stacked half bridge rectifier as a switched capacitor converter using the blocking capacitor as a flying capacitor by alternating between: a first switching state in which lower switches of the UHB and LHB are closed while upper switches of the UHB and LHB are opened; and a second switching state in which upper switches of the UHB and LHB are closed; wherein the switched capacitor converter operates as a booster to charge the battery from a DC voltage lower than the battery voltage.

Abstract: A power conversion system can include at least one stacked half bridge converter that further includes a first half bridge further comprising two switching devices in a half bridge configuration and a first capacitor coupled thereacross and a second half bridge further comprising two switching devices in a half bridge configuration and a second capacitor coupled thereacross. The at least one stacked half bridge converter can be disposed between an input of the power conversion system and an output of the power conversion system. The power conversion system can further include a transformer coupled to the at least one stacked half bridge converter by a blocking capacitor and control circuitry that operates the switching devices of the at least one stacked half bridge converter as a switched capacitor converter using the blocking capacitor as a flying capacitor to equalize charge between the first and second capacitors.

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: 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: 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: 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.