Abstract: A wireless power transfer system is disclosed. The system includes a wireless power transmitter including a transmitter coil and a transmitter electric field shield disposed over the transmitter coil. The transmitter electric field shield includes a first printed circuit board (PCB) and a second PCB. Each of the first and second PCBs includes a number of apertures. The apertures of the first PCB do not overlap with the apertures of the second PCB. The system further includes a wireless power receiver including a receiver coil and a receiver electric field shield disposed over or underneath the receiver coil. The receiver electric field shield includes a PCB having a first layer and a second layer connected to one another. The first layer of the PCB mates with the receiver coil and the second layer of the PCB mates with an interface surface of the wireless power receiver.

Abstract: A power converter system is provided and includes a first switch circuit configured to receive a first Direct Current (DC) voltage, the first switch circuit coupled to a second switch circuit having a positive connection and a negative connection to receive a second DC voltage. The power converter system further includes a first capacitor, coupled between the positive connection and a neutral point, a second capacitor, coupled between the negative connection and the neutral point, and an Alternating Current (AC) switch circuit coupled to the first capacitor and to the second capacitor. The power converter system includes a controller configured to maintain a substantially equal voltage level across the first capacitor and the second capacitor, the controller being coupled to the first switch circuit, the second switch circuit, and the AC switch. A method of controlling the power converter system is further disclosed.

Abstract: A power converter system is provided and includes a first switch circuit configured to receive a first Direct Current (DC) voltage, the first switch circuit coupled to a second switch circuit having a positive connection and a negative connection to receive a second DC voltage. The power converter system further includes a first capacitor, coupled between the positive connection and a neutral point, a second capacitor, coupled between the negative connection and the neutral point, and an Alternating Current (AC) switch circuit coupled to the first capacitor and to the second capacitor. The power converter system includes a controller configured to maintain a substantially equal voltage level across the first capacitor and the second capacitor, the controller being coupled to the first switch circuit, the second switch circuit, and the AC switch. A method of controlling the power converter system is further disclosed.

Abstract: According to one aspect, embodiments of the invention provide a gate driver comprising a level shifter circuit configured to be coupled to a controller, to receive control signals from the controller, each control signal having a voltage with respect to a control ground, and to redefine the voltage of each control signal with respect to a chip ground to generate redefined control signals, a gate driver chip coupled to the level shifter circuit and configured to be coupled to at least one semiconductor device, the gate driver chip further configured to provide bipolar control signals to the at least one semiconductor device based on the redefined control signals, and at least one power source configured to provide at least one positive supply voltage to the gate driver chip and at least one negative supply voltage to the gate driver chip and to the chip ground.

Abstract: An uninterruptible power supply system (UPS) includes an interconnect circuit configured to receive three-phase AC input power from an AC power source and a plurality of UPS subsystems each coupled to the interconnect circuit. A first UPS subsystem includes first and second single-phase AC-to-DC converters. At least one second UPS subsystem includes third and fourth single-phase AC-to-DC converters. In a first mode of operation, the interconnect circuit is configured to conduct at least one phase of the AC input power to the first UPS subsystem and at least one phase of the AC input power to the second UPS subsystem, and, in a second mode of operation, to disconnect the AC input power from the first UPS subsystem and to conduct at least one phase of the AC input power to the second UPS subsystem.

Abstract: According to one aspect, embodiments of the invention provide a gate driver comprising a level shifter circuit configured to be coupled to a controller, to receive control signals from the controller, each control signal having a voltage with respect to a control ground, and to redefine the voltage of each control signal with respect to a chip ground to generate redefined control signals, a gate driver chip coupled to the level shifter circuit and configured to be coupled to at least one semiconductor device, the gate driver chip further configured to provide bipolar control signals to the at least one semiconductor device based on the redefined control signals, and at least one power source configured to provide at least one positive supply voltage to the gate driver chip and at least one negative supply voltage to the gate driver chip and to the chip ground.

Abstract: According to one aspect, embodiments of the invention provide a power system including an input configured to be coupled to a power source and to receive input power from the power source, an output configured to be coupled to a load and to provide output power to the load, a power converter coupled between the input and the output, and an active ripple filter coupled to one of the output and the input including a DC link having at least one DC link capacitor and configured to generate a cancelling ripple voltage to cancel a ripple current associated with the power converter.

Abstract: A power converter includes a battery having a positive terminal and a negative terminal, a first power input to receive AC input power, a second power input to receive DC input power from the battery, a first power output to charge the battery, a second power output to provide power to a load, a rectifier circuit coupled to the first power input, and a non-isolated single-stage power conversion circuit having an input and configured as a buck-boost converter. The power at the second power output is derived from the first power input and/or the second power input. The single-stage power conversion circuit is configured to convert an AC voltage to a DC voltage using a common energy storage element, and is coupled to the first power output and the rectifier circuit.

Abstract: An uninterruptible power supply system (UPS) includes an interconnect circuit configured to receive three-phase AC input power from an AC power source and a plurality of UPS subsystems each coupled to the interconnect circuit. A first UPS subsystem includes first and second single-phase AC-to-DC converters. At least one second UPS subsystem includes third and fourth single-phase AC-to-DC converters. In a first mode of operation, the interconnect circuit is configured to conduct at least one phase of the AC input power to the first UPS subsystem and at least one phase of the AC input power to the second UPS subsystem, and, in a second mode of operation, to disconnect the AC input power from the first UPS subsystem and to conduct at least one phase of the AC input power to the second UPS subsystem.

Abstract: At least one aspect of the invention is directed to an uninterruptible power supply.

Abstract: Disclosed are methods for charging batteries utilizing a charge balance approach, and charger systems using those methods. In one example, a method for charging a battery includes monitoring an amount of charge released by the battery while in a discharge state, recording the amount of charge released while in the discharge state, applying a voltage which results in current in reverse direction to the battery at a first voltage level for a time sufficient to introduce an amount of charge substantially equal to the recorded amount of charge released by the battery while in the discharge state, and maintaining the battery in a stand-by mode by applying a voltage which results in current in reverse direction to the battery at a second voltage level, the second voltage level being in a range sufficient to prevent self-discharge of the battery and insufficient to induce evaporation of electrolyte in the battery.

Abstract: A power converter includes a battery having a positive terminal and a negative terminal, a first power input to receive AC input power, a second power input to receive DC input power from the battery, a first power output to charge the battery, a second power output to provide power to a load, a rectifier circuit coupled to the first power input, and a non-isolated single-stage power conversion circuit having an input and configured as a buck-boost converter. The power at the second power output is derived from the first power input and/or the second power input. The single-stage power conversion circuit is configured to convert an AC voltage to a DC voltage using a common energy storage element, and is coupled to the first power output and the rectifier circuit.

Abstract: At least one aspect of the invention is directed to an uninterruptible power supply.

Abstract: Disclosed are methods for charging batteries utilizing a charge balance approach, and charger systems using those methods. In one example, a method for charging a battery includes monitoring an amount of charge released by the battery while in a discharge state, recording the amount of charge released while in the discharge state, applying a voltage which results in current in reverse direction to the battery at a first voltage level for a time sufficient to introduce an amount of charge substantially equal to the recorded amount of charge released by the battery while in the discharge state, and maintaining the battery in a stand-by mode by applying a voltage which results in current in reverse direction to the battery at a second voltage level, the second voltage level being in a range sufficient to prevent self-discharge of the battery and insufficient to induce evaporation of electrolyte in the battery.