A soft switching resonant converter is disclosed. The converter includes a power switch operable to connect and disconnect a DC link rail node and an output node. A resonant capacitor is coupled with the power switch. An auxiliary leg is coupled with a DC link midpoint node and the output node. An active damper is coupled in series with the resonant capacitor and the output node and is controllable to provide a first resistance of the active damper in a first state and a second resistance of the active damper in a second state, the first resistance having a lower magnitude than the second resistance. A driver controls the damper switch to provide a first resistance during the soft switching operation of the power switch and a second resistance after the soft switching operation of the power switch.

A high-frequency power supply device is provided with an AC-DC converter for converting an input from a three-phase alternating-current source into a direct current and a high-frequency amplifier including multiple FET elements and outputting a high-frequency alternating-current power, with the output of the AC-DC converter being directly input to the high-frequency amplifier, and further includes a phase conversion circuit for imparting phase differences to gate signals to be input to the multiple FET elements so as to offset fluctuation components included in the direct current. The device generates the high-frequency alternating-current power by converting the input from the three-phase alternating-current source into the direct current, directly inputting the direct current to the high-frequency amplifier, imparting the phase differences to the gate signals to be input to the multiple FET elements so as to offset the fluctuation components included in the direct current, and performing switching.

Inverter systems, circuits and associated control techniques for providing efficient delivery of high-frequency (HF) power and radio-frequency (RF) power into variable load impedances while maintaining resistive/inductive loading of the constituent inverters for zero voltage switching (ZVS) are described. The inverter architecture and associated control techniques for providing efficient delivery of HF into variable load impedances includes a first inverter having an output coupled to an input of an immittance converter. An output of the immittance converter is coupled to a second inverter. The second inverter maybe either serially or parallel coupled between the output of the immittance converter and a load.

Unique systems, methods, techniques and apparatuses of a power converter are disclosed. One exemplary embodiment is an electrical power conversion system comprising a first converter stage, a second converter stage, a third converter stage, and a control system. The first converter stage is operable to boost DC power received from a DC power source. The second converter stage is operable to boost DC power received from the first converter stage. The third converter stage includes an inverter. The control system is structured to receive as input voltage (V.sub.pv) and current (I.sub.pv) output by the DC power source, voltage (V.sub.dc) output by the second controller stage, and voltage (V.sub.ac) and a current (I.sub.ac) which are output by the third stage to an AC electrical power system, provide a control command for the first converter stage, and process the information of V.sub.dc, V.sub.ac and I.sub.ac to provide control commands for the inverter switches.

The resonant inverter circuit includes two or more switch elements. A detector detects an output current of the switch elements. A resonance frequency determiner determines that the resonance frequency of the resonant inverter circuit is abnormal when a number of times an absolute value of a current detected by the detector at turn-off of the switch elements is equal to or greater than a threshold is equal to or greater than a predetermined number of times that is two or more during a predetermined period that is equal to or longer than two switching periods of the switch elements. A controller causes the resonant inverter circuit to stop a switching operation when the resonance frequency determiner determines that the resonance frequency of the resonant inverter circuit is abnormal.

A power converter and a method of operation thereof is disclosed including an input, an output, a sensor unit, a switched power converter, and a processor module. The power converter may convert an input power into an output power. The power converter may sense real-time measurements of the input power and the output power to determine a real-time calculated efficiency. The power converter may chop the input power into sized and positioned portions of the input power based on a plurality of determined operating parameters. The power converter may determine the operating parameters based on the real-time calculated efficiency and on a plurality of other operating factors/conditions.

A high efficiency multi-mode/multi-phase power conversion device has DC-boost receiving input power from a plurality of DC (e.g., solar) sources, power inverters and an AC grid supply. Power conversion switches are arranged in a stacked configuration with controllable inner and outer switches conveying: in an non-inverting switched mode, an AC voltage from power from the AC grid supply; in an inverting outer switched mode, an AC voltage from power from the AC grid supply; and in an inverting outer and inner switched mode, an inverted voltage from power from the DC-boost circuit. At least one input switch and output to the AC grid supply is coupled to an output of the power inverters and a resonant circuit is coupled to the input switch. A rectifier and/or high voltage AC output tap is coupled to the resonant circuit and a controller is coupled to the power conversion switches and the input switch.

A multilevel stage of a bidirectional AC power converter, comprising: a set of switches in series, a set of capacitors in series, the set of capacitors being in parallel with the set of switches; a number of sets of diodes in series; a center tap along the set of switches in series; and a pair of taps, respectively after the first and before the last switch of the set of switches in series; wherein each node between respective capacitors is connected to a node between respective diodes. A converter first stage for a 3-level converter has 6 switches, two capacitors, and two diodes, with the junction between diodes connected to the junction between capacitors, and the diode legs between switches 2-3 and 4-5. The center tap is between switches 3-4, and the pair of taps between switches 1-2 and 5-6.

An AC/DC Switching Mode Power Supply (SMPS) comprises a PFC stage, an isolated LLC DC/DC converter stage, and a control circuit that provides feedback/control signals to PFC and LLC controllers, to enable a plurality of operating modes, dependent on a sensed peak AC input voltage and required output voltage Vo. The PFC provides a first DC bus voltage Vdc (e.g. 200V) for low line AC input and a second DC bus voltage (e.g. 400V) for high line or universal AC input. A multi-mode LLC converter is operable in a half-bridge mode or a full-bridge mode. For low line AC input, output voltage Vo, and PFC output Vdc, the LLC operates in full-bridge mode; for high line input, output voltage Vo and PFC output 2×Vdc, the LLC operates in half-bridge mode; for universal AC input, output voltage 2×Vo, and PFC output 2×Vdc, the LLC operates in full-bridge mode.

A power conversion system comprising, three full wave LLC resonant converters each of which has an associated high frequency isolation transformer, a full wave rectifier and an unfolding inverter, to provide a direct connection to a Medium Voltage (MV) three-phase grid for a high power photovoltaic system.