An exemplary inductive power transfer system having a transmitter coil and a receiver coil. A transmitter-side power converter having a mains rectifier stage powering a transmitter-side dc-bus and controlling a transmitter-side dc-bus voltage U.sub.1,dc. A transmitter-side inverter stage with a switching frequency f.sub.sw supplies the transmitter coil with an alternating current. A receiver-side power converter having a receiver-side rectifier stage that rectifies a voltage induced in the receiver coil and powering a receiver-side dc-bus and a receiver-side charging converter controlling a receiver-side dc-bus voltage U.sub.2,dc. Power controllers that determine from a power transfer efficiency of the power transfer, reference values U.sub.1,dc*, U.sub.2,dc* for the transmitter and receiver side dc-bus voltages. An inverter stage switching controller controls the switching frequency f.sub.sw to reduce losses in the transmitter-side inverter stage.

A converter circuit includes an inverter and a controller. The inverter is configured to receive an input voltage and to convert the input voltage into a primary-side alternating-current (AC) voltage in a first inversion mode or a second inversion mode. Each of a first switch unit and a second switch unit in the inverter includes switches. When the converter circuit works in the first inversion mode, the controller controls switches of the first switch unit and the second switch unit to cooperatively switch on and switch off periodically according to an output voltage corresponding to the primary-side AC voltage. When the converter circuit works in the second inversion mode, the controller controls the first switch unit to operate independently, in which the switches of the first switch unit switch on and switch off periodically.

A resonant power converter is provided with capacitive switching mode protection. The converter produces output current and voltage according to an operating frequency, which is desirably maintained above a resonant frequency for the power converter. A controller regulates the operating frequency based on an output current relative to a reference value, which may be provided via a dimming interface. A capacitive switching mode is determinable, based on a positive relationship in a detected direction of change in an output value relative to a detected direction of change in the operating frequency. When the capacitive switching mode is determined, a preceding operating frequency is enacted and the controller disables regulation of the operating frequency therefrom. Inductive mode switching is determinable with a negative relationship between detected direction of change in the output value relative to direction of change in the operating frequency, wherein regulation of operating frequency is renewed.

An inverter producing an alternating current from a direct current source has a primary stage coupled to the direct current source having a step-up transformer, a first switching circuit coupling the direct current to the transformer primary and a rectifier coupled to a secondary of the transformer for producing a DC voltage; a controller for the first switching circuit providing pulse drive signals to control switches of the first switching circuit to cause current to flow in the transformer primary and induce an alternating current in the transformer secondary; a secondary stage receiving the DC voltage having a second switching circuit and a controller for the second switching circuit for generating control signals to cause current through the second switching circuit to flow in alternate directions thorough the load. In one embodiment the alternating current period is divided into time slices and the switches of the first switching circuit are duty cycle modulated at different duty cycles in each time slice. A second embodiment switches series-connected primary windings of a multi-tap transformer.

An electronic half-bridge ZETA converter may include a transformer, wherein a half-bridge is connected to the primary winding of transformer, and wherein a respective capacitance and a respective diode are associated with the half-bridge switches. Moreover, the converter includes a ZETA converter which is connected to secondary winding of transformer, so that the ZETA converter includes a first inductance, which includes the magnetization inductance of transformer, and a second inductance. Finally, the converter includes a control unit which drives the half-bridge switches with four time intervals that are repeated periodically. Specifically, during the fourth time interval the first and the second switch are opened, so that the capacitance associated with said second switch is charged and the capacitance associated with said first switch is discharged, enabling a zero voltage switching.

A DC-to-DC converter includes a voltage converter having: a capacitance; at least one inductor configured to store energy and exchange stored energy with the capacitance; and a switching element configured to switch on and off a current flowing through the inductor and change direction of the current at each switching. The inductor includes a variable inductor whose inductance decreases with increase in the current.

A power supply comprises at least one input to couple the power supply to a power source. The power supply also comprises at least one switched-mode power circuit configured to extract electrical energy from the power source, the electrical energy to be transferred to a load. The power supply additionally comprises at least one control module coupled between the at least one input and the at least one switched-mode power circuit. The control module is configured to control operation of the switched-mode power circuit to regulate a voltage-to-current ratio at the at least one input of the power supply.

A bidirectional or unidirectional DC-DC converter includes a primary stage and a secondary stage. The primary stage is configured to receive or output a first DC voltage. The primary stage includes a first switching network configured to convert the first DC voltage to a first alternating current (AC) voltage or vice versa. The DC-DC converter also includes a transformer having primary windings and secondary windings. The primary windings are in electrical communication with the first switching network. The transformer is configured to convert between the first AC voltage and a second AC voltage. The DC-DC converter also includes a secondary stage that has a second switching network. Characteristically, the second switching network and the transformer operate as an interleaved converter to convert the second AC voltage to an output DC voltage or vice versa. Advantageously, the required series inductance for this interleaved converter is integrated into the transformer.

Each phase of a multi-phase voltage converter includes a power stage, passive circuit, synchronous rectification (SR) switch, and control circuit. Each passive circuit couples its power stage to an output node of the voltage converter, and is switchably coupled to ground by the SR switch. The current through the SR switch has a half-cycle sinusoidal shape with a resonant frequency determined by the reactance of the passive circuit. The control circuit generates signals to control switches within the power stage and the SR switches. The control circuit measures current through the SR switch of each phase, and determines which of the phases has SR switch current which returns to zero the quickest. This phase is identified as a master, and the other phases of the voltage converter are aligned to this master phase such that none of the SR switches is turned off when negative current is flowing through it.

An electric power converter includes an inverter, an insulating transformer, and a rectifier. The inverter converts an input DC voltage, supplied from a DC power supply, to an AC voltage outputted at an AC output side of the inverter, and includes at least one semiconductor switching device made of wide bandgap semiconductor material configured to carry out turning-on and turning-off operations at a specified frequency to thereby invert the DC voltage to the AC voltage at the specified frequency; and at least one freewheeling diode made of silicon-based semiconductor material respectively connected to the at least one switching device in inverse parallel.