Disclosed is a power converter including a generator configured to generate a sequence of output voltage waveforms, a resonant tank connected to the generator comprising at least one capacitor and at least one inductor, a transformer including a primary side connected in series with said series inductor and, the primary side being configurable to use at least one primary winding tap and a secondary side for connecting to a rectifying circuit for providing a rectified DC voltage to an output load circuit, a first switch and a second switch on the primary side connected to the primary winding, wherein the at least one primary winding is selected by the first switch or the second switch to select a different reflected output voltage by closing the first switch or the second switch.

The present invention increases the output voltage of a switching amplifier in a situation where the power supply voltage is limited. The switching amplifier includes first and second switches that are turned on and off in a complementary manner, and a capacitance, both ends of which serve as inputs to a power combiner. Both ends of the capacitance are connected to output ends of the first and second switches. The capacitance is supplied with power along with the operation of the first and second switches. As a result, an electric charge in the capacitance is used as a charge pump, and is used alternatingly for boosting or stepping down the output voltage depending on the operation frequency of the switching amplifier, thereby generating a rectangular voltage with a controlled wave height.

Unique systems, methods, techniques and apparatuses for a ZVT ZCT resonant converter with a variable resonant tank are disclosed. One exemplary embodiment is a system comprising a bidirectional resonant converter comprising an input/output terminal, a switching device coupled with the input/output terminal, a resonant circuit coupled with the switching device and including a variable inductor, an output/input terminal coupled with the resonant circuit, and a DC biasing circuit operatively coupled with the variable inductor. The variable inductor comprises a toroidal core, a first winding wound around the toroidal core and coupled with the switching device and the output/input terminal, a second core structured to overlap a portion of the toroidal core, and a second winding wound around the second core and coupled with the DC biasing circuit. The DC biasing circuit is controllable to vary the inductance of the variable inductor by saturating a portion of the toroidal core.

Unique systems, methods, techniques and apparatuses of zero-voltage transition pulse width modulation resonant converters are disclosed. One exemplary embodiment is a zero-voltage transition PWM resonant converter comprising a DC bus, a first switching device, a second switching device, a resonant tank circuit, an auxiliary circuit having a flying capacitor and a plurality of auxiliary switching devices, and a controller. The controller is structured to control the first switching device, the second switching device, and the plurality of auxiliary switching devices to provide resonant operation of the tank circuit effective to provide a substantially zero voltage condition across the first switching device when turning the first switching device on or off and to provide a substantially zero voltage condition across the second switching device when turning the second switching device on or off.

The present disclosure relates to a device comprising an inductive element and a first capacitive element series connected between a first node and a second node, a first MOS transistor connected between the first node and a third node configured to receive a reference potential, the second node being coupled directly or via a second MOS transistor to the third node, a second capacitive element connected between a fourth node and an interconnection node between the first capacitive element and the inductive element, a current generator configured to provide an AC current to the fourth node, and a switch connected between the fourth node and the third node.

A protection circuit of a resonant converter including first and second switches, where the protection circuit comprises: a comparator configured to (i) compare a direct current (DC) link voltage of the resonant converter with a voltage across both ends of one of the first or second switches and (ii) output one or more signals based on the comparison, and a microcomputer configured to detect whether zero voltage switching is performed, based on the one or more output signals from the comparator.

An apparatus (21) is described for facilitating emulated current-mode control of a resonant converter (1). The apparatus (21) comprises: an input (21) a for a first signal suitable for use in determining a phase of a resonant current, wherein the resonant current corresponds to a current in a resonant network (3) of the converter (1); an input (21b) for a second signal suitable for use in determining a target phase difference between the resonant current and a driving voltage, wherein the driving voltage corresponds to a voltage provided by a switch network (2) of the converter (1) to the resonant network (3); one or more outputs (21c, 21d) for one or more control signals for controlling operation of the switch network (2); and circuitry (21e-i). The circuitry (21e-i) is configured to: use the first signal in determining a first value, wherein the first value is related to a phase difference between the resonant current and the driving voltage; use the second signal in determining a second value, wherein the second value is related to the target phase difference; and set the one or more control signals based at least in part on a comparison of the first and second values, wherein the one or more control signals are for causing the phase difference to track the target phase difference.

A resonant inverter includes an input terminal, a first switch, a second switch, a transformer, a first resonant circuit, and a second resonant circuit. To the input terminal, an input voltage is applied. The first switch and the second switch are alternately turned on and off. The transformer includes a first winding and a second winding on a primary side. The first resonant circuit includes a first capacitive element and a first coil. The second resonant circuit includes a second capacitive element and a second coil. The first switch, the first winding, and the first resonant circuit constitute a first inverter circuit. The second switch, the second winding, and the second resonant circuit constitute a second inverter circuit. The input terminal is connected between the first winding and the second winding.

In an inverter circuit, more particularly in a single-phase inverter, soft switching is performed with a simple configuration to prevent switching loss of a switching element. A resonance circuit is configured by a resonant capacitor provided on the power supply side of a bridge circuit constituting a single phase inverter, a resonant inductor provided on the output side of the bridge circuit, and the bridge circuit. A resonance current passing through the resonance circuit allows zero voltage switching (ZVS) and zero current switching (ZCS) to be implemented at the rising time of main switching elements constituting the bridge circuit, and the zero voltage switching is implemented by means of zero voltage of the resonant capacitor at the falling time of the main switching elements constituting the bridge circuit.

A switch-mode AC-DC power converter includes a pair of input terminals, a pair of output terminals, and four switches coupled in a bridgeless totem-pole circuit arrangement between the pair of input terminals and the pair of output terminals. A control circuit is coupled to the four switches and configured to, during a cycle of an AC voltage input, turn on the first switch, turn off the second switch, and apply pulse-width modulation (PWM) control signals to the third and fourth switches. The control circuit is also configured to, during a zero crossing of the AC voltage input, supply a PWM control signal to the fourth switch to reduce a rate of voltage change across the second switch at the zero crossing to reduce common mode noise of the power converter.