According to one aspect, embodiments herein provide an AC-DC converter comprising a rectifier, a capacitor, a DC bus coupled to the capacitor, a plurality of first switches coupled to the DC bus, a plurality of second switches coupled between the rectifier and the first switches, a transformer having a primary winding and a secondary winding, the primary winding coupled to the plurality of first switches, the plurality of second switches, and the rectifier, and the secondary winding coupled to an output, and a controller configured, in response to a determination that the input AC power is acceptable, to operate the plurality of second switches and the plurality of first switches such that output DC voltage is maintained at a desired output DC voltage level, and operate the plurality of first switches such that a DC bus voltage on the DC bus is maintained at a desired DC bus voltage level.

A power converter for converting DC power to DC power includes an inverter stage having two or more switched inverters configured to receive DC power from a source and produce a switched AC output power signal. A transformation stage is coupled to receive the switched output power signal from the inverter stage, shape the output power signal, and produce a shaped power signal. A rectifier stage having two or more switched inverters coupled to receive the shaped power signal and convert the shaped power signal to a DC output power signal is included. A controller circuit is coupled to operate the power converter in a variable frequency multiplier mode where at least one of the switched inverters is switched at a frequency or duty cycle that results in an output signal having a frequency that is a harmonic of the fundamental frequency being generated by the power converter.

Provided are a short-circuit protection method and device for a half-bridge resonance converter. The method includes: a secondary-side current signal of the half-bridge resonance converter is detected, and the detected secondary-side current signal is converted into a corresponding first sampling voltage signal; whether a cycle-by-cycle protection is required in accordance with the first sampling voltage signal is determined; and a driving signal of the half-bridge resonance converter is compulsorily blocked during a preset cycle, if the cycle-by-cycle protection is required. Short-circuit protection may be performed for the half-bridge resonance converter, meanwhile a power density of the half-bridge resonance converter is satisfied.

A method includes configuring a hybrid converter to operate in a hybrid mode comprising four operating phases in response to an input voltage of the hybrid converter greater than a first threshold, configuring the hybrid converter to operate in a buck mode comprising two operating phases in response to the input voltage of the hybrid converter less than a second threshold, and configuring the hybrid converter to operate in a charge pump mode comprising two operating phases in response to the input voltage of the hybrid converter less than the first threshold and greater than the second threshold.

A secondary-side rectification and regulation circuit includes a secondary-side transformer winding, a full-wave rectifier circuit and a control unit. The full-wave rectifier has a first pair of controllable rectifiers including a first transistor connected to a first terminal of the secondary-side transformer winding and a second transistor connected to a second terminal of the secondary-side transformer winding. The control unit is operable to control switching of the transistors of the full-wave rectifier so that the full-wave rectifier (a) generates a rectified output for supplying a load by rectifying current through the secondary-side transformer winding or voltage across the secondary-side transformer winding and (b) regulates the rectified output.

A high voltage generator is provided. The high voltage generator includes an inverter circuit coupled to receive a direct-current (DC) input voltage, a resonant circuit coupled to the inverter circuit, a transformer coupled to the resonant circuit and also coupled to provide a high voltage output to a high voltage device, and a phase control circuit coupled to receive a voltage across and a current through the resonant circuit and also coupled to the inverter circuit. The phase control circuit generates control signals to drive the inverter circuit. The control signals drive the inverter circuit to keep the resonant circuit operating in an inductive region.

A power conversion system including a power conversion unit, a power circuit and a precharge circuit is provided. The power conversion circuit includes an input port, an output port, switching power conversion units and at least one storage device. The storage device is connected between the input and output ports in series. The power circuit is electrically connected to the power conversion circuit for receiving the input voltage and outputting a supply voltage to the power conversion circuit, and the power circuit includes a magnetic element. The precharge circuit precharges the storage device. The precharge circuit includes a winding and a rectifier filter circuit connected to each other. The winding is coupled to the magnetic element for receiving a conversion voltage. The rectifier filter circuit is electrically connected to the storage device so as to receive the conversion voltage and output a charge voltage to the corresponding storage device.

A half bridge DC-DC converter device includes a primary circuit and a secondary circuit, which include separate windings that are disposed around a magnetic core. The first circuit includes two switches and a drive circuit to turn the two switches on and off in an alternating fashion. The primary circuit further includes two thermal regulating components to regulate the current at the base of the two switches over a range of operating temperatures. The regulation of base current over a range of different operating temperatures results in the half bridge converter device being efficient and maintaining a stable switching frequency over the operational temperature range.

A power converter having a parallel resonant circuit, includes an inverter, a resonant circuit, a transformer comprising a primary circuit and a secondary circuit, control means for the inverter, the inverter being connected to the resonant circuit, which is intended to be connected to an output load via the transformer, the power converter wherein the inverter comprises a first half-bridge and a second half-bridge in parallel with the first half-bridge, a first inductor between the first half-bridge and the resonant circuit, a second inductor between the second half-bridge and the resonant circuit, and in that the first and second inductors have the same inductance and are coupled in the opposite direction to one another.

A power converter having a parallel resonant circuit, includes an inverter, a resonant circuit, a transformer comprising a primary circuit and a secondary circuit, control means for the inverter, the inverter being connected to the resonant circuit, which is intended to be connected to an output load via the transformer, the power converter wherein the inverter comprises a first half-bridge and a second half-bridge in parallel with the first half-bridge, a first inductor between the first half-bridge and the resonant circuit, a second inductor between the second half-bridge and the resonant circuit, and in that the first and second inductors have the same inductance and are coupled in the opposite direction to one another.