A method and related apparatus for extending a DC voltage range of a rectifier circuit for the supply, from an AC grid, of a DC load which is connected to a DC rectifier output of the rectifier circuit, wherein an AC rectifier input of the rectifier circuit is connected via a grid connection point to the AC grid, wherein the rectifier circuit includes an AC/DC converter having an AC input and a DC output, wherein the AC/DC converter includes a converter circuit having semiconductor switches and freewheeling diodes connected in an antiparallel arrangement thereto, wherein an inductance is connected between the AC input of the AC/DC converter and the grid connection point. The method includes setting a desired DC operating voltage U.sub.DOC,soll on the DC output of the AC/DC converter or on the DC rectifier output, or both, by an actuation of semiconductor switches of the AC/DC converter, wherein, when the desired DC operating voltage U.sub.DC,soll lies below a value of an amplitude .Math..sub.4 of an alternating voltage on the AC input of the AC/DC converter, the semiconductor switches of the AC/DC converter are actuated for an exchange of reactive power Q.sub.1(t) with the AC grid, which has a voltage-lowering effect upon the amplitude .Math..sub.4 of the AC voltage at the AC input of the AC/DC converter, such that the amplitude .Math..sub.4 approaches the desired DC operating voltage U.sub.DC,soll, and wherein the exchange of the reactive power Q.sub.1(t) with the AC grid is executed during or shortly before an electrical connection or an electrical isolation of the DC load to or from the rectifier circuit.

A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.

A precharge system and method are provided. The precharge system comprises a load circuit, a precharge circuit and a control circuit. The load circuit comprises an input terminal, an input switch and a bus capacitor. The precharge circuit comprises a precharge resistor and a precharge switch. The precharge method comprises: during the load circuit being in a precharge mode, controlling the input switch to be in an off state, and controlling the precharge switch to switch between the on and off state for multiple times; and during the load circuit being in a work mode, controlling the input switch to be in an on state. During the load circuit being in the precharge mode, when the precharge switch is in the on state, a consuming power of the precharge resistor is larger than a threshold power and is smaller than or equal to a limit power of the precharge resistor.

The present disclosure relates to a power converter for use in a host vehicle. The power converter comprises a DC link, a DC link capacitor, and a pre-charge circuit configured to charge the DC link capacitor. The pre-charge circuit comprises a boost converter comprising a switch and inductor coupling terminals configured to couple to an inductive component external to the power converter.

Embodiments of the disclosure include an electrical assembly. The electrical assembly can include a converter including a DC side and an AC side, the DC side configured for connection to a DC network, the AC side configured for connection to an AC network, the converter including at least one switching element; a circuit interruption device operably connected to the AC side of the converter; a DC voltage modification device operably connected to the DC side of the converter, the DC voltage modification device including a DC chopper; and a controller configured to selectively control the or each switching element, the circuit interruption device and the DC voltage modification device, wherein the controller is configured to be responsive to a converter internal fault by carrying out a fault operating mode.

Provided is a power supply device including a capacitor, a pre-charge circuit and a control circuit. The capacitor is connected in series with a contactor that is connected between an inverter driving a motor and a battery and that switches on or off power supply from the battery to the inverter, and is connected in parallel with the inverter. The pre-charge circuit is connected in parallel with the contactor and pre-charges the capacitor. The control circuit controls the pre-charge circuit and the contactor. The control circuit includes a sensor that measures the voltage of the battery and the voltage of the capacitor, and determines whether the pre-charge is necessary according to whether a ratio of the voltage of the capacitor to the voltage of the battery is equal to or less than a target value.

This power conversion device has: a main breaker and a main electromagnetic contactor connected to a main power supply; a converter body having a switching element; a power supply-side reactor and a device body-side reactor connected to the main electromagnetic contactor; a current detector; a smoothing capacitor; a DC voltage detector that detects a voltage of the smoothing capacitor; a control unit; and accessories. The accessories have: a power-supply phase detection transformer that detects the phase and the amplitude of a power supply voltage; a current limiting resistor that suppresses rush current to the smoothing capacitor at an initial turning-on stage of the main power supply; an electromagnetic contactor which is for turning on current limiting operation and which connects the current limiting resistor and the main power supply; and a filter circuit that removes current ripples caused by switching of the switching element. The main breaker, the main electromagnetic contactor, and an input terminal of the power-supply phase detection transformer in the accessories are connected to one another. The power supply-side reactor, the device body-side reactor, and a filter terminal in the accessories are connected to one another.

A power conversion system comprises a plurality of power modules, each including a power input end; a charging input end; a power output end; at least one power conversion unit, each including an AC/DC conversion unit and at least one DC-Bus capacitor and being connected to the power input end and the power output end; and a pre-charging unit connected to the charging input end for receiving direct current and connected to the DC-Bus capacitor. The pre-charging unit starts to charge the DC-Bus capacitor of one of the power modules when said power module breaks down or the load of the power conversion system is light so that no current flows through the AC/DC conversion unit. The power input ends of the power modules are connected in series and then connected to an AC power source, and the power output ends of the power modules are connected in parallel.

A power supply system includes a plurality of power conversion devices connected in parallel with each other, a load state detector to detect an operating state of a load connected to the DC system, and a command generator to generate a distribution voltage command Vref Each of the power conversion devices includes a DC voltage controller to generate an output power command Pdc_ref based on a voltage of the DC system and the distribution voltage command Vref, and an AC/DC converter to convert AC power received from the main power source based on the output power command Pdc_ref and output the converted power to the DC system. The command generator generates the distribution voltage command Vref such that loss of the load connected to the DC system is reduced, based on a detection result of the load state detector.

The present disclosure provides a three-phase AC/DC converter aiming for low input current harmonic. The converter includes an input stage for receiving a three-phase AC input voltage, an output stage for at least one load, and one or more switching conversion stages, each stage including a plurality of half bridge modules. The switches in each module operate with a substantially fixed 50% duty cycle and are connected in a specific pattern to couple a DC-link and a neutral node of the input voltage. The AC/DC converter further includes one or more controllers adapted to vary the switching frequency of the switches in the switching conversion stages based on at least one of load voltage, load current, input voltage, and DC-link voltage. The converter can also include one or more decoupling stages, such as, inductive components adapted to decouple the output stage from the switching conversion stages.