A system includes a first DC rail and a second DC rail, and a rectifier coupled with the first and second DC rails. A multilevel converter is also coupled with the DC rails and operable to limit input current harmonics to the rectifier. Differences between voltage phase and current phase in AC electrical power supplied to the system are compensated via closed loop control of a voltage output of the multilevel converter.

A system includes a first DC rail and a second DC rail, and a rectifier coupled with the first and second DC rails. A multilevel converter is also coupled with the DC rails and operable to limit input current harmonics to the rectifier. Differences between voltage phase and current phase in AC electrical power supplied to the system are compensated via closed loop control of a voltage output of the multilevel converter.

The invention relates to a driving circuit comprising a first bridge circuit, a second bridge circuit, a first protection device and a second protection device. The first bridge circuit comprising a first positive input terminal, a first negative input terminal, a first positive output terminal and a first negative output terminal is coupled to an AC voltage source to output a first voltage. The second bridge circuit comprising a second positive input terminal, a second negative input terminal, a second positive output terminal and a second negative output terminal is coupled to the AC voltage source to output a second voltage. The second and the first negative output terminals are both coupled to the ground potential. The first protection device is coupled between the second positive input terminal and the AC voltage source. The second protection device is coupled between the second negative input terminal and the AC voltage source.

A power supply circuit comprises control signal circuitry comprising power control command generation means for receiving or generating a power supply command and for generating internal switching control signals according to the power supply command for controlling power supply, and a first galvanic separation stage receiving at its input the internal switching control signals and producing at its separation output output control signals. It also comprises power control circuitry with power input terminals connectable to an input power supply, a signal input connected to said separation output, a semiconductor power switch for switching on and off power drawn from said power input terminals in accordance with the output control signal from said signal input, a first transformer comprising a first primary winding connected to said semiconductor power switch and to one of said power input terminals and a first secondary winding inductively coupled with said first primary winding, and a power output circuit connected to said first secondary winding and having power output terminals for supplying controlled supply power.

This disclosure provides a bipolar-independent DC power delivery system. The bipolar-independent DC power delivery system includes a grid-tied power electronic converter, a bipolar DC power busway, and a power conversion unit. The grid-tied power electronic converter connects to a medium-voltage distribution grid and converts the distribution grid voltage to two independent DC voltages with same magnitude and opposite polarities. The bipolar DC power busway connects two independent DC voltages generated from the grid-tied power electronic converter to the power conversion unit. The power conversion unit can receive or send electric power from one or two independent DC voltage(s). The proposed DC power delivery system can continue to operate at de-rated power when one of two independent DC voltages fails.

A power converter is proposed for converting a mains input into an output for driving at least one load, in particular for driving a pair of electrodes in a treatment chamber of a pulsed ohmic heating or other pulsed electrical fields technology (PEF) based cooking appliance, the power converter, also able to be put in use as a resonance converter, comprising a circuit at least composed of a rectifier unit arranged for receiving a mains input and for converting the mains input into a pulsating voltage, output for driving the load; at least one high frequency filter unit connected in a parallel branch with the rectifier unit; as well as a bridge inverter unit comprising at least one bridge branch connected in parallel with the rectifier unit and connected with the at least one load; wherein the at least one bridge branch comprises two switches connected in series, wherein an output terminal is provided between the two in series connected switches in the at least one bridge branch, the output terminal of the at least one bridge branch being connected with the load; and wherein a current injection unit is provided between the output terminal and the rectifier unit.