A method and apparatus include a primary transformer coil, a secondary transformer coil, and a center tapped inductor coupled to the secondary transformer coil. A first switch may be in electrical communication with the center tapped inductor and may be configured to affect the first output voltage. A second switch may be in electrical communication with the center tapped inductor and may be configured to affect the second output voltage. In a particular example with an analog current (AC) output voltage, the two output voltages are out of phase to each other. In a direct current (DC) implementation, the transformer may be operated to output a positive and a negative output voltage. The apparatus may function as a resonant converter, or may operate in non-resonant mode. In one implementation, an H bridge may provide reactive power support. An inductor filter may be in electrical communication with the secondary transformer coil. Where desired, a diode bridge may be in electrical communication with the primary transformer coil.

Power conversion systems and methods to control a multiphase multilevel regenerative power converter with multilevel phase circuits that individually include multiple regenerative power stages with respective power stage outputs connected in series, each of the multiple regenerative power stages comprising a DC link circuit a switching rectifier coupled between a respective transformer secondary circuit and the DC link circuit, and a switching inverter coupled between the DC link circuit and the respective power stage output, including a controller that provides inverter switching control signals to control the respective switching inverters, provides rectifier switching control signals to control the respective switching rectifiers, and controls a non-zero phase relationship between the rectifier switching control signals of the respective switching rectifiers.

The present invention provides a power supply device and a power supply method for a DC electric arc furnace, wherein the power supply device comprises phase-shifting rectifier transformers, rectifying units and a regulator; through a structural design of a plurality of branches and a plurality of rectifying units at an output end of each phase-shifting rectifier transformer, and a structural design that outputs of the plurality of rectifying units are connected in parallel and then connected to a power supply short network of a DC electric arc furnace through bus bars, a current output topological structure is formed, which can provide a stable large current for one electrode assembly, and a plurality of current output topological structures can supply power to a plurality of electrode assemblies, so that requirement of a larger power supply current of the DC electric arc furnace can be satisfied; positions of top electrodes are judged and adjusted by the regulator according to real-time working parameters, which ensures that a lifting mechanism of the top electrodes can steadily perform the function of stabilizing arc burning for a long time; at the same time, output voltages and output currents of the rectifying units are adjusted by the regulator according to feedback of the real-time working parameters, so as to provide stable electric energy for the DC electric arc furnace.

The present invention provides a power supply device and a power supply method for a DC electric arc furnace, wherein the power supply device comprises phase-shifting rectifier transformers, rectifying units and a regulator; through a structural design of a plurality of branches and a plurality of rectifying units at an output end of each phase-shifting rectifier transformer, and a structural design that outputs of the plurality of rectifying units are connected in parallel and then connected to a power supply short network of a DC electric arc furnace through bus bars, a current output topological structure is formed, which can provide a stable large current for one electrode assembly, and a plurality of current output topological structures can supply power to a plurality of electrode assemblies, so that requirement of a larger power supply current of the DC electric arc furnace can be satisfied; positions of top electrodes are judged and adjusted by the regulator according to real-time working parameters, which ensures that a lifting mechanism of the top electrodes can steadily perform the function of stabilizing arc burning for a long time; at the same time, output voltages and output currents of the rectifying units are adjusted by the regulator according to feedback of the real-time working parameters, so as to provide stable electric energy for the DC electric arc furnace.

The power supply device includes a first winding, a second winding, a third winding, a fourth winding, a first AC-DC conversion unit, a second AC-DC conversion unit, a first power supply terminal and a second power supply terminal. The first and second windings are disposed on a secondary side of a multi-pulse transformer, and coupled to an input of the first AC-DC conversion unit. The first power supply terminal is coupled to an output of the first AC-DC conversion unit. The third and fourth windings are disposed on the secondary side of the multi-pulse transformer, and coupled to an input of the second AC-DC conversion unit. The second power supply terminal is coupled to an output of the second AC-DC conversion unit. Phases of output voltages of the first winding, the third winding, the second winding and the fourth winding are successively shifted left or successively shifted right for 15°.

A method and filter arrangement 400 for limiting distortion in a power supply system 420, said filter arrangement 400 being connected to a three-phase power supply device 420 supplying loads RL, said filter arrangement 400 comprising a phase shifting device 470 supplying said loads.

A line interface filter apparatus to couple a drive or group of drives to a shared multiphase AC bus, including individual phase circuits having an inductor coupled between a respective bus and drive phase lines, a tapped resistor coupled to the respective drive phase line, and a capacitor coupled between the resistor and a common connection of the capacitors of the individual phase circuits, where the capacitance of the capacitors is 5 to 15 times a per-phase equivalent capacitance of the drive or group of drives, and the resistance of the resistors is two times a damping ratio times a square root of a ratio of the filter inductance to the filter capacitance, where the damping ratio ζ is greater than or equal to 1.0 and less than or equal to 2.0.

An intelligent current control apparatus provides a current control for a power supply branch and a load. The intelligent current control apparatus includes at least one power conversion unit and a control unit. The control unit controls a total phase current, which is composed of a single-phase current and a household phase current in the same phase, to be less than or equal to a rated phase current of the power supply branch.

An intelligent current control apparatus provides a current control for a power supply branch and a load. The intelligent current control apparatus includes at least one power conversion unit and a control unit. The control unit controls a total phase current, which is composed of a single-phase current and a household phase current in the same phase, to be less than or equal to a rated phase current of the power supply branch.

An electric power system is provided that includes a three-phase to ten-phase step-up transformer. The transformer includes primary winding groupings, secondary windings, and third windings. The primary winding groupings include sub windings. Primary winding groupings are coupled to form a delta configuration and coupled to secondary windings and third windings, which may also be coupled to each other. The outputs at second ends of secondary windings and third windings are greater than the outputs at the second ends of primary windings. Diode pairs are connected to each other, each diode pair having an inner connection connected to one of the outputs of the transformer and first and second ends respectively connected to a positive dc bus and a negative dc bus. An inverter is connected to the d busses. The diode pairs operatively rectify the transformer output voltage to form a DC voltage with a reduced common mode voltage.