A system for controlling a plurality of power converters in a power system so as to turn each of the plurality of power converters into an ON state or an OFF state as a function of a sensed input power and a sensed output power such that one or more of the plurality of power converters in the ON state are operating in an optimal power efficiency range.

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.

A power switcher includes a first normally-off transistor that switches between interrupting and not interrupting a current path between first and second electrodes according to a drive voltage input to a first control electrode, a second normally-on transistor cascode-connected to the first transistor and including a second control electrode to which the second electrode of the first transistor is connected, a control voltage generator that generates a control voltage in accordance with a voltage between the first and second electrodes of the first transistor, and a drive voltage generator that generates a drive voltage equal to or lower than a withstand voltage of the first transistor in accordance with the control voltage.

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 multi-pulse transformer for an industrial machine, the multi-pulse transformer including a primary winding configured to receive a first voltage from a power source via a transformer, and a plurality of secondary windings configured to output a second voltage to a converter, the second voltage less than the first voltage. Wherein the multi-pulse transformer attenuates harmonic distortions by phase shifting each one of the plurality of secondary windings with respect to the primary winding. Wherein the multi-pulse transformer provides bi-directional flow of power.

A multi-pulse transformer for an industrial machine, the multi-pulse transformer including a primary winding configured to receive a first voltage from a power source via a transformer, and a plurality of secondary windings configured to output a second voltage to a converter, the second voltage less than the first voltage. Wherein the multi-pulse transformer attenuates harmonic distortions by phase shifting each one of the plurality of secondary windings with respect to the primary winding. Wherein the multi-pulse transformer provides bi-directional flow of power.

A first AC terminal, a first positive DC terminal, and a first negative DC terminal protrude from a first end portion in the length direction of a flat plate portion of a laminated bus bar. The first AC terminal, the first positive DC terminal, and the first negative DC terminal are arranged in alignment in this order from a third end portion toward a fourth end portion in a width direction of the flat plate portion. A second AC terminal, a second positive DC terminal, and a second negative DC terminal protrude from a second end portion of the flat plate portion in the length direction. The second AC terminal, the second negative DC terminal, and the second positive DC terminal are arranged in alignment in this order from the third end portion toward the fourth end portion.

Techniques for achieving a variety of selected direct current (DC) voltage outputs are disclosed. In one embodiment, a power generation system includes at least one multi-phase generator configured to generate an alternating current (AC) voltage. A plurality of diode rectifier circuits is coupled to the at least one multi-phase generator, which are configured to receive the AC voltage and convert the AC voltage to a DC voltage output. The power generation system includes configuration circuitry coupled to the plurality of diode rectifier circuits configured to configure the diode rectifier circuits in multiple configurations. For example, the configuration circuitry can configure the diode rectifier circuits in a series configuration to achieve a first DC voltage level, a parallel configuration to achieve a second DC voltage level, or a mixed series-parallel configuration to achieve a third DC voltage level.

Techniques for achieving a constant narrow range DC voltage are disclosed. In an embodiment, a system comprises at least one variable speed, multi-phased generator configured to generate an alternating current (AC) voltage. A plurality of diode rectifier circuits is coupled to the at least one multi-phased generator. The plurality of diode rectifier circuits are configured to convert the AC voltage to a direct current (DC) voltage. A plurality of high-power DC contactors is connected to the plurality of diode rectifier circuits. The plurality of high-power DC contactors is configured to configure outputs of the plurality of diode rectifier circuits in one of a parallel, series, and/or mixed parallel and series configuration. A controller coupled to the plurality of diode rectifier circuits and is configured to reconfigure the plurality of high-power DC contactors based on a control parameter of the at least one multi-phased generator.

Provided is a power supply apparatus that supplies power received from an external power supply to a load, the power supply apparatus comprising: a plurality of power supply circuitries, each of which has switching elements, that are allowed to supply power to the load separately; and a processor that controls a number of the power supply circuitries supplying power to the load according to a required power level of the load.