Power supply device and power supply method for direct current electric arc furnace

A power supply device for a DC electric arc furnace, comprising:

• phase-shifting rectifier transformers, rectifying units and a regulator;
• an input end of each phase-shifting rectifier transformer is connected to a power grid, a plurality of branches are led out from an output end of the phase-shifting rectifier transformer, each branch is respectively connected to one of the rectifying units, and outputs of the rectifying units are connected in parallel and then connected to a power supply short network of the DC electric arc furnace through bus bars, so that a current output topological structure is formed;
• an alternating current provided by the power grid is supplied to an electrode assembly of a plurality of electrode assemblies of the DC electric arc furnace after voltage reduction, phase shifting, rectification, chopping and confluence, wherein the electrode assembly comprises top electrodes and a bottom electrode, and the top electrodes are arranged on a lifting mechanism;
• the lifting mechanism is controlled by the regulator to adjust positions of the top electrodes;
• at the same time, output voltages and output currents of the rectifying units are controlled by the regulator;
• wherein each rectifying unit of the rectifying units comprises a rectifier and a DC chopper;
• an input end of the rectifier is connected to the output end of the phase-shifting rectifier transformer, an output end of the rectifier is connected to an input end of the DC chopper, an output end of the DC chopper is connected to a bus bar, and the bus bar is connected to the power supply short network;
• an input alternating current is rectified into a direct current by the rectifier, and an output voltage value and an output current value of the DC chopper are adjusted by the regulator.