Key Technology Of Large-tonnage Electroslag Furnace Low Frequency Power Supply

Large-tonnage electroslag furnace is based on the technology of electroslag remelting,is widely applied in the field of metallurgy a refining equipment,its on our country's equipment manufacturing technology,complete chinese-made 2025 vision enormous significance.Power supply basic traditional large-tonnage electroslag furnace are used to cover a high frequency transformer step-down to the electroslag furnace directly after provide the single phase or three phase power frequency 50 Hz alternating current,in actual operation,because of the working current is large,the electric furnace transformer between the electrodes in the furnace is longer than the lead,lead to impedance voltage drop is larger,combined with the single phase or three phase electroslag furnace due to realize three-phase load balance,waveform distortion,cause power grid harmonic pollution is serious,further reduces the power supply power factor,power factor usually only about 0.62 ~ 0.8,power consumption.To solve the above problems,this paper studies the principle of low frequency power supply,further analyzes the low-frequency electroslag furnace energy-saving and improve power factor.Then,electroslag furnace was designed with the principle of single-phase 92V/92 kA low-frequency power diagram,main circuit is composed of two 12 pulse of the double inverse star with buck parallel controlled rectifier circuit reverse parallel structure,with high performance high integration of DSP microprocessor as the core,adopts PID control,in the rectifier transformer on-load switch 27 coarse,fine tuning and thyristor phase control,realize the precise voltage and current control,the low frequency power supply system application of Siemens PLC S7-200 series as control core unit,the output and fault display TP700 with Siemens touch screen.Finally,in the control chip TMS320F2812 completed the related experiments,write and conducted experiment preliminary validation of the circuit,waveform analysis by means of low frequency power supply,this paper is proved the feasibility of the proposed electroslag furnace low-frequency power solutions.