Research On Temperature Control For Copper Bar Diathermanous With Induction Heating Power Supply

Heating copper bar is an important stage in the die forging process. After heating the bar,punching press, forging press or other forms are used to forge and press workpiece into othershapes. Heating is generally divided into two broad categories-flame heating and electricheating As copper bar heating before forging technology in domestic started late, and furnacehad a simple structure and fuel cost was low, there were plenty of factories using flameheating in Jiangsuand Zhejiangprovinces in1990’s. However, the advantage of flame heatingwas offset with the development of national economy and the increment of energy price. Withthe benefit of good working environment, less pollution and high thermal efficiency,induction heating has been applied widely in industry.The paper analyses copper bar heating models, using the heating of copper bar asresearch target. The circuit configuration is improved to solve the defect of low frequency,high temperate error, big size and low efficiency of current used medium frequency inductionheating power supply. In the main circuit design, three-phase uncontrolled rectifier with Buckchopping is used, and single phase full-bridge series resonance converter is adopted. Buckconverter works in hard switch will cause high switch loss. The improved circuit of Buckconverter with soft switch is used. An coupled inductor with the main inductor, a auxiliaryinductor, and a diode are added in the proposed converter. Soft switch can be realized withoutadding auxiliary switch to construct auxiliary circuit, so its structure is simple and it is easy tocontrol. The control system is made of double closed loops and main circuits have beensimulated.This paper designed a temperature control for copper bar diathermanous with inductionheating power supply with60kHz/60kW based on DSP, and finished the DSP system design.Experiments had been carried out.