弧焊逆变器功率变换回路的仿真

Simulation of Power Conversion Circuit in Arc Welding Inverter

建立了弧焊逆变器的器件级数学模型 ,对功率变换回路的瞬态过程进行了深入系统的仿真研究。在此基础上详细分析了不同电弧负载以及空载状态下磁芯的工作状况 ,此外还仿真分析了磁芯气隙、辅助阻容网络对磁芯工作状况的影响。仿真表明 ,弧焊逆变器近空载时磁芯工作状况最为恶劣。针对弧焊逆变器空载运行的特点 ,提出了PWM +PFM(脉宽调节 +脉频调节 )的空载控制策略。而通过适当调整磁芯气隙以及辅助阻容网络 ,可使磁芯工作状况得到显著改善 ,甚至部分位于B -H平面的第Ⅲ象限 。

In this paper,a mathematical model of arc welding inverter is set up on the device level.Based on simulating transient process of power conversion circuit thoroughly and systematically,working condition of magnetic core is analyzed in detail at various arc loads.Moreover,the effect of core gap and auxiliary RC network on working condition of magnetic core is carried out.Simulation results show that the working condition of magnetic core is worst at near zero load.A control technique,which combines PWM with PFM,is proposed to solve the problem that arc welding inverter runs at zero load.By adjusting core gap and employing an RC network,the working point of magnetic core is improved markly,and even situated at the third quadrant of B H curve.This design of transformer can be optimized theoretically.