杂散参数对IGBT串联阀开通过程的影响及抑制

Affects of Stray Parameters on Turn-On Process of Series-Connected IGBT Valves and Its Inhibition

由于电压源换流器(voltage source converter,VSC)的直流侧电压很高,绝缘栅双极型晶体管(insulated gate bipolar transistor,IGBT)阀组的开关过程非常短,导致交流侧输出电压变化率非常高。该电压作用于交流侧对地杂散电容,会增加IGBT在开通瞬间的电流过冲,造成很大的开通应力,影响IGBT的安全稳定运行;且电压越高,影响越大。为此,首先对杂散参数对IGBT串联阀开通过程的影响进行了理论分析;在此基础上提出在阀侧装设阻波器抑制杂散参数引起的电流过冲,并给出了阻波器设计方案。仿真和实验结果验证了该措施的有效性。

Due to the high voltage at DC side of voltage source converter（VSC） composed of series-connected insulated gate bipolar transistor（IGBT） valve sets and the very fast switching on/off process of IGBTs, the variation rate of output voltage at AC side is very high. When the output voltage with high variation rate is acted on stray capacitance to ground at AC side, it intensifies the current overshoot at the moment of switching IGBT on and leads to high current stress that endangers the secure and stable operation of IGBTs; the higher the DC voltage, the heavier the damage for IGBTs is. For this reason, firstly, the affects of stray parameters on the switching on process of series-connected IGBT valve sets are theoretically analyzed; on this basis it is proposed to install high-frequency damper at the valve side to suppress the current overshoot caused by stray parameters, and the design scheme of the damper is given. Both results from simulation and experiments show that the proposed measure is effective.