电动汽车用IGBT及逆变器的电磁兼容性分析

Analysis of EMC Characteristics on IGBT and Inverter in Electric Vehicles

为了抑制电动汽车中的电磁干扰,提高整车的稳定性和安全性,建立了包含杂散参数的绝缘栅极双极型晶体管(IGBT)和三相电压型脉宽调制(PWM)逆变器的等效电路模型,计算得到了IGBT对周边设备的干扰传播增益;并通过仿真和实车实验分析了电动汽车用逆变器差模电压和共模电流干扰的时域、频域特征以及IGBT开关过程、PWM控制策略和干扰传播路径阻抗对干扰特性的影响。得出如下结论:逆变器的差模干扰主要是由IGBT开关过程和PWM控制策略所决定;逆变器的共模干扰本质上是由三相PWM脉冲之和不为0所引起,并且更多的受干扰传播路径阻抗特性的影响。上述模型和结论为整车电磁兼容性分析和干扰抑制打下了良好的基础。

In order to suppress the electromagnetic interference（EMI） in electric vehicle（EV） and consequently improve the stability and safety of EVs, we established equivalent circuit models of insulated gate bipolar transistor（IGBT） and pulse width modulation（PWM） inverter that took stray parameters into consideration. Based on the models, the interference propagation gains were calculated to estimate the influences of IGBT on other setups. Furthermore, the three-phase inverter used in EV was analyzed by simulation to get both time-domain and frequency-domain characteristics of interferences from the inverter＇s output differential mode（DM） voltage and its common mode（CM） current. The effects of IGBT switching, PWM control strategy, and propagation path impedances on the interference characteristics were also analyzed through simulations and practical EV experiments. It is obtained that the inverter＇s DM EMI is determined by IGBT switching processes and PWM control strategy, while its CM EMI is basically caused by the non-zero sum of three-phase PWM pulses, and it is affected more by the impedance of its propagation paths. The results have laid a foundation for the analysis and suppression of EV EMI.