抑制共模电磁干扰的并联有源补偿电路设计

讨论了并联有源共模电磁干扰抑制中的两种不同补偿电路结构,通过建立带有补偿电路的单相半桥逆变器共模电流等效模型,详细介绍了两种补偿电路的设计过程,讨论了影响补偿电路补偿效果的两个因素,实验验证了设计补偿电路能够产生与噪声源共模电流大小相等方向相反的补偿电流。

A scheme of reducing common mode EMI based on push-pull compensating circuit

With the application of high-speed high-power switch devices,severe electromagnetic interference(EMI) is produced due to high dv/dt and high di/dt caused by high speed switching of power devices.An active common mode EMI suppression technique with an external compensating circuit is studied.Two different compensating circuits where the DC biased voltage source is provided by DC bus voltage of converter or external electric supply,which are named as direct and indirect parallel compensating circuit,are introduced.The common mode equivalent model of single-phase half-bridge converter with two kinds of compensating circuit is studied.The calculating process of output capacitor and coupling capacitor in active compensating circuit is illustrated by using the common mode current equivalent mode based on noise source in parellel.And two facts of influence the suppression effect,which are compensating circuit output capacitor and driving resistance are analysised.Experiments validate that the compensating circuit can output the compensating current with equal-large anti-phase of the common mode current produced by converter.