差模特征频率共模干扰特性研究

Research on Common-mode EMI of Differential-mode Characteristic Frequency

电力电子装置的电磁干扰是电磁兼容性(Ectromagnetic Compatibility,简称EMC)研究的热点问题,如何准确识别干扰类型和产生机理是电磁干扰(Electromagnetic Interference,简称EMI)抑制的前提和难点。现以十二相整流发电机为研究对象,分析了整流发电机系统的等效电路和传导干扰特性,指出供电网络中的不对称会导致差模干扰(Differential-Mode Interference,简称DMI)转化为共模干扰(Common-Mode Interference,简称CMI),这种非本质的CMI往往会大于本质的CMI,并通过实验测量验证了理论分析的正确性。该研究结论可为供电系统中电力电子装置的干扰滤波器设计提供指导。

The EMI generated by power electronics equipment is a research hotspot of EMC.Accurately identifying the type and mechanism of EMI is the premise of the corresponding suppression,which is one of the difficuhies.A 12-phase rectifier generator system is studied.The equivalent circuit and the conducted interference characteristic of 12-phase rectifier system are analyzed.According to the analysis, the dissymmetry of power supply network will resuh in the conversion from Differential-Mode（DM） EMI into Common-Mode（CM） EMI.This kind of non-intrinsical CM EMI is often more serious than the intrinsical CM EMI.The results are also verified by experiments.The research achievements can be applied into the design of EMI filter for power electronics equipment.