开关电源EMI滤波器的不稳定性的研究

Analysis of the Instability of EMI Filters in Switched Mode Power Supplies

为了研究EMI滤波器与开关电源匹配过程中可能引起的不稳定性问题,结合滤波器理论和自动控制理论,利用PSpice,Matlab等仿真工具,深入探究了不稳定性的产生原因和解决方法。研究表明,不稳定性在时域中表现为发散振荡的波形。常用的解决不稳定性问题的方法有在滤波器电路里加入RC,RL阻尼电路,从而改变滤波器的传递函数和输出阻抗波形,最后在仿真基础上验证了两种电路的有效性。

Based on the concept of negative dynamic resistance of converters, the essence of the instability in mating the EMI filter and switched mode power supplies were analyzed. The reason and solving method were studied in terms of the EMI theory and automatic control theory. In order to understand what instability means, PSpice was applied to model it. Then two damping methods, namely RC and RL damping circuits, were proposed and simulated using Matlab. The methods turn out to be effective.