基于最坏情况测试的开关电源滤波器研究

Research on switching power supply filter based on worst-case measurement

为了抑制开关电源的传导干扰,在开关电源的线路上增加电磁干扰(EMI)滤波器。根据最大阻抗失配原理选择EMI滤波器时,开关电源的阻抗不确定,故很难快速选出满意的滤波器。通过分析滤波器的主要参数及最坏情况测试方案,提出一种基于最坏情况衰减曲线选择EMI滤波器的方法。根据该方法可以对EMI滤波器的实际效果做出有效估计,避免了滤波器选择不合理导致的重复、费时的测试。

In order to suppress conducted interference of switching power supply, the EMI filter was increased in switching power supply lines. It is difficult to select a satisfactory filter quickly based on the principal of maximum impedance mismatching, because the impedance of switching power supply is uncertain. Through analysis of the main parameters of the filter and the worst-case measurement, a method to select EMI filters by worst-case attenuation was presented. According to this method, a valid estimate of the actual effect of EMI filter could be made,avoiding the duplication and time consuming tests caused by unreasonable filter selection.