开关电源的电磁兼容性设计

EMC design of switching power supply

对开关电源的电磁干扰波形进行了分析,建立造成共模干扰、串模干扰的电路模型, 然后提出了具体解决方案:利用单级或双级EMI滤波器滤除共模干扰和串模干扰,并介绍了选择EMI滤波器中元器件的方法.实验表明: 利用简易的EMI滤波器可将电磁干扰衰减40 dBμV;使用改进后的EMI滤波器,能将电磁干扰衰减50～70 dBμV.

This paper analyses the EMC wave of the switching power supply and establishes the circuit model that results in common mode interference and series mode interference. Then provides the concrete solution., making use of single or double level EMI filters can filter common mode interference and series mode interference effectively. Finally, it introduces the method to choose the device parameter in the EMI filters. The experiment indicates that it can reduce EMI by 40 dBμV by the simple EMI wave filter. However,using the improved EMI wave filter can reduce EMI by 50～70 dBμV.