开关电源中电磁干扰的产生及其抑制

Electromagnetic Interference induced in Switching Power Supply and its Suppressing Techniques

电磁干扰对开关电源的效率和安全性及使用的影响日益成为人们关注的热点。开关电源对干扰的抑制在保证电子系统正常稳定运行方面具有极其重要意义。本文分析了开关电源中电磁干扰产生的原因和传播的路径。通过减小干扰源产生的干扰和切断干扰传播路径的方法,提出了抑制干扰的有效措施,并重点介绍了变压器的设计方法和制作方法。按照本文介绍的方法制作了一台反激式开关电源,实验结果表明,通过采用EMI滤波,合理改进变压器的设计和制作工艺等措施可以大大减小开关电源产生的电磁干扰。

Because the electromagnetic interference is an important factor which influences greatly the application of switching mode power supply,people pay more and more attention to it.In order to ensure systems operating stably and reliably,electromagnetlc interference induced by switching mode power supply must be reduced to a certain degree.In this paper,the cause of electromagnetic interference and its coupling path are analyzed,and some suppressing methods are mentioned.These methods are based on reducing electromagnetic interference induced by the interference sources and shielding the coupling path.A fly-back switching mode power supply using these methods mentioned has been made.The experimental results proved that electromagnetic interference can be reduced greatly by using EMI filters and designing and making transformer reasonably.