正弦频率调制降低开关电源传导EMI的实验研究

Reduction of Conducted EMI in Switching Mode Power Supplies with Sinusoidal Frequency Modulation

利用正弦频率调制技术从噪声产生源头上降低了开关电源传导电磁干扰,简单地分析了正弦混沌频率调制降低EMI噪声的原理,并试制了一台正弦频率调制反激变换器电源样机,给出了开关管电流信号的频谱以及传导干扰测试的结果。实验结果表明该技术能有效降低开关谐波峰值,具有应用的前景。

Reduction of conducted EMI in switching mode power supplies using sinusoidal frequency modulation scheme （SFMS） is proposed in this paper. The principle of suppressing EMI noise under SFMS is analyzed briefly and an experimental prototype of the flyback converter is constructed. The power spectral densities of the MOSFET＇s current and the conducted EMI test results are presented. The experimental results demonstrate that the SFMS can reduce the peak level of the switching harmonics effectively. The SFMS has applied prospect in switching mode power supplies.