船用电子设备中开关电源的电磁辐射

Electromagnetic Radiation of Switching Power Supply in Marine Electronic Equipment

为研究RC缓冲电路对开关电源电磁辐射的影响,对buck型开关电源基本电路进行仿真,对比加入RC缓冲电路前后开关节点处的谐振波形,通过傅里叶变换分析RC缓冲电路对电磁辐射的影响规律。通过分析得到以下结论:RC缓冲电路在低频段可有效降低buck型开关电源的电磁辐射水平,在高频段反而会使电磁辐射增强;减小RC缓冲电路与二极管构成的回路面积可降低buck型开关电源的电磁辐射水平。通过试验验证结论的正确性,可为开关电源中RC缓冲电路的使用提供参考。

The simulation of a basic DC-DC buck converter with/without a snubber circuit is performed to investigate the effect of the snubber circuit.The resonant waveforms at the switch node is compared and analyzed in their Fourier transforms.The analysis indicates that the RC snubber circuit can effectively reduce the electromagnetic radiation of DC-DC buck converter in lower frequency range but will increase it at higher frequency end,and keeping the area of the RC snubber circuit-diode loop small will make the electromagnetic radiation of DC-DC buck converter smaller.The conclusion is verified by experiments.