复杂电子系统辐射EMI噪声机理分析与抑制

Noise Mechanism Analysis and Suppression for Radiated Electromagnetic Interference Noise

复杂电子系统产生的电磁干扰噪声包括传导EMI噪声和辐射EMI噪声,辐射EMI噪声会通过空间电磁场形式影响其它电子设备。针对复杂电子系统产生的辐射EMI噪声,该文分别建立5种辐射噪声理论模型及其等效电路,包括因接地不良引起的辐射噪声模型,因信号大环路引起的辐射噪声模型,因串扰引起的辐射噪声模型,因传输线缆引起的辐射噪声模型,以及因阻抗失配引起的辐射噪声模型。同时,还针对上述辐射噪声提出了相应的噪声抑制方法。实验结果表明,采用文中方法,某型助视器和测控保护装置能够通过GB 9254标准测试,噪声抑制效果分别可达20和21.5dB V/m,从而验证了方法的有效性。

Electromagnetic interference （EMI） generated by complex electronics systems included conducted EMI noise and radiated EMI noise. The operation of other electronic equipment was influenced by radiated EMI noise through space electromagnetic field. In order to analyze radiated EMI noise generated by complex power electronics systems, five theoretical models and equivalent circuits were proposed, including not-well grounding mechanism, large transmission loop mechanism, cross talk mechanism, transmission line mechanism and impedance mismatch mechanism. Furthermore, noise reduction methods were designed based on the above radiated noises. The experiment results show a visual acuity aid and protection supervisory equipment can pass the GB 9254 standard by employing the suggested approaches of the paper and its noise decreased 20 and 21.5 dBμtV/m, respectively, so the validity of the approaches was verified.