基于小波变换的滞环PWM变流系统EMI抑制策略研究

Research on EMI suppression method based on wavelet transform in hysteresis PWM converter system

针对滞环PWM(脉冲宽度调制,Pulse width modulation)变流系统在功率器件开关的过程中产生高频开关噪声的问题,提出了基于多分辨分析小波的信号滤波新方法,该方法运用小波多分辨分析方法实现了指令电流信号的去噪,同时提出了针对滞环PWM变流系统的信号去噪性能的评价指标.研究结果表明,该方法能够克服传统滤波方法的缺点,改善了滤波效果,提高了系统抑制EMI(电磁干扰,Electromagnetic interference)的能力,为大功率变流系统的EMI抑制提供了新的思路.

To reduce the high frequency switching noise generated by hysteresis current pulse width modulation （PWM） converter system, a new filter method based on multi resolution wavelet analysis is proposed in this paper. The method suppresses effective high frequency noise of three-phase sinusoidal voltage signal, and gives index value of signal noise suppression. The research results show that the filter method can not only overcome disadvantages of conventional filter, and improve filter performance, but also provide a new concept for EMI suppression.