Conducted EMI in PWM inverter for household electric appliance

This paper presents the characteristics of the conducted EMI in the PWM inverter for household electric appliances and proposes a new active common-mode EMI filter. The conducted EMI spectrums are measured with changing the active/passive filter stages and the common-mode EMI is extracted from the total conducted EMI spectrums in order to identify the dominant source of the conducted EMI. For better understanding of the conducted EMI, the noise sources are identified and the characteristics of the noise source and its propagation paths are investigated from the conducted EMI spectrums measured. Based on the measurement and analysis of the conducted EMI in the PWM inverter, the effective method and procedure of designing filter stages are developed in order to attenuate the conducted EMI effectively.