Study on conducted EMI suppression method in PWM adjustable speed system

To suppress the conducted EMI of PWM adjustable speed system, the generation mechanism and coupling route have been analyzed in this paper. According the differential generation mechanism, coupling route and source distribution of the interference, corresponding suppression measure were adopted from interference source and coupling route. The overshoot across the power electronics and the value of du/dt can be decreased by using snubber. According to the coupling route of the conducted EMI, the system can be divided into two parts by the converter and the conducted EMI propagation can be blocked from the view of leakage current and common mode voltage. An active filter can be used to compensate the leakage current and cancel the common mode voltage. A new filter configuration is developed for the conducted EMI noise suppression based on the theoretical analysis. The effectiveness of the proposed method is verified by the experimental results.