Common-Mode Current Prediction and Analysis in Motor Drive Systems for the New Frequency Range of 2–150 kHz

Abstract

Due to the significant advances in fast switching semiconductor devices, harmonic emissions caused by the adjustable speed drives (ASDs) have been changed in terms of frequency range and magnitude. The frequency range of 2–150 kHz has been distinguished as a new interfering frequency range, disturbing the distribution networks. This article proposes a behavioral model of an ac motor to predict the common-mode (CM) current in ASDs. An approach is presented to calculate the parameters of the model, through which the dominant impact of each element at a specific frequency is considered. Moreover, along with the proposed motor model, a system modeling strategy is presented for filter design considerations at an emerging frequency range of 2–150 kHz. To verify the effectiveness of the proposed model, real-time experiments are conducted. The results prove that the introduced model can accurately predict the resonances of the CM loop created by the motor. Consequently, the proposed model is suitable for electromagnetic interference (EMI) filter design covering the 2–150-kHz standard.