Influence of High-Frequency Characteristics of Components on Leakage Current and Conducted EMI of Servo Motor Drive System

Leakage current and conducted electromagnetic interference (EMI) significantly impact the safe operation of servo motor drive systems (SMDSs). The impedance characteristics of the components in the circuit change considerably in the general frequency range studied for leakage current and conducted EMI. These variations at high frequency (HF) can result in conducted EMI and leakage current deviating from the expected results, necessitating further investigation. A method of impedance analysis is proposed in this paper, which can efficiently analyze the influence of HF characteristics of circuit components on leakage current and conducted EMI. The influences of Y-capacitor capacitance value and cable length on conducted EMI and leakage current are analyzed specifically. According to the HF characteristics of the Y-capacitor and the cable, it can be deduced that changes in leakage current and conducted EMI are associated with alterations in impedance characteristics. Finally, the accuracy of the theoretical analysis is verified by simulations and experiments.