Performance Analysis of High-Frequency Model of Electric Drive System under Different PWM Strategies

Electric drive systems encounter significant challenges in mitigating motor shaft voltage and bearing currents, primarily due to common-mode voltage (CMV) effects. While many studies have explored pulse width modulation (PWM) strategies to reduce CMV, the majority have focused on low-frequency domain analysis. This paper evaluates the high-frequency performance of the electric drive system considering various PWM techniques, including Space Vector PWM (SVPWM), various discontinuous PWM (DSPWM) methods, Active Zero-State PWM (AZSPWM), Remote-State PWM (RSPWM), and Near-State PWM (NSPWM). To ensure the applicability of the study, a detailed electric drive system model (including inverter, cable, and motor models) has been implemented and simulated. Moreover, a comparative analysis is conducted across a wide motor speed range (500 rpm to 3000 rpm), analyzing CMV dynamics, motor line-line voltage, shaft voltage, and total harmonic distortion (THD) of motor current. From the results, AZSPWM, RSPWM, and NSPWM demonstrate superior CMV and shaft voltage mitigation, making them suitable for reducing bearing current, while SVPWM offers the best current quality. The findings provide insights for selecting appropriate PWM strategies at different operating conditions. The simulation was conducted using MATLAB software, and the data was post-processed using ModeFRONTIER.