Prediction and Analysis of PWM-Induced Current Ripple of PMSM at Low Switching-to-Fundamental Frequency Ratios

This article addresses the challenge of current ripple in permanent magnet synchronous machines (PMSMs), predominantly caused by the pulse width modulation (PWM) effect of voltage source inverter. This phenomenon is especially prominent at low switching-to-fundamental frequency ratios (SFFRs), leading to significant noises and decreased efficiency. This article proposes a flux-linkage-based discrete method to accurately and fastly predict PWM-induced current ripple in PMSMs. Ripple patterns and various influencing factors are studied in-depth based on the proposed method. Experimental studies to validate the proposed prediction method are presented, confirming its effectiveness, especially in scenarios where traditional methods fall short due to low SFFRs.