Harmonic Current Suppression for Open-Ending Winding PMSM Based on Voltage Injection

In this project, an effective harmonic current suppression strategy is developed for open-end winding permanent magnet synchronous motors (OEW-PMSMs) that are powered through a common DC bus. OEW-PMSMs offer advantages such as multilevel voltage output, higher voltage utilization, and enhanced fault tolerance, but they also suffer from significant harmonic distortion caused by air-gap field irregularities and nonlinear effects. Additionally, the presence of third-order harmonic voltages in the common DC bus further deteriorates the current waveform and degrades system performance. To address these challenges, a harmonic mathematical model is established to analyze and characterize the impact of different harmonic orders on the motor currents. Based on this model, a harmonic voltage injection method is proposed to actively compensate for the undesirable harmonics. By transforming the harmonic components into a decoupled d–q reference frame, the injection voltages can be precisely calculated using reference currents generated by closed-loop controllers. Simulation and experimental validations demonstrate that the proposed approach significantly suppresses harmonic currents, reduces torque ripple, and improves the dynamic response and overall performance of the OEW-PMSM drive system.

Keywords: Open-end winding permanent magnet synchronous motor (OEW-PMSM), common DC bus, harmonic voltage injection, harmonic current suppression.