Stability Analysis of LC-Equipped High-Speed Permanent Magnet Synchronous Motor System Considering Stator Resistance

LC-equipped high-speed permanent magnet synchronous motors (LC-HSPMSM) effectively mitigates switching harmonics, but its stability region is narrowed by resonance phenomena. While active damping (AD) methods can extend this stability region, they often require additional sensors and impose significant computational burdens. This paper proposes leveraging the inherent damping properties of the motor's stator resistance to expand the stability region. It models the system in the discrete domain, accounting for sampling and computational delays, and employs Nyquist diagram to determine the stability region. Furthermore, the study examines the variation in current-loop bandwidth within the stability region and analyzes how stator resistance and sampling delays affect this bandwidth. To further enhance the current-loop bandwidth, an AD method that effectively increases the stator resistance is introduced. Finally, experiments conducted on a 12-kr/min LC-HSPMSM platform validate the stability region, confirm the current-loop bandwidth variations, and demonstrate the efficacy of the proposed AD method.