Research on vibration analysis and active suppression strategies for permanent magnet synchronous motors

Abstract

In PMSM drives, inverter switching generates low-order harmonics and modulation harmonics, which are primary sources of radial electromagnetic force waves, torque ripple, and audible noise, while also deteriorating controller effectiveness. To mitigate low-order harmonics, a harmonic analytical model is developed. By transforming harmonic components into a rotating reference frame synchronized with each harmonic order, they become DC signals, which are extracted using low-pass filters. Based on the harmonic voltage model, corresponding compensation voltages are calculated and injected in reverse polarity to actively cancel the original harmonics. For high-frequency sideband harmonics arising from PWM carrier effects, random PWM is adopted to reduce the peak amplitude around the switching frequency and spread the spectral energy over a broader range, thus preventing energy concentration and reducing acoustic noise. The combination of active harmonic injection and random modulation offers a practical solution for suppressing vibration and noise in PMSM systems.