Hybrid Frame-Based Current Control Scheme for LC-Equipped PMSM With Non-Sinusoidal Back-EMF

Permanent-magnet synchronous machine (PMSM) drive with a sine wave LC filter has the features of low insulation stress and current harmonics. However, few studies consider the impact of back-electromotive force (EMF) harmonics on the LC-equipped PMSM drive system. The non-sinusoidal back-EMF can cause current harmonics, meanwhile, it also affects the stability analysis and high-frequency resonance suppression. In order to solve these two problems simultaneously, a hybrid frame-based current control scheme is proposed in this article. The quantitative effect of back-EMF harmonics on control behaviors is analyzed first. A virtual triple three-phase system with auxiliary currents is developed to decompose the fundamental and harmonic contents, which not only contributes to independent current harmonic regulation in multiple synchronous reference frames, but also simplifies system stability analysis considering non-sinusoidal back-EMF. Then, an active damping method based on stator current feedback is implemented in the stationary frame to suppress the resonance, and no additional passive components or sensors are required. Finally, experimental results are provided to verify the effectiveness and superiority of the proposed method.