A Novel Method of High-Speed PMSM Drive Based on LCL Filter

The performance of the current loop in the high-speed permanent magnet synchronous motor deteriorates due to the characteristics of the small inductance and low carrier ratio. On the one hand, the control accuracy and the efficiency of the current loop are reduced because of the current harmonics caused by the small inductance. On the other hand, the impact of cross-coupling is increased as a result of the low carrier ratio. In order to reduce the current harmonics and enhance the performance of linear control in the high-speed PMSM control system, a three-phase LCL filter method is proposed in this paper. First of all, the mathematical model of the LCL filter containing the stator inductance is built and quantitatively analyzed for parameter selection of the filter. Secondly, the parameters are optimized by analyzing the magnitude-frequency characteristic of the LCL filter. A passive damping strategy is implemented to suppress the resonance which is introduced by the LCL filter. Thirdly, aiming at the problem that the impact of cross-coupling is increased under low carrier ratio of the high-speed PMSM, a method of complex vector PI controller is presented to realize the current decoupling, and a virtual resistor strategy is implemented to increase the stability of the current loop. The simulation results are finally carried out to verify the effectiveness and correctness.