Field-Weakening Control Strategy of High-Speed Permanent Magnet Synchronous Motor Based on Improved Voltage Phase Angle Control

Aiming at the poor voltage regulation ability of permanent magnet synchronous motor (PMSM) at high speed, an improved flux-weakening strategy based on the voltage angle control (VAC) method is proposed. The closed-loop transfer function of the control system is derived by using the small signal model method. To get over the low damping coefficient and system stability issue during acceleration, the proportional differential (PD) compensation strategy is introduced in the d-axis current regulator to realize inner loop feedback. It can effectively increase the system damping ratio and suppress the system resonance peak, resulting in reducing the current oscillation under the condition of speed fluctuation. Based on the principle of equivalent internal model controller and the frequency domain analysis, the key parameters of the compensator can be finally determined. Simulation and experimental results show that the proposed method can effectively improve the stability of the current inner loop and the anti-interference performance of the control system, particularly reduce the d-q axis current ripple.