Current loop bandwidth expansion strategy of AC servo motor based on predictive current compensation

To enhance the current loop bandwidth of the AC servo motor, a current predictive control scheme based on current predictive compensation and a double sampling and double PWM duty cycle update mode is put forward. Firstly, the current prediction mathematical model is constructed by the AC and direct axis voltage equations of the permanent magnet synchronous motor, and the current prediction compensation equation is derived by reducing the motor parameters within the current prediction model. Subsequently, thedandq-axis current prediction evaluation function is designed, and the recursive expression of the motor parameter in the current prediction compensation equation is obtained by aiming at minimizing the evaluation function. Then, a correction factor self-tuning approach is proposed to guarantee the convergence consistency of the motor parameters. Finally, the dual sampling dual PWM duty cycle update mode is employed to shorten the digital sampling delay time. Experimental results demonstrate that the proposed control strategy can efficaciously enhance the current loop bandwidth of the motor.