Single Current Sampling & Double Current Update Method for Current Control of Permanent Magnet Synchronous Motor

Due to the existence of the control cycle in a motor digital control system, the voltage calculated by the current regulator cannot be applied to the motor accurately and timely, which constraints the bandwidth of the current-loop system and influences the dynamic response of the system. To solve this problem, a current reconstruction method during the PWM sampling period in current-loop of permanent magnet synchronous motor is proposed. Firstly, the timing sequence of traditional current sampling and duty cycle update is improved. In one carrier cycle, the current sampling value and the current reference value are used to reconstruct the current and update the duty cycle twice. Secondly, the increment factor is introduced, and the corresponding parameter selection rules are given. By adjusting the increment factor, the current response is improved. Finally, the control system of PMSM is built in Matlab/Simulink, to verify the effectiveness of the proposed current reconstruction method. The simulation results validate the bandwidth of the current-loop is increased with the proposed method.