Study on six‐phase PMSM control strategy based on improved position sensorless detection technology

The six‐phase motor control system has low torque ripple, low harmonic content, and high reliability; therefore, it is suitable for electric vehicles, aerospace and other applications requiring high power output and reliability. This study presents a superior sensorless control system for a six‐phase permanent magnet synchronous motor (PMSM). The mathematical model of PMSM in stationary coordinate system is presented; its sliding mode observer (SMO) of back electromotive force (BEMF) acquires the motor speed and position information. As torque ripple and harmonic components affect the BEMF estimated value through the traditional SMO, the function of the frequency‐variable tracker of the stator current (FVTSC) is used instead of the traditional switching function. By improving the SMO method, the BEMF is estimated independently, and its precision is maintained under startup or variable‐speed states. To improve performance of the system, the auto disturbance rejection controller (ADRC) is used to suppress load disturbance and speed overshoot. To reduce model parameters, an ADRC with sliding mode algorithm is proposed, simplifying the structure and simultaneously solving the parameter tuning problem. Finally, comparing the ADRC with FVTSC SMO and the traditional PI controller shows that the new ADRC effectively improves the dynamic and static performance of the PMSM.