A Stator Current Oriented Closed-Loop $I\text{--} f$ Control of Sensorless SPMSM With Fully Unknown Parameters for Reverse Rotation Prevention

For the defects of speed oscillation, fixed current amplitude and inclined to lose synchronism in open-loop I - f control approach, a new stator current vector oriented closed-loop I - f control scenario is proposed for surface-mounted permanent magnet synchronous motor (SPMSM) with fully unknown parameters. In a stator current vector oriented coordinate system d*q*o, the dynamic model of SPMSM is established. Based on analysis of control performance for conventional open-loop I - f control, the control framework of closed-loop I - f control is presented and closed-loop regulators of angle, speed, and current are derived. Additionally, the adaptation law estimating totally unknown parameters of SPMSM is simultaneously accomplished in the design of controller and avoids construction of estimation algorithm separately. The stability of the controller is proved in the sense of Lyapunov theory. The validity of the proposed algorithm is verified through both simulations and hardware experiments. The results indicate that the improved control scheme ensures the speed to track the expected value rapidly and stably in different load conditions, and the current amplitude is regulated to enlarge with the increasing of load torque automatically. Furthermore, fully unknown parameters are estimated precisely and reverse rotation of motor at startup enables to be prevented effectively.