Finite-time control for permanent magnet synchronous motor speed servo system via a disturbance observer

This paper presents the finite-time control problem for permanent magnet synchronous motor (PMSM) speed servo system using different kinds of finite-time control methods. Integral terminal sliding mode controller and continuous finite-time controller are designed respectively for the speed loop and d-axis current loop. The proof of finite-time stability for PMSM speed servo system is also given. Compared with the corresponding control method of asymptotical stability, the controller based on the finite-time control can make the output of system track the desired speed reference signal in finite time and obtain a better dynamic response and anti-disturbance performance. Meanwhile, considering the large chattering phenomenon caused by high switching gains, a composite integral terminal sliding mode control method based on disturbance observer is proposed to reduce chattering. Through feed-forward compensation based on disturbance estimation, the composite integral terminal sliding mode controller may take a smaller value for the switching gain without sacrificing disturbance rejection performance. TMS320F2808 DSP experimental results are provided to show the superiority of the proposed methods.