Abstract: The load torque disturbance and the change in moment of inertia will affect the control of permanent magnet synchronous motor(PMSM). In order to improve the response speed and anti-interference ability of the system and reduce the influence of load disturbance on the control performance, the observed load torque feed forward is compensated into the torque current, and the exponential reaching rate function in the sliding mode speed controller is improved. An improved disturbance observer is designed, in which a variable gain algorithm is added to the traditional disturbance observer. In order to solve the problem of the change of inertia caused by load disturbance, it combined with the model reference adaptive algorithm, and the identified inertia is updated to the improved disturbance observer and sliding mode speed controller. The simulation results show that the improved disturbance observer can accurately observe the load torque, effectively reduce the system chattering, and improve the disturbance rejection ability and dynamic response performance of the control system.

    Key words: permanent magnet synchronous motor; disturbance observer; feed forward compensation; variable gain algorithm; moment of inertia identification