Nonlinear internal model based two-step controller design for PMSM position servo system

Much recently, a local position tracking and nonlinear disturbance rejection problem of permanent magnet synchronous motor was studied by nonlinear internal model design. This paper generalizes such control problem to the position tracking and nonlinear disturbance rejection problem with wide position range. A two-step controller design strategy is proposed, which is composed of classical triple-loop control and nonlinear internal model control. Note that the proposed two-step controller design strategy can not only achieve exact position tracking with wide position range, but also reject small nonlinear disturbances in the load torque, which can be generated by a so-called nonlinear exosystem. Moreover, it allows certain robustness to the motor parameters. Simulation results are given to verify the effectiveness of our design.