High-precision control for a surface-mounted permanent magnet synchronous motor based on inverse system approach

This paper addressed the problem of coupling in a surface-mounted permanent magnet synchronous motor (PMSM), and presented a decoupling control approach based on inverse system. Cascading the inversion with original system, the highly nonlinear, multivariable and strongly coupled system was decoupled into two independent pseudolinear subsystems, or an angular speed subsystem and a d-axis stator current subsystem. Then, a hybrid control scheme that combined the sliding-mode control approach and the internal-model principle was proposed with space vector modulation (SVM) technique. With this novel configuration, a time-varying sliding mode controller (SMC) with an integral term, and a classical 2-degree-of-freedom internal-model controller (2-DOF IMC) were adopted in the decoupled angular speed subsystem and the d-axis stator current subsystem, respectively. Ultimately, the proposed scheme was implemented by an established experimental system with low computational demand and high accuracy. Comparative experiments were presented to demonstrate the validity and effectiveness of the proposed control scheme.