Robust Backstepping Tracking Controller for Low-Speed PMSM Positioning System: Design, Analysis, and Implementation

This paper is concerned with the design and implementation of a robust position backstepping tracking controller for a permanent magnet synchronous motor (PMSM). The information on the angular position and velocity, provided by a classical resolver-to-digital converter, additionally employs a phase lock loop (PLL) circuit. A backstepping control law is designed from the input-output linearization of the PMSM model, written in d-q coordinates. This controller is adapted via the online estimation of the unknown load torque and friction effects. A linear extended state observer is devised for this purpose, thus ensuring high closed-loop performance of the motor trajectory tracking task. An input-state stability analysis of the entire system is also provided. Cosimulation via the MATLAB/Simulink-PSIM package, including realistic measurement disturbances, is used to investigate the stability and accuracy of the proposed control algorithm. Experimental results are provided.