Discrete-time sliding mode controller based on backstepping disturbance compensation for robust current control of PMSM drives

A robust current control approach with disturbance cross-coupling compensation for permanent magnet synchronous motor drives (PMSM) is proposed in this paper. The proposed approach can enhance the reference tracking and provides a robust option for current control of PMSM drives. A discrete-time sliding mode current controller is proposed. The PMSM model includes the digital implementation delay, present due to the discrete-time algorithm execution. A discrete-time backstepping disturbance observer is developed, being combined to the sliding mode controller as a means to improve the robustness and tracking capability. The effects of coupling, parametric uncertainties and load disturbances are compensated by the backstepping disturbance observer. The stability analysis of the combined system is presented and the limits for overall system stability are discussed. Simulations and experimental results validate the combined scheme and demonstrate the good performance of the proposal.