A Robust Double Closed-Loop Control Scheme for PMLSM Drives

In this paper, a novel velocity and current double closed-loop control scheme applied to the permanent magnet linear synchronous motor (PMLSM) drives is proposed, and to suppress various uncertainties and disturbances, the advanced observation technique is introduced. First, as the inner loop, the current loop adopts the predictive current control method, which can increase the current control bandwidth and tracking precision. To improve the dynamic response and robustness of the velocity loop, a super-twisting sliding-mode control strategy is presented. Second, to overcome the parameter mismatch issue in the current loop and suppress different force disturbances in the velocity loop, their respective super-twisting sliding-mode observers are structured, and the corresponding estimated values are injected into the double closed loops by the feedforward method. At last, based on the precise PMLSM testing platform, the experimental studies are carried out to prove the effectiveness and correctness of the proposed scheme.