Single-Loop Current-Constrained Speed Regulation for PMSM via a Switching Controller

The single-loop control structure of permanent magnet synchronous motor (PMSM) is widely considered in practical applications. However, certain issues such as overcurrent risks and multisource disturbances may result in unsatisfactory speed regulation performance and increase the risk of damage to the system circuitry. In this article, a current-constrained continuous nonsingular terminal sliding mode control (CNTSMC) approach is proposed to address these problems. First, two finite-time disturbance observers (FTDOs) are designed to estimate both matched and mismatched disturbances in the PMSM systems. Then, a composite CNTSMC method incorporating the disturbance estimation is designed to improve the anti-disturbance ability of PMSM systems. To realize overcurrent protection, a novel switching idea is introduced based on the composite CNTSMC method, which is implemented only when the current reaches the constraint boundary. Finally, the stability analysis of the closed-loop control system is presented, and the proposed method is demonstrated to be effective through experimental tests.