A Composite Sliding Mode Control for SPMSM Drives Based on a New Hybrid Reaching Law With Disturbance Compensation

This article presents a composite sliding mode control (CSMC) method for speed control of surface-mounted permanent magnet synchronous motors (SPMSMs). The proposed CSMC consists of a new sliding mode control (SMC) based on a novel hybrid reaching law (HRL) and an extended sliding mode disturbance observer (ESMDO). The new HRL is composed of two parts: a terminal reaching part and an exponential plus proportional reaching part. It can effectively suppress the chattering and reduce the reaching time compared with the conventional constant plus proportional rate reaching law (CPRL). The ESMDO is designed based on CPRL. It can estimate the extra chattering produced by the drive system's lumped disturbance and compensate for the controller's output. Based on the proposed new SMC and ESMDO, an antidisturbance sliding mode speed controller is designed to improve the performance of SPMSM drive systems. The performance of the proposed method has been validated experimentally and compared with the CPRL-based SMC methods under different conditions.