A Composite Control Strategy for Permanent Magnet Synchronous Motor Drives Based on Improved Integral Sliding Mode Control and Three-Vector Model Predictive Current Control

Abstract

Traditional model predictive current control (MPCC) usually applies only one voltage vector in each control cycle, which limits the voltage-vector regulation capability and may lead to relatively large steady-state current and torque ripple. Although the dual-vector method improves the voltage regulation capability, the coverage range of synthesized voltage vectors is still limited. To overcome these limitations, a three-vector model predictive current control (TV-MPCC) strategy is developed in this paper. The proposed method combines two adjacent active vectors and one zero vector in a single control cycle, and employs deadbeat-based dwell-time calculation and equivalent virtual-voltage-vector synthesis to improve current tracking performance and steady-state current quality of the system. To enhance the robustness of the predictive control system against parameter uncertainties and load disturbances, an Improved Integral Sliding Mode Control (IISMC) strategy is integrated into the speed loop, forming a speed-current dual-loop control framework. The IISMC retains the integral sliding surface and introduces an improved nonlinear variable-gain exponential reaching law and a saturation function to regulate the convergence process and alleviate steady-state chattering. Finally, simulation results demonstrate that the proposed composite control strategy reduces current harmonic distortion and electromagnetic torque ripple, while improving speed-regulation quality and disturbance rejection capability.