Continuous-Control-Set Model-Free Predictive Fundamental Current Control for PMSM System

Abstract

Although the robustness is enhanced essentially by the model-free predictive control, the accuracy of its data-driven model is directly affected by the unnecessary current harmonics, such as the harmonics caused by the control strategy itself. To reduce the influences of these harmonics, a continuous-control-set (CCS) model-free predictive fundamental current control (MF-PFCC) strategy is proposed in this paper for the permanent magnet synchronous motor (PMSM) driving system. Harmonics due to the controller including side frequency effect and frequency coupling effect are analyzed in principle, and a frequency-converting double second-order generalized integrator (DSOGI) structure is designed to exclude the fundamental terms from the sampled current to cut the coupling path of the effects and to improve the accuracy of the data-driven model in the MF-PFCC without any time-variable physical parameters. The analyses of the effects and the effectiveness of the proposed method are verified by experimental and supplementary simulation results, as well as advantages including the reduced influence of effects and enhanced robustness with improved stator current quality.