An Improved Torque Enhancement Strategy for Dual Three-Phase PMSM Based on Model-Free Predictive Current Control

As a distinctive feature of dual three-phase permanent magnet synchronous motors (DTP-PMSMs), the method of injecting specific currents in the harmonic plane to boost the output torque has been widely used in applications with high torque requirements. To achieve the desired torque enhancement, precise and prompt tracking of reference harmonic currents becomes essential. However, the harmonic plane of DTP-PMSMs is sensitive to various disturbances, especially the mismatch of the back EMF under load conditions, leading to a deterioration of the control performance of conventional control strategies. In this paper, a model-free predictive harmonic current control (MFPHCC) method based on an extended state observer (ESO) is proposed for the harmonic subspace of DTP-PMSMs. The method can accurately track the harmonic injection reference in the x - y subspace to improve the torque capability under the parameter mismatch condition, and exhibits excellent anti-disturbance capability and robustness. The experimental results demonstrate the superiority and effectiveness of the proposed method.