Research on Improved Feedback Field-weakening Control Strategy of Permanent Magnet Synchronous Motor for Distributed Drive System

The surface-mounted permanent magnet synchronous in-wheel motors for distributed drive electric vehicles are thoroughly studied. Firstly, the motor torque characteristics under high torque level and wide speed range are analyzed. Comparison of the advantages and disadvantages for traditional open-loop flux-weakening strategy and the feedback-based flux-weakening strategy are conducted. Furthermore, an improved feedback flux-weakening control strategy with deep feedforward which is easy to be implemented in engineering is proposed. Both the working principle and the calculation method of feedforward and feedback parameters are elaborated. The stability of the current loop is also analyzed through the derivation of its closed-loop transfer function. Finally, the controlling performance of the proposed method is validated by simulation result. The improved feedback flux-weakening control strategy proposed in this paper has significant advantage in efficiency, torque accuracy and engineering application.