Data-Driven-Model-Based Full-Region Optimal Mapping Method of Permanent Magnet Synchronous Motors in Wide Temperature Range

Abstract

To improve the motor efficiency and expand the actual external characteristic region of electric vehicle permanent magnet synchronous motor (PMSM) drive systems, the optimal operation of mapping torque to d-q axis current is usually applied. Nevertheless, it is difficult to deal with the complex mechanism factors such as parameter saturation and temperature change for the traditional optimization method based on the basic voltage equation of PMSM. In this paper, a black-box-model-based torque–current optimization method is proposed, which does not rely on any information of the inner mechanism model, and the derivative-free, optimal, improved Nelder–Mead Simplex(NMS) method is used to minimize the copper loss and maximize the electromagnetic torque in the flux-weakening region. Moreover, a synchronous online compensation of the electromagnetic torque and optimal current angle is implemented, in view of the time variation of permanent magnet flux with temperature. Finally, through a comparison experiment with the nominal-parameters-based formula maximum torque per ampere (MTPA) method, the proposed method achieves higher torque accuracy and better efficiency performance in a wide temperature range with regard to a reasonable response speed.