关键词: 永磁同步电机, 绕组星-角形接法切换策略, 全球统一车辆测试规程, 综合效率

Abstract: The permanent magnet synchronous motor ( PMSM) ,renowned for its high torque density and superior energy efficiency,has emerged as the main motor in electric vehicle propulsion systems. However, PMSM generally requires flux weakening control during operation in the medium and high speed range,sacrificing efficiency and power factor in the high speed range. A dynamic winding star-delta switching strategy is adopted in this paper,to enable PMSM to achieve high starting torque,wide speed range,and efficient operation under all operating conditions. The electromagnetic performance simulation and loss calculation of PMSM are completed using finite element analysis,and the comprehensive efficiency of PMSM with the star-delta dynamic switching strategy is quantitatively evaluated under the worldwide light vehicle test cycle conditions using
the energy method. The research results show that the star-delta switching strategy can integrate the advantages of high torque in star connection and high efficiency in delta connection, and its comprehensive efficiency is improved by about 0. 53% compared to star connection. This paper quantitatively evaluates the impact of different switching speed thresholds on comprehensive efficiency and finds that when the switching speed threshold is set at 5 100 r / min,the motor can achieve both smooth torque transition and efficient operation,effectively expanding the efficient operating range of PMSM.

Key words: permanent magnet synchronous motor, star-delta switching strategy, worldwide light vehicle test cycle, overall efficiency