中文摘要：

永磁同步电机转矩中定子磁链幅值和转矩角均为可控变量，直接转矩控制的实现方法不唯一。根据永磁同步电机定子磁链和转矩角均可控的特点提出了一种最优直接转矩控制方法。该方法不要求保持定子磁链幅值恒定，直接以转矩为最终控制目标选择最优电压矢量实现对电机转矩的直接控制，省去了传统直接转矩控制方法中的磁链环。实验结果验证了理论分析的正确性和转矩控制方法的可行性。

英文摘要：

The amplitude of stator flux and torque angle in permanent magnet synchronous motor （PMSM） are controllable, the implementation method of direct torque control in PMSM is not unique. A new torque control method was presented according to the characteristic that the amplitude of stator flux linkage and torque angle are all controllable. The amplitude of the stator flux linkage and the torque angle were controlled synthetically. The optimal voltage vector was selected according to the torque requirement directly and the stator flux linkage control loop in traditional control method was eliminated in the proposed torque control method. The validity of the theory analysis and the feasibility of the toque control method are verified by the experiment results.