中文摘要：

永磁电机中，定位转矩造成振动、噪声以及控制的困难等不利因素，影响了电机性能的提高。给出用于分析具有分数槽极比结构的永磁电机的简单模型，通过解析分析解释消除定位转矩的机理。借助于该模型解析分析由于转子永磁体不对称引起的定位转矩的影响和由于永磁体磁动势幅值和相位误差造成的影响，并进行实验验证，实验结果与分析一致，研究成果对提高无刷流伺服电机的性能和减小定位转矩具有实用意义，并取得了实际效果。

英文摘要：

In the permanent-magnet motor, the cogging torque is rather concerned because it is often a principle source of vibration, noise and control difficulty. The simplified model for analyzing permanent-magnet motor with fractional ratio of slots and poles was presented, and the principle of removing cogging torque was explained clearly by mathematical analysis The influence on cogging torque caused by non-uniform of rotor permanent-magnet can be analyzed by this model. The influence caused by amplitude and position errors of permanent-magnet magnetic motive force was analyzed, which was confirmed by experimental examples. Testing results are matched with analyses. The achievement of the research has utility purpose to improve the performance of brushless DC servomotor and reducing cogging torque. Moreover, practical effects have been got.