内置式永磁电机齿槽转矩削弱方法研究

为抑制永磁同步电机齿槽转矩，减少电机振动与噪声，提出一种定子齿顶开辅助槽与转子外圆偏心的结构来抑制齿槽转矩，提升电机的输出性能.首先建立了定子齿顶开槽前后与主气隙分布函数解析式，分析定子开槽与电机主磁场分布及齿槽转矩的关系，同时分析了转子外圆偏心后对齿槽转矩的影响.以内置3相8极48槽V型永磁同步电机为例，利用有限元法对定子齿顶辅助槽个数、槽宽、槽深、槽位置以及转子外圆偏心距等参数进行优化对比分析，获得最优的参数匹配.结果表明：定子齿顶双矩形对称开槽以及转子外圆偏心的方式能有效改善主气隙磁场分布，抑制电机齿槽转矩，优化后的电机气隙磁密5、11、15、17谐波幅值下降明显，电机齿槽转矩峰值降低了59.6％，反电势波形正弦性增强，平均转矩提升，电机输出性能明显改善.

Weakening cogging torque of built-in permanent magnet synchronous motor

A structure of stator tooth jacking auxiliary slot and rotor outer circle eccentricity was proposed for Permanent Magnet Synchronous Motor (PMSM) to suppress the cogging torque and reduce the vibration and noise of motor thus improve the output performance of PMSM.The analytical formula of distribution function was established for the stator tooth top (before and after slotting) and the main air gap, thus clarified the relationships between the stator slotting and the main magnetic field distribution as well as the cogging torque.At the same time, the influence of the rotor outer circle eccentricity on the cogging torque was analyzed.The optimal parameter matching was obtained through optimization tests and comparative analysis of auxiliary slot parameters including slot number, width, depth, slot spacing and rotor outer circle eccentricity, via finite element method on a built-in 3-phase 8-pole 48-slot V-type PMSM.The results showed that the double rectangular symmetrical slotting on the stator tooth top and the eccentricity of the rotor outer circle can effectively improve the magnetic field distribution of the main air gap and restrain the cogging torque of the motor.The harmonic amplitude of the optimized air gap magnetic density 5, 11, 15 and 17 was decreased significantly, the peak value of the cogging torque of the motor was decreased by 59.6%, and the sine of the back EMF waveform as well as the average torque was increased, thus the motor''s output performance was significantly improved.