螺杆机用并轴双转子永磁电机齿槽力矩机理分析与抑制

Mechanism analysis and suppression of cogging torque in parallel axis dual rotor permanent magnet motors for screw machines

针对并轴双转子永磁电机过大的齿槽力矩以及转矩脉动大等电磁问题,采用传统单个槽齿槽转矩理论以及双转子电机边端力矩波动理论进行分析,计算了并轴双转子电机齿槽力矩的特殊组成成分以及其各部分转矩的谐波阶次。分析改变磁极偏心距和转子斜极对电机齿槽力矩和转矩特性的影响。采用响应面法构建电机的多目标优化模型,通过改变永磁体偏心距和斜极块数来约束电机的优化变量,并采取约束关系以及优化目标求解出最优转子结构参数。构建有限元模型,验证齿槽力矩理论的正确性。对比采用最优转子结构参数下电机的电磁性能与优化前电机的电磁性能,优化后电机的齿槽力矩、转矩脉动等电磁性能进一步提升,验证了采用磁极偏心和转子斜极复合结构的有效性。

In view of the electromagnetic problems such as excessive cogging moment and large torque pulsation of the parallel shaft dual-rotor permanent magnet motor,the traditional theory of single-slot cogging moment and the theory of fluctuation of side-end torque of the dual-rotor motor were analyzed,and the special components of the cogging moment of the parallel shaft dual-rotor motor as well as the harmonic orders of the torque of each part of the cogging moment were calculated.The effects of changing the pole eccentricity and rotor inclined pole on the cogging moment and torque characteristics of the motor were analyzed.The response surface method was used to construct a multi-objective optimization model of the motor,and the optimization variables of the motor were constrained by changing the permanent magnet eccentricity and the number of inclined pole blocks,and the optimal rotor structure parameters were solved through the constraint relationship as well as the optimization objectives.The finite element model was constructed to verify the correctness of the cogging moment theory.Comparing the electromagnetic performance of the motor under the optimal rotor structure parameters with that of the motor before optimization,the electromagnetic performance of the motor after optimization,such as cogging moment and torque pulsation,is further improved,which verifies the validity of adopting the composite structure of pole eccentricity and rotor inclined pole.