直流无刷电机中齿槽转矩的能量分析

Energy Analysis of Cogging Torque in Brushless DC Motor

齿槽转矩是齿槽类无刷永磁电机的固有指标,在定子绕组断电状态下,由永磁体的永磁场与定子铁心的齿槽结构相互作用形成电磁力,进而在圆周方向产生周期性的固定转矩。本文从能量守恒的角度出发,根据齿槽转矩的产生机理推导出齿槽转矩与电磁结构的公式关系,以3对极和6对极两款直流无刷电机为例,利用二维有限元法分析了齿槽转矩在圆周方向的能量分布,研究表明,相同槽数的电机在一个周期内符合能量守恒定律,极对数的不同会造成齿槽转矩不同,通过选择合理的方法能够有效的利用齿槽转矩达到电机断电制动的效果。

Cogging torque is an inherent index of toothless permanent magnet motor.In the case of stator winding power-off,electromagnetic force is formed by the interaction between permanent magnetic field of permanent magnet and cogging structure of stator core,and then periodic fixed torque is generated in the circumferential direction.From the point of energy conservation,this paper deduced the formula relationship between cogging torque and electromagnetic structure according to the generating mechanism of cogging torque.Taking 3 pair pole and 6 pair pole DC BLDCM as an example,the energy distribution of cogging torque in the circular direction was analyzed by using two-dimensional finite element method.The research shows that the motor with the same number of slots conforms to the law of energy conservation in one cycle,and the logarithm of poles.The difference of the gear groove torque will cause different,and the effective use of cogging torque can be achieved by selecting a reasonable method to achieve the effect of motor power off braking.