3对极无轴承交替极薄片电机的理论与实现

Theory and Realization of 3 Pole Pairs Consequent-pole Bearingless Slice Motor

无轴承交替极永磁电机因其悬浮与旋转本质上完全解耦,其控制系统得以极大简化,但其前提条件是电机极对数必须≥4。极对数过大限制了其应用范围,特别是在高速场合。为减少极对数,该文研究了一种3对极无轴承交替极永磁电机。通过磁路分析发现,3对极电机中存在一固有的悬浮力脉动,且该悬浮力脉动无法完全消除。分析该脉动的数学模型发现,通过适当增加永磁体厚度、减小气隙的方法,可以将悬浮力脉动控制在可接受的范围内,采用有限元仿真对该结论进行了验证。通过实验,实现了3对极原理样机的稳定悬浮,证明了3对极无轴承交替极永磁电机的可行性。

The levitation of the consequent-pole bearingless PM motor is decoupled with the rotation, so the control system is simplified dramatically. However, that the motor pole pair number is lager than 3 is required. And the great pole number limits the application of the motor, especially in the high speed field. To reduce the pole number, the 3 pole pairs consequent-pole bearingless PM motor is studied. The magnetic circuit analysis shows that an inherent suspension force pulse exits in the 3 pole pairs motor which can＇t be eliminated completely. And it can be derived that the pulse can be suppressed to an acceptable range by thickening the permanent magnet and shortening the gap length properly. The conclusion is verified by finite element simulations. Finally, a prototype is built and the stable suspension is achieved which prove the feasibility of 3 pole pair consequent-pole bearingless slice PM motor.