自起动稀土永磁电机断相运行时步有限元分析

Open-phase operation analysis of line-start rare-earth permanent magnet motor with time-stepping FEM

为了研究自起动稀土永磁电动机断相后的运行特性,建立了断相运行的场—路—运动直接耦合时步有限元模型。以一台22 kW永磁电机为例,分析了其在30%和50%额定负载下断相前后的定子电流、转矩波动及损耗情况。计算结果表明,在负载转矩保持不变的条件下,断相后定子电流接近断相前的2倍,转矩发生大幅度波动,而总损耗分别增加32%和84%。因此,从减小损耗与转矩波动两方面考虑,自起动稀土永磁电机即使轻载工况下也应尽量避免断相运行。实测数据验证了计算结果的正确性。

In order to study the open-phase operation characteristics of line-start rare-earth permanent magnet （ PM ） motors, the field-circuit-motion directly coupled model for open-phase operation was established. Based on this model, the performance of a 22 kW PM motor, such as currents, losses and torque in open-phase condition, was analyzed under 30% and 50% rated load condition. The result shows that, the stator current may be close to two times of the normal one and torque ripples greatly, and furthermore the total losses of those two conditions are increasing by 32% and 84% respectively. Therefore, taking losses and torque ripple into account, the open-phase operation should be avoided as far as possible even though the motor is at light loads. The correctness of numerical result is verified by tested data.