磁通可控永磁同步电动机的磁化

Magnetization of a Controllable Flux Permanent Magnet Synchronous Motor

提出一种调速机理异于常规永磁同步电动机的新型电动机——可控磁通永磁同步电动机。在需要调速时,通过定子绕组施加一定强度的直轴电流脉冲对磁体进行去磁或充磁,在正常运行时采用id=0的控制策略,而独特的转子结构保证交轴磁动势不对磁体的磁化状态产生影响。由于确定磁体磁化后的最终状态是调磁变速分析的关键,本文建立了包括初始磁化和反复磁化两种情况下的磁化分析模型,扩展了现有的磁化比率曲线。将局部磁滞回线预测模型与磁体的磁化模型相结合,建立了永磁体的磁化状态计算方法。依据该计算模型,计算了不同磁化电流下的气隙磁通密度及相应的电动势波形。样机的实验结果与有限元计算结果较为吻合,证明了该电动机实现磁通可调的可行性和磁化模型的正确性。

The paper proposes a novel permanent magnet synchronous motor with controllable flux. The unique rotor structure makes the performance of magnets could be changed by d-axis current pulse. At the same time, q-axis magnetic motive force, produced by load current, could not influence the statement of magnets. To the analysis of magnetization process of permanent magnets, the paper builds a magnetization model including initial magnetization and repeated magnetization in which magnetization ratio curve is expended. Then combine magnetization model and local magnetic hysteresis loops into determining the state of magnet. On the basis of the model, the paper computes magnetization magnetic field and EMF by finite element method. Prototype test results are consistent with those by finite element method, showing the effectiveness in flux weakening and applicability of the magnetization models.