考虑定子外壳漏磁的同极式永磁偏置径向磁轴承磁路模型

同极式永磁偏置径向磁轴承的永磁偏置磁场在定子外壳内形成较大漏磁,而且外壳的有效面积相对工作气隙较大,即使在铁心与外壳间加入隔磁层的情况下,漏磁仍不可忽略,必须进行准确计算。首先直接求解拉普拉斯方程获得隔磁层内的磁场分布,并结合保角变换计算漏磁区域的端部效应,然后求解工作气隙的永磁偏置磁场和电励磁控制磁场,最后建立完整磁路模型和电磁力解析模型。三维有限元仿真结果表明,所建立的磁路模型能准确计算磁轴承工作范围的电磁参数。依据飞轮储能系统的总体需求,设计了径向磁轴承系统,实验结果验证了所建立解析模型和有限元模型的准确性。

Leakage Magnetic Field and Precise Magnetic Circuit Model of the Permanent Magnetic Biased Radial Magnetic Bearing

The stator core of the classical permanent magnetic biased radial magnetic bearing(PMRMB)could produce magnetic flux leakage with the shell easily.Because of the larger area compared with air-gap in this location,the leakage magnetic field can't be ignored even there is magnetism-insulator embedded in it.The paper get the flux density distribution in the stator and the shell with the Laplace equation,then the conformal transform method is applied to obtain the flux density distribution in the air-gap generated by permanent magnet and electro-magnet,the complete magnetic circuit model is established.The proposed magnetic circuit model proved to be effective to calculate the electromagnetic parameters in operation range by 3D finite element analyses(FEA).The PRMB is designed based on the demand of the flywheel energy storage system.A prototype PRMB is manufactured with its control system,and the effectiveness of the proposed magnetic circuit model and 3D FEA is validated by the test results.