The magnetic circuit feature of a radial–axial brushless hybrid excitation machine (RA-BHEM) is studied in this article. An axial stator is placed on one side of the rotor, which is wound with ac excitation winding to adjust the air-gap flux flexibly to make it have good flux regulation capability. The flux distribution of the RA-BHEM is a radial–axial 3-D mixed magnetic circuit, which is difficult to be analyzed by the 2-D finite-element analysis (FEA). Therefore, a radial–axial equivalent magnetic circuit (RAEMC) model is established to obtain the air-gap flux density with different excitation magnetomotive forces (MMFs), which simplifies the design process and reduces the amount of calculation. The flux density distribution in different MMFs is analyzed by 3-D finite FEA and the results are consistent with the RAEMC model results. The torque characteristics in the low-speed region and the flux-weakening capability in the high-speed region are analyzed to verify the possibility of the proposed machine in the field of electric vehicles (EVs). Finally, a 2-kW prototype is manufactured to verify the correctness of the above analysis.

中文翻译：

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电动汽车径向-轴向无刷混合励磁机磁路特性研究


本文研究了径向-轴向无刷混合励磁机（RA-BHEM）的磁路特性。转子一侧放置轴向定子，定子上绕有交流励磁绕组，可灵活调节气隙磁通，使其具有良好的磁通调节能力。 RA-BHEM 的磁通分布是径向-轴向 3 维混合磁路，很难通过 2 维有限元分析 (FEA) 进行分析。因此，建立径向轴向等效磁路（RAEMC）模型来获得不同励磁磁动势（MMF）下的气隙磁通密度，简化了设计过程并减少了计算量。通过3-D有限元分析对不同MMF中的磁通密度分布进行分析，结果与RAEMC模型结果一致。分析了低速区域的扭矩特性和高速区域的弱磁能力，以验证所提出的机器在电动汽车（EV）领域的可能性。最后制作了一台2kW样机来验证上述分析的正确性。