定子无铁心轴向磁场永磁轮毂电机损耗分析及效率优化

Loss Analysis and Efficiency Optimization of Ironless Stator Axial Flux Permanent Magnet In-wheel Machine

减速装置的引入使得轮毂电机分布式驱动系统对电机本体的效率提出了更高的要求。为了实现定子无铁心轴向磁场永磁轮毂电机在其常用工况下的高效率,该文分析了利兹线和扁线对定子槽满率的影响规律,建立了不同线型绕组的交流损耗计算模型,对不同线型绕组电机的交直流铜损进行了计算与对比分析,并基于损耗产生机理提出扁线绕组分股和换位的交流损耗抑制方法。在此基础上,针对轮毂电机驱动系统的常用工况,对不同线型绕组电机的损耗和效率进行全面对比。结果表明,采用该文提出的效率优化方法可以实现扁线绕组的低损耗及电机的高效率,使用改进型扁线绕组的定子无铁心轴向磁场永磁电机适合作为减速驱动轮毂电机应用,尤其是对转矩需求较高的轮毂电机。试验结果验证了理论和仿真分析方法的正确性。

The implementation of gear reducer in the distributed in-wheel-drive system requires much higher efficiency from the traction motor itself. In order to realize high efficiency of the ironless stator axial flux permanent magnet(AFPM) in-wheel machine in its common working conditions, this paper analyzed the influence of the Litz wire and the flat wire on copper filling ratio, and established the ac loss calculation model of different wire types. The calculation and comparative analysis of the AC and DC copper losses of machines with different wire types were carried out. Based on the mechanism of loss, a method of division and transposition in flat wire winding was proposed to restrain the AC loss for this type machine. On the basis, the loss and efficiency of different wire types for the common working conditions of in-wheel machine were compared comprehensively. The results show that the efficiency optimization method proposed in this paper can achieve low loss of the flat wire winding and high efficiency of the machine. The ironless stator AFPM machine using the improved flat wire winding is suitable as an in-wheel machine, especially in-wheel machine with high torque requirement. The experimental results verify the correctness of the theory and simulation analysis method.