高频轴向磁通永磁电机永磁体涡流损耗三维解析模型

Three-dimensional Analytical Model of Eddy Current Loss of Permanent Magnet in High Frequency Axial Flux Permanent Magnet Machine

针对现有二维解析模型在计算轴向磁通永磁电机永磁体涡流损耗存在精度不足的问题,该文提出一种能够精确计算该类电机永磁体涡流损耗的新型三维解析模型。该模型利用精确子域法和电阻网络模型,能够同时考虑定子开槽、定子谐波电流、涡流反作用和涡流三维分布的影响。利用有限元法验证了精确子域模型计算得到的空载和电枢磁场分布,并在理想空载下,验证了解析模型永磁体表面涡流密度和永磁体涡流损耗值,分析电机在高频运行下涡流反作用对永磁体涡流损耗的影响。最后,对1台7kW、4000rpm的轴向磁通永磁电机进行空载脉宽调制(pulsewidthmodulated,PWM)电压供电实验和空载正弦波电压供电实验,得到因PWM谐波电流引起的永磁体涡流损耗,将实验结果,有限元结果与解析结果作对比,验证了该解析模型的正确性。

To solve the problem that the existing two-dimensional analytical model has insufficient accuracy in calculating the eddy current loss of permanent magnets(PMs) in axial flux PM machines, a new three-dimensional analytical model which can accurately calculate the eddy current loss of PMs of this kind of machine is proposed in this paper. By using the accurate subdomain method and the resistance network model, the stator slotting, stator harmonic current, eddy current reaction and eddy current three-dimensional distribution can be considered simultaneously. The distribution of no-load and armature magnetic field calculated by the accurate subdomain model is verified by the finite element method, and the surface eddy current density and eddy current loss of the PM calculated by the analytical model are verified under the ideal no-load condition. The influence of eddy current reaction on the eddy current loss of PM under high frequency operation is analyzed. Finally, a 7 kW, 4000 rpm axial flux PM machine was tested for no-load pulse width modulated(PWM) power supply and no-load sinusoidal wave power supply. The eddy current loss of PMs caused by PWM harmonic current was obtained. The experimental results and finite element results were compared with the analytical results to verify the correctness of the analytical model.