混合磁极式永磁同步电机最小有限元求解区域分析

Analysis of minimum finite element solution domain for permanent magnet synchronous machine with hybrid poles

混合磁极式永磁同步电机具有结构简单、无附加气隙,以及调磁方便等优点。根据混合磁极式转子铁磁磁极和永磁磁极2种常见排列方式,给出了其转子磁导和磁动势的表达式,分析了其谐波含量。以混合磁极式分数槽绕组电机为例,从气隙磁通密度的角度,得出了其定、转子侧符合周期性和半周期性的条件,推导并分析了定、转子侧气隙磁通密度谐波次数特点,得到了定、转子侧气隙磁通密度的最小正周期,以及分别以磁极数表示的单元电机,则两者的最小公倍数即为该电机电磁场的最小求解区域。针对混合磁极式永磁同步发电机的电感参数、铁芯损耗、转矩和电压波形进行了计算,通过对整个电机和最小求解区域的计算结果对比,验证了理论分析的正确性。研制了2台混合磁极式永磁同步电机样机,样机的电压波形计算结果与实验结果基本一致。该方法可以准确得到混合磁极式永磁同步电机的最小求解区域,从而大大减小电磁场的计算时间。

The permanent magnet(PM)synchronous machine with hybrid poles has the advantages of simple structure,no additional air gap and easy magnetic field adjustment.According to the two common arrangements of the ferromagnetic poles and the permanent magnetic poles,the expressions of the rotor magnetic permeability and the magnetomotive force(MMF)were given,and the harmonic content were analyzed.Taking fractional slot winding machine with hybrid poles as an example,the conditions for the periodicity and semi-periodicity of the stator and rotor sides were obtained from the perspective of air gap magnetic flux density,and the harmonic characteristics of stator and rotor air gap magnetic flux density were deduced and analyzed.The minimum positive period of the stator and rotor air gap magnetic flux density and the unit machines of the stator and the rotor side expressed by the number of the magnetic pole were obtained respectively.And therefore the common multiple of the unit machines of the stator and the rotor side is the minimum solution area of the electromagnetic field.The inductance parameters,core loss,torque and voltage waveform of PM synchronous generators with hybrid poles were calculated,which verifies the correctness of the theoretical analysis by comparing the calculation results of solving the whole machine and the minimum region.In addition,two prototypes were manufactured,and the calculated voltage waveform were in good agreement with the experimental results.The method can accurately obtain the minimum solution area of the permanent magnet synchronous machine with hybrid poles,and greatly reduce the calculation time of the electromagnetic field.