考虑磁桥不均匀饱和的内置式永磁同步电机等效磁网络模型

Equivalent Magnetic Network Model for Interior Permanent Magnet Machines Considering Non-Uniform Saturation of Magnetic Bridges

为了提高计算精度,提出了一种可考虑磁桥不均匀饱和的内置式永磁同步电机(IPMSM)改进等效磁网络(EMN)模型。在分析不均匀饱和现象产生机理的基础上,将极间磁桥划分为四个子区域,根据每个子区域的几何结构及其磁力线走向搭建相应的多段非线性磁导单元,以考虑磁桥不均匀饱和及饱和偏移现象。以一台20kW车用IPMSM为例,利用所提出的模型对电机的空载、负载磁场及空载反电动势进行计算,并将计算结果与传统EMN模型、有限元分析及实验结果进行对比。结果表明,相比于传统EMN模型,所提出的改进EMN模型对气隙磁通密度和空载反电动势的计算精度可提高4%以上。最后,分析所提出模型的适用性,结果表明,当磁桥内磁通密度最大值与最小值的比大于约1.3时,磁桥不均匀饱和现象严重,需通过所提出的改进EMN模型来准确计算电机的电磁特性。

In order to improve the calculation accuracy,an improved equivalent magnetic network(EMN)model is proposed for interior permanent magnet synchronous motors(IPMSM)considering the non-uniform saturation of the magnetic bridge.By analyzing the causes of uneven saturation phenomenon,the magnetic bridge is divided into four regions.According to the geometric structure and flux distribution of each region,the nonlinear permeance unit is used to consider the non-uniform saturation and the saturation shift of the magnetic bridge.Then,taking a 20kW IPMSM as an example,the proposed model is used to analyze the no-load and load magnetic fields and no-load back electromotive force(EMF),and the calculated results are compared with the traditional EMN model,finite element analysis(FEA)and experimental results.It is shown that the proposed model can improve the calculation accuracy by more than 4%compared with the traditional EMN model.Finally,the applicability of the proposed model is analyzed.The results show that when the ratio of the maximum to minimum magnetic density in the magnetic bridge is greater than about 1.3,it is necessary to consider the non-uniform saturation of the magnetic bridge by the proposed model.