中文摘要：

提出了用于永磁电机中棱柱形永磁体模型的等效方法，即改进磁偶极子模型，详细推导了改进磁偶极子模型中参数的确定和优化过程，包括模型中约束条件、目标函数及检验条件的建立。文末以自起动永磁同步电机作为算例，通过有限元仿真方法，得到了永磁电机指定路径上的电磁场分布结果，并与用Matlab仿真算法实现的改进磁偶极子模型模拟的永磁电机电磁场分析结果进行了对比，验证了该方法的有效性和合理性。

英文摘要：

The paper presented an equivalent model which was named improved magnetic dipole model using to analyze box permanent magnet electromagnetic field in permanent synchronous motor. And the paper analyzed the process of parameters acquirement and optimization in detail, which included the establishment of constraint conditions, objective function and verification＂ condition. At last, the paper took a line start-per- manent magnet synchronous motor （LSPMSM） as an example and got electromagnetic field distribution of the particular path using finitelement method. At the same time, the paper got the equivalent model of the permanent magnet of LSPMSM by using Matlab software, and got the magnetic flux density B of several repre- sentative points in the particular path. By comparing the two kinds of results, the paper verified the correctness of improved magnetic dipole model.