永磁电机动态退磁的时步有限元计算

Time-stepping finite element computation for dynamic demagnetization of permanent magnet motorr

针对永磁电机瞬态运行时可能出现永磁(PM)材料不可逆退磁的问题,提出了一种利用PM实际磁化曲线建立其非线性退磁模型的永磁电机瞬态运行仿真的时步有限元方法.在电机磁场方程的求解中,给出了适用于各向异性材料的任何单元类型和任何单元个数的雅克比矩阵表示方法,并推导了以空间矢量矩阵表示的牛顿-拉斐逊公式和能实现非线性迭代计算的时步有限元公式.利用该时步有限元方法对一台永磁电机一相突然短路的动态过程进行了仿真计算,计算结果正确显示了PM材料的动态退磁过程.

In order to solve the problem that the irreversible demagnetization of permanent magnet （PM） materials may appear during the transient operation of PM motor, a time-stepping finite element method （FEM） for the transient operation simulation of PM motor was proposed through using the PM actual magnetization curves to establish the nonlinear demagnetization model. In the solving process for the magnetic field equation of PM motor, the Jacobian matrix expression applicable to any type and number of elements for the anisotropy material was given. In addition, the Newton-Rafferson formula expressed by space vector matrix and time-stepping finite element formula which could realize the nonlinear iteration computation were derived. The dynamic process of a PM motor when one phase was suddenly short-circui- ted was simulated with the proposed time-stepping FEM. The computational results correctly show the dy- namic demagnetization process of PM materials.