电动车用轮毂电机场路耦合分析

针对电路模拟法和电磁解析法难以准确计及铁磁材料磁导率非线性的影响,以及磁场有限元法难以分析外电路为非标准正弦激励等问题,采用场路耦合法分析电动车用轮毂电机特性,将电磁场有限元方程与外电路方程联立求解,充分考虑外电路中时间谐波电流等非线性因素对磁场的影响,实现电磁场量和电气量的直接耦合。推导轮毂电机电磁场与外电路耦合离散方程、机械运动方程以及功率损耗方程,计算其负载感应电动势和功率损耗,对比分析磁场有限元法和场路耦合法计算结果的差异,并研究轮毂电机功率损耗密度的分布规律。分别采用磁场有限元法和场路耦合法计算在不同工况运行时电机的效率特性,通过样机实验对比分析,结果表明:场路耦合法计算结果更准确,证明所用分析方法的正确性。

Field-circuit coupled analysis on in-wheel motor of electric vehicle

Aiming at the fact that the circuit simulation and electromagnetic analysis method is difficult to accurately take into account the magnetic material permeability nonlinearity, and the finite element method is difficult to analyze the external circuit with non-standard sine excitation, we use the field-circuit coupling method to analyze the efficiency of in-wheel motor for electric vehicle, solve the electromagnetic field finite element equation and the external circuit equation together, and consider the influence of nonlinear factors such as time harmonic current on the magnetic field, to realize the direct coupling of the electromagnetic field quantity and the electrical quantity. The coupling equations of the electromagnetic field and the external circuit of the in-wheel motor, the equation of motion and the power loss are derived, and the load induced electromotive force and power loss are calculated, the difference between the finite element method and the field-circuit coupling method is compared, then the distribution of power loss density is studied. The efficiency characteristics of the motor under different working conditions are calculated by finite element method and the field-circuit coupling method respectively, and the results show that the field-circuit coupling method is more accurate and the correctness of the analysis method is proved.