考虑交叉耦合时电动汽车用内置式永磁同步电机交直轴电感计算

内置式永磁同步电机(IPMSM)以高转矩电流比、更宽的调速区间、高功率密度、高效率等优点在电动汽车领域应用广泛。电动汽车用IPMSM磁路结构复杂,饱和程度高,造成交直轴磁路的交叉耦合,使得交直轴之间产生互感。对交叉耦合现象进行了磁路分析,阐述了其对磁链和电感参数的影响。采用冻结磁导率法(FPM)和有限元法(FEM)对交直轴电感进行计算,并对电感参数随电流变化情况进行了定量分析。对比2种计算方法得出的交直轴电感参数,发现计算结果吻合较好。最后,对比分析了2种方法计算交直轴电感的优缺点,分析表明以FEM为主FPM为辅计算交直轴电感参数,能保证电感参数的精确度,缩短计算时间。

Calculation of Quadrature- and Direct-Axis Inductances of Interior Permanent Magnet Synchronous Motor for Electric Vehicles Considering Cross Coupling

Interior permanent magnet synchronous motor (IPMSM) is widely used in the electric vehicle field due to its high torque-to-current ratio, wider speed regulation range, high power density, and high efficiency. IPMSM for electric vehicles has a complicated magnetic circuit structure and a high degree of saturation, causing the cross coupling between the magnetic circuits of quadrature- and direct-axis. Therefore, mutual inductance is generated between quadrature and direct axis. Magnetic circuits analysis is carried out for the cross-coupling phenomenon, and the influences of cross coupling on the magnetic flux linkage and inductance parameters are elaborated. The frozen permeability method (FPM) and the finite element method (FEM) are used to calculate the quadrature- and direct-axis inductances, and the changes of inductance parameters with current are quantitatively analyzed. The two calculation methods are compared, and it is found that the calculation results agree well with each other. The advantages and disadvantages of the two methods for calculating the quadrature- and direct-axis inductance are analyzed. The analysis shows that using FEM as the main means and FPM as the auxiliary to calculate the quadrature- and direct-axis inductance parameters, the accuracy of the inductance parameters can be ensured and the calculation time can be shortened.