计及磁饱和的车用永磁同步电机MTPA控制技术

永磁同步电机具有较高的效率和功率密度,在电动汽车驱动系统中广泛应用。电机的d、q轴电感是设计控制系统的重要参数,但重载情况下受磁饱和及交叉饱和影响严重。传统控制技术忽略磁饱和效应,导致转矩控制的精确性不足。采用有限元法分析电机负载时的磁饱和情况,计算考虑磁饱和及交叉饱和的d、q轴电感参数。以此为基础,拟合d、q轴电感和电流关系。设计计及磁饱和的最大转矩电流比MTPA(maximum torque per ampere)控制,使d、q轴参考电流计算中使用的电感随电机电流变化。通过对比,证明计及磁饱和的MTPA控制能够实现输出转矩的精确控制,提高永磁同步电机的动态响应性能。

MTPA Control Technology of Permanent Magnet Synchronous Motor Used in Electric Vehicle Considering Magnetic Saturation

Permanent magnet synchronous motor with high efficiency and power density is widely used in drive system of Electric Vehicle. D-q axis inductance of the motor is important in the design of a control system, but they are severely affected by magnetic saturation and cross-coupling in over-load situation. Traditional MTPA control ignores the effect of magnetic saturation and cross-coupling and therefore to decrease the con-trol accuracy of output torque. This paper calculated d-q axis inductance considering magnetic saturation and cross-coupling by finite element analysis (FEA). Based on this, the relationship between d-q axis inductance and current is fitted. MTPA control considering magnetic saturation is designed. The modified make the inductance changed with the motor current when calculate the reference current. By comparison, this paper prove the MTPA control considering magnetic saturation can achieve accurate control of output torque and can improve dynamic response of motor.