混合动力汽车牵引电机永磁体温度建模

Modeling of permanent magnets temperature of traction motors in HEV

建立了两个不同永磁体温度预测模型:模型一是从温度与永磁体性能的关系出发,由实时检测的电压、电流、转速和绕组温度通过运算而求得永磁体温度;模型二是从电机的损耗出发,建立了电机的热路,该热路包含连接点,热阻和热源,体现了整个电机内的热循环过程,求解热路而得到永磁体温度。另外,考虑永磁体涡流损耗,进一步提高计算精确性。在三相正弦电压供电下,对以给定电机进行计算,结果由实验验证。对PWM电源供电的情况下,由于PWM波中含有大量的高次谐波,因此永磁体温升明显。此外,通过有限元仿真进一步验证了本文所提的两种温度预测模型的正确性。

The temperaturerise inside the magnets of interior permanent magnet synchronous motors （IPMSM） in hybrid electric vehicles （HEV） caused by losses can lead to potential irreversible demagneti zation. Two different analytical models of temperature prediction were developed. Based on the relationship of the temperature and the magnets performance, the temperature of magnets was predicted through solving the function of voltage, current, rotate speed and winding temperature in the first model. The other analyti cal model was developed as thermal circuits with network of interconnected nodes, thermal resistances and heat sources representing the heat processes within the IPMSM, to describe the temperature of the magnets. In addition, calculation accuracy was improved due to considering eddy current loss in the magnets. The predicted temperature of two models was validated by experiments as the motors operated by three phase sine supply. When the motor is driven by pulsewidthmodulated （PWM）, the model shows more tempera turerise in the magnets due to the abundant high frequency harmonics of PWM waveform. Furthermore, the finite element analysis （FEA） simulation results give more confidence for the proposed estimators.