基于混合方法的PWM逆变器下永磁同步电动机的温升研究

Temperature Analysis Considering Carrier Harmonics of PMSM by a Hybrid Method

提出一种新型基于等效热网络与有限元相结合的混合方法,建立了三维磁热耦合模型,对一台在脉宽调制(PWM)逆变器驱动下的30 kW/50 Hz表贴式永磁同步电动机进行了仿真研究。首先用场路紧密耦合方法分析电机的分布热源,包括涡流损耗、铁损和铜损。利用该热源分布,结合适当的热网络,研究了耦合温升问题。仿真结果表明,由于载波谐波的影响导致永磁体中涡流损耗的大量增加,其温升也非常显著。试验验证表明,磁块表面和机壳的测量温度与分析结果相吻合,因此该分析方法能准确预测永磁体温度。

A hybrid method of heat network and FEM is proposed to predict the magnet temperature on the 3D magnetic-thermal coupled model of a 30 kW/50 Hz surface PMSM driven by a PWM inverter. The distributed heat source is first calculated by a tight coupled field-circuit method, including eddy current loss, iron loss and copper loss. Using the loss distribution, the coupled thermal analysis is implemented together with the proper thermal circuit. Simulation results indicate that temperature rise in magnets becomes substantially large owing to a high-level increase of eddy current loss due to the influence of carrier harmonics. The measured temperature on the magnet surface is in good agreement with the analyzed one ; as a result, it is clear that the proposed method could get a satisfactory accuracy in stimulating the magnet temperature.