基于Maxwell的电动汽车轮毂电机电磁损耗特性分析

电动汽车轮毂电机经常要在复杂的运行工况和恶劣环境下运行,导致轮毂电机电流和内部电磁损耗不断发生变化,对电机温升分析和可靠运行产生严重影响。以1台4 kW轮毂电机为例,利用Maxwell电磁有限元分析软件,建立轮毂电机的电磁有限元模型并对电磁场进行计算。通过选取加速和过载中常见的8种工况进行计算,分析了轮毂电机各部件的电磁损耗分布状态和数值变化规律。由分析结果可知,定子铁耗随转速的上升而增加,随过载倍数增加的变化不大；转子产生的铁心损耗可以忽略不计；永磁体涡流损耗同时随着加速和过载的增加而增加,但加速工况产生的影响更强；绕组铜耗主要受过载倍数变化的影响,占总损耗的比重最大,是主要热源。研究结果为轮毂电机温度场的分析和冷却结构的设计提供重要的参考依据。

Analysis of Electromagnetic Loss Characteristics of Electric VehicleInWheel Motor Based on Maxwell

Electric vehicle inwheel motor often operated in complex operating conditions and harsh environments, resulting in constant changes of the current and internal electromagnetic losses of inwheel motor. The serious impact on the motor temperature rise analysis and reliable operation had happened. Taking a 4 kW inwheel motor as an example, using Maxwell electromagnetic finite element analysis software, the electromagnetic finite element model of the inwheel motor was established, and the electromagnetic field was calculated. By choosing eight common working conditions of acceleration and overload, the distribution of electromagnetic losses and the law of numerical variation of each component of inwheel motor were analyzed. From the analysis results, it could be seen that the stator iron loss increased with the increase of rotational speed, but did not change with the increase of overload multiple. The core loss of rotor could be neglected. The eddy current loss of permanent magnet increased with the increase of acceleration and overload at the same time, but the effect of acceleration condition on it was stronger. The copper loss of windings was mainly affected by the change of overload multiple, which accounted for the largest proportion of total loss and was the main heat source. An important reference for the analysis of temperature field and the design of cooling structure of inwheel motor was provided.