轴向磁通轮毂电机新型冷却系统涡流损耗优化

Optimization of Eddy Current Loss of the New Cooling System of Axial Flux Motors

针对定子无磁轭轴向磁通电机内部冷却系统存在涡流损耗,导致电机效率降低、温升高的问题。本文以车用轮毂电机为研究对象,对一种定子无磁轭轴向磁通电机冷却系统进行建模;通过对电机运行过程中冷却系统涡流损耗进行仿真分析,并对电机进行二维有限元等效,研究翅片涡流损耗产生机理。在此基础上,从3个不同角度对涡流损耗进行优化,通过优化定子齿形以降低翅片处磁场强度,通过磁热耦合分析优化翅片高度,通过对翅片开槽以增大电涡流路径电阻,最终将涡流损耗降至原来的32.7%。通过对试制样机进行实验测试,结果表明:有限元仿真和实验测试一致性较高,通过优化后的电机在不同转速下效率均有所提升,转速4000 r/min下优化后的电机效率较未优化高出3.1%。

The internal cooling system of stator yokeless axial flux motor has eddy current loss,which leads to the reduction of motor efficiency and temperature increase.In this paper,a cooling system of a stator yokeless axi⁃al flux motor is modeled with a vehicle hub motor as the research object.Through simulating and analyzing the eddy current loss of the cooling system during the operation of the motor,and performing two⁃dimensional finite element equivalence of the motor,the mechanism of eddy current loss of fins is further investigated.Based on this,the eddy current loss is optimized from three different perspectives,namely,optimizing the stator tooth shape to reduce the magnetic field strength at the fins,optimizing the fin height through magneto⁃thermal coupling analysis,and slotting the fins to increase the eddy current path resistance,which finally reduces the eddy current loss to 32.7%of the origi⁃nal one.The experimental tests of the prototype are carried out.The results show that the finite element simulation and experimental test results are consistent and the efficiency of the optimized motor is improved at different speeds,with the efficiency of the optimized motor 3.1%higher than that of the unoptimized motor at 4000 r/min.