PWM逆变器供电引起的轴向磁通非晶电机谐波损耗的解析计算

非晶合金材料具有出色的低损耗特性,适于用作高频电机的铁心,但PWM逆变器供电会导致高频电机谐波损耗严重增加。在电机初始设计阶段,快速准确计算出谐波损耗是轴向磁通非晶合金永磁电机设计及优化的关键。针对3D时步有限元计算耗时长的问题,改进现有多环等效模型的计算方法,推导了考虑PWM逆变器供电高次谐波电流影响的气隙磁通密度解析计算方法,并在此基础上推导了定子铁心损耗及考虑涡流反作用影响的转子涡流损耗的解析计算方法。将谐波损耗的解析计算值与样机实验值以及3D有限元计算值进行对比,结果显示谐波损耗的平均计算误差仅为9.69%,解析模型具有较高的计算精度。

Analytical Calculation of Harmonic Losses of an Axial Flux Amorphous Motor Caused by PWM Inverter Supplying

Amorphous alloys are considered as an appropriate core material for high-frequency motors because of their outstanding low power loss characteristics. When supplied by a PWM inverter, however, the harmonic losses of high-frequency motors will enormously increase. The key for designing and optimizing an amorphous alloy axial-flux permanent magnet motor is the fast and accurate calculation of harmonic losses during the original designing stage. In this paper, because of the large time consuming of three dimensional time step finite element analysis method, the present multilayer coupled model is further improved. An analytical method of air gap flux density is derived which can take high order carrier harmonics into account. The analytical methods of stator core losses and rotor eddy current losses are then deduced in consideration of the influence of eddy current reaction. The analytical calculation results of harmonic losses are compared with measured results and those obtained by the three dimensional FEA method. It is shown that the average calculation error of rotor losses is 9.69％, which means the improved analytical method features in high accuracy.