永磁起动/发电机在弱磁条件下磁场与涡流损耗分析

Analysis of Magnetic Field and Eddy Current Loss of Permanent Magnet Starter/generator under Field Weakening Condition

涡流损耗是导致永磁同步电机热退磁的主要原因,同时电动汽车应用场合常处于弱磁状态,对比不同转子结构的永磁同步电机在弱磁状态时的涡流损耗具有研究意义。本文选取内置式V型和双V型两种转子结构的35 kW的永磁同步电机为研究对象,在永磁体用量与分块相同的前提下,建立二维有限元模型,分析不同弱磁条件下的两种转子永磁同步电机磁场变化规律与永磁体涡流损耗之间的关系。结果表明,在相同弱磁条件下,双V型转子结构的电机凸极率大28%,弱磁性能好,永磁体磁体涡流损耗小40%。最后,制作V型转子集成起动/发电机样机,并采用空载反电势压降法进行实验,实验结果与仿真结果趋势相同,验证了仿真分析的有效性。

Eddy current loss is the main cause of thermal demagnetization of permanent magnet synchronous motors(PMSMs).Since the motor is often in a field weakening state in electric vehicle applications,it is meaningful to compare the eddy current loss of PMSMs with different rotor structures in the field weakening state.In this paper,a 35 kW PMSM with built-in V-shaped or double-V-shaped rotor structure is selected as a research object.On the premise that the amount of permanent magnet is the same as that of blocks,a two-dimensional finite element model is established to analyze the relationship between the magnetic field variation law of PMSM with two types of rotor structure and the eddy current loss of permanent magnet under different field weakening conditions.Results show that under the same field weakening condition,the motor with the double V-shaped rotor structure has a 28%larger salient pole ratio,a better field weakening performance,and a 40%smaller permanent magnet eddy current loss.Finally,a prototype of integrated starter/generator motor with V-shaped rotor was fabricated,and the no-load back EMF voltage drop method was used to conduct experiments.The experimental results agree with the simulation results,which verifies the effectiveness of the simulation analysis.