电动汽车用模块化永磁游标电机的设计与分析

Design and Analysis of a Modular Permanent Magnet Vernier Machine for Electric Vehicle Application

针对电动汽车驱动系统,设计并分析一种模块化的双转子轴向磁通永磁游标机,即双转子轴向磁通定向永磁游标电机(dual-rotoraxial-fluxalignedpermanentmagnetvernier machine,DR-AFAPMVM)。采用双转子拓扑结构,由于两侧采用模块化多层双磁通场设计,可以获得比单转子更高的转矩密度。该文验证了辐条式永磁体排列方式、双定子电机的优点。为了进一步增加电磁转矩密度,提出2种类型的三定子电机,并对其进行比较。为了提高分析法的计算精度,提出气隙磁密的磁通校正系数,通过有限元分析法进行验证。最后,通过仿真验证DR-AFAPMVM的效率图、速度范围和运行点等性能,说明其应用在电动汽车中的驱动能力。

In this manuscript,a modular dual-rotor axial-flux permanent magnet vernier machine was designed and analyzed for the electric vehicle(EV)drive system,namely the dual-rotor axial-flux aligned permanent magnet vernier machine(DR-AFAPMVM).By adopting the dual-rotor topology,the machine can achieve higher torque density than the single-rotor one due to the modular multi-layer double flux filed design in both sides.In order to highlight the advantages of the proposed machine,two types of one-stator one-rotor vernier machines with surface-mounted and spoke-type magnets were compared firstly,which verified that spoke-type magnets had the so called"flux focusing"ability to increase air gap flux density.Compared to the above single air gap machine,the axial-direction electromagnetic force of rotor in the double-stator machine was largely reduced,which was significant for the axial-flux machine.Furthermore,in order to increase the electromagnetic torque density significantly,two types of three-stator two-rotor machines were designed,where comparative evaluation of the proposed DR-AFAPMVM and the dual-rotor axial-flux unaligned permanent magnet vernier machine(DR-AFUPMVM)were performed by using finite element analysis.In detail,a flux calibration coefficient considering magnet air gap leakage flux and radial direction leakage flux was proposed to contribute to the analytical model.Performance of the proposed machines was compared by both analytical method and finite element analysis,which verified the accuracy of the improved analytical method.Finally,the performance of DR-AFAPMVM,such as efficiency map,speed range and operation points,was verified by simulation to illustrate its drive ability in EV application.