Comparison and Analysis of Flux-Switching Permanent-Magnet Double-Rotor Machine With 4QT Used for HEV

The use of double-rotor machines (DRMs) for hybrid electric vehicles (HEVs) has attracted considerable attention due to their compact structure and high torque density. Compared with the conventional four-quadrant transducer (4QT), the proposed flux switching permanent magnet double-rotor machine (FSPM-DRM) has PMs located in the stator, and can offer better performances in terms of magnetic coupling and torque ripple, which are especially important for DRM control in HEVs. This paper presents a comparative analysis of the 4QT and FSPM-DRM by employing the finite element method (FEM). For a fair comparison, two topologies are designed under the same peripheral dimensions, current density, and copper loss. Considering the effect of skewed slots in the 4QT, the corresponding performances are calculated with multi-slice 2-D time-stepping FEM. The simulated results illustrate that the proposed FSPM-DRM offers larger output torque, lower torque ripple, and smaller magnetic coupling than the 4QT. Nevertheless, the eddy current losses in PMs and windings of the FSPM-DRM are higher than those of the 4QT. Experimental results of the FSPM-DRM prototype are also given to verify the validity.