Evaluation of Efficiency-Shifting Permanent Magnet Motor in Electric Vehicle

Abstract

We have designed an efficiency-shifting radial-axial hybrid permanent magnet synchronous machine (ES-RA-HPMSM) for use in an electric vehicle (EV) and compared the maximum driving distance $(d_{max})$ and ratio of the dmaxto the cost of the motor system with transmission $(d_{max}/M_{cost})$ of the conventional non-efficiency-shifting motor (ES-M) used in current EVs with either a single-or two-gear transmission (TR). An EV model, comprising a driver, motor and inverter, battery pack, TR, wheel, and chassis model, was constructed using MATLAB software. The proposed ES-RA-HPMSM with single-gear TR and four non-ES-M with either single-or two-gear TR were evaluated under typical city, highway, and city+highway drive cycles. The results show that the proposed ES-RA-HPMSM not only extends the $d_{max}$ by 25.4 and 46.8 miles in the city, 30.4 and 44.9 miles in the highway, and 37.8 and 19.5 miles in city+highway drive cycles but also exhibits higher $d_{max}/M_{cost}$ by 4 and 97 % in the city, 21 and 86 % in the highway, and 20 and 92 % in the city+highway drive cycles, compared to the conventional motor with single-or two-gear TR, respectively.