A High Torque Density Flux-Focusing Halbach Magnetic Gear for Electric Vehicle Applications

Due to the contact free and low maintenance features, magnetic gears (MGs) have been increasingly investigated to amplify the torque of electric motors in electric vehicles (EVs). In order to meet the requirements of propelling EVs, it is essential to design the MG with a high torque density. In this paper, a novel flux-focusing Halbach MG (FFHMG) is proposed, which combines the advantages of flux focusing and Halbach permanent magnet (PM) arrays. A parameter sweep optimization is implemented to increase the torque density and optimize the PM volume in the proposed FFHMG. The performance of the proposed FFHMG is then investigated through both 2D and 3D finite element analysis (FEA). According to the simulation results, the proposed FFHMG can achieve a torque density of 316.6 kNm/m ³ , and the torque per PM volume is 736.4 kNm/m ³ , which are significantly larger than those of the existing MGs and make the proposed FFHMG very suitable for EV applications.