Design, Analysis and Experimental Evaluation of a Novel High-Speed High-Power Ferrite IPM Machine for Traction Applications

The paper presents the design and experimental evaluation of a novel (12000 rpm, 80 kW) Ferrite Interior Permanent Magnet (IPM) machine for traction applications, benchmarked against a rare-earth IPM machine. First, the Ferrite IPM machine concept employing both circumferential and axial PMs is introduced, and an extensive sizing exercise to maximize the contribution of the axial PMs is undertaken, resulting in the adoption of a multi-stack rotor concept. Furthermore, to minimize the use of computationally intensive 3D Finite Element Analysis (FEA), an equivalent 2D-FEA model is proposed, and employed for design optimization. 3D-FEA is only employed for the calibration of the 2D model and demagnetization studies. A full-size prototype Ferrite IPM traction machine is developed, and tested, and it is shown that a maximum efficiency of 96% comparable to that of the benchmark machine can be achieved with about 23% lower material cost. More importantly, over the Worldwide Harmonized Light Vehicle Test Procedure (WLTP) driving cycle, the Ferrite IPM traction machine exhibits about 30.67% less energy loss compared to the benchmark rare-earth IPM machine.