A Novel Delta-Type Hybrid-Magnetic-Circuit Variable Flux Memory Machine for Electrified Vehicle Applications

This article focuses on a newly developed 30-kW hybrid-magnetic-circuit variable flux hybrid magnet memory machine (HMC-VFMM) with a delta-type magnet arrangement for automotive traction applications. The proposed HMC-VFMM can improve the torque capability with effective utilization of flux concentration due to delta-type hybrid magnet arrangement while decreasing the required magnetization current level due to the dual-layer (DL) permanent magnet (PM) design. The presence of the parallel magnetic circuit can permit a satisfactory magnetization state (MS) manipulation range. Meanwhile, the DL series-type PM configuration can maintain beneficial unintentional demagnetization withstand capability. The machine topology and operating principle are described. Furthermore, the magnetic circuit model of the proposed machine structure is developed to identify and confirm the feasibility of the electromagnetic performance enhancement. Besides, the electromagnetic characteristics of the proposed HMC-VFMM are comprehensively analyzed and compared with those of a benchmark delta-type PM machine based on the Nissan Leaf drive motor. Finally, a 30-kW prototype is manufactured and tested to verify the feasibility of the proposed HMC-VFMM design in the potential context of electric vehicle applications.