Development of Dual-Memory Motor Drives for Electric Vehicles

This paper proposes a dual-memory motor drive for electric vehicles (EVs). The dual-memory motor adopts a dual-magnet arrangement which incorporates two permanent magnet materials for hybrid excitation, namely neodymium-iron-boron (NdFeB) and aluminum-nickel-cobalt (AlNiCo). The NdFeB PMs provides the main air-gap flux, while the AlNiCo PMs can be regulated online for main flux strengthening or weakening. Therefore, the dual-memory motor drives can achieve a high starting torque by flux strengthening and extend its constant power operation range by flux weakening. Firstly, the proposed motor structure is presented. Secondly, its operation principle is discussed. Thirdly, the drive system and control scheme are developed for EVs. Finally, by using the circuit-field-torque time-stepping finite element method (CFT-TS-FEM), the performance of flux strengthening is verified, and experiments are also carried out to assess its flux weakening capability.