A permanent-magnet flux-mnemonic integrated-starter-generator for hybrid electric vehicles

In this paper, a new permanent magnet (PM) flux-mnemonic brushless machine is proposed and implemented as an integrated-starter-generator (ISG) for hybrid electric vehicles (HEVs). The key is to integrate the concept of memory motor, namely the flux-mnemonics, with the doubly-salient PM (DSPM) machine. Hence, it offers the advantages of mechanical robustness, controllable air-gap flux, and efficient online PM magnetization. By further employing the outer-rotor and double-layer stator topology, the proposed ISG achieves direct-drive capability and low armature reaction. Therefore, according to the HEVpsilas working condition, the proposed ISG can operate in various magnetic field situations, including offering a very high starting torque for HEV cold cranking and maintaining constant voltage output for battery charging. By using the finite element method (FEM) and mathematic modeling, the steady-state and dynamic performances of the ISG are analyzed. A prototype is also designed and made to confirm the validity of the proposed ISG.