A Permanent-magnet double-stator integrated-starter-generator for hybrid electric vehicles

This paper presents a new permanent magnet double-stator integrated-starter-generator (ISG) for hybrid electric vehicles (HEVs). Compared with conventional PM electric machines, it has the advantage that currents of both the inner and outer stators produce electromagnetic torque and two air-gaps can deliver the output torque, thus improving the torque density and providing a high starting torque for cold cranking. Because of the nature of double-stator windings, the machine can flexibly change their connections, hence providing a constant output voltage over a wide speed range for battery charging. By using time-stepping finite element method (TS-FEM), the steady-state and dynamic performance of the machine is analyzed. Hence, due to the high starting torque and good controllability, this proposed ISG is desirable for HEVs application. A three-phase 22-pole 2 kW prototype is designed and built for experimentation verification.