Recent status and future prospects of integrated starter-generator based hybrid electric vehicles

The integrated starter generator (ISG) technique has been widely used in the past in hybrid electric vehicle (HEV) drive trains. Instead of 2 independent electric machines, as in conventional vehicles, the ISG functions both as a starting engine as well as a generator, which facilitates the generation of on-board electric power. In this paper, the usage of the ISG in various advanced HEV topologies, including mild HEVs, and different dual-voltage vehicular electrical systems, will be briefly reviewed and compared. In addition, the prime ISG options, including induction machine (IM), permanent magnet synchronous machine (PMSM), as well as the switched reluctance machine (SRM) will be investigated from the point of view of performance characteristics and efficiency requirements. The current status and major improvements in terms of future action plans, for popularly proposed ISG control strategies, will also be presented in this paper.