Performance evaluation of an integrated starter alternator using an interior permanent magnet machine

There is a worldwide effort in using more and more electrical-driven auxiliaries in road vehicles. The integrated starter-alternator (ISA) is an electric drive in which the functions of starting engine and generating electric power are fulfilled by only one electric machine, instead of two separate electric machines in a traditional automotive vehicle. The interior permanent magnet (IPM) synchronous machines are attractive for the ISA application thanks to their characteristics: the flux-weakening capability, the high efficiency, the high power density and the high overload capability. This study reports some analysis and test results of an ISA that has been developed using a fractional-slot IPM machine. The results confirm that the IPM machine configuration is an excellent candidate for this application.