Design and Control of a Doubly-Excited Permanent-Magnet Brushless Integrated-Starter-Generator for Hybrid Electric Vehicles

This paper presents a new doubly-excited permanent-magnet (PM) brushless machine as the integrated-starter-generator (ISG) for hybrid electric vehicles (HEVs). The proposed machine adopts both PM and DC field winding excitations in the inner stator to produce magnetic field. Meanwhile, an additional air bridge shunt with each PM is used to amplify the flux control ability. Hence, by tuning a small DC field current, the machine can flexibly regulate the airgap flux distribution up to the range of 9 times. Therefore, through flux regulation, the proposed machine not only can provide a very high starting torque for HEV cold cranking, but also can maintain constant voltage output for battery charging over wide ranges of speeds and loads. A three-phase 36 slots 24 pole-pair prototype has been made. The time-stepping finite element method (TS-FEM) and experiments are implemented to verify the performance of the machine.