Design of Axial-flux Integrated Starter Generator Drive System for Hybrid Electric Vehicles

This paper proposed a design of axial-flux integrated starter generator (ISG) drive system in the application of hybrid electric vehicles (HEVs). The system contains an axial-flux permanent magnet synchronous motor (AFPMSM) and its drive, which are compact designed. A series water-cooling channel is designed from the drive to ISG. It reduces cables and space of cooling system, which also benefit to high torque density. A simple and optimized flux-weakening and DC current estimation method based on flux-oriented control (FOC) algorithm are implemented to achieve high-performance control. Considering the sensitivity of the device to the power-up sequence and safety of users, an active discharge algorithm is proposed to release the charge. The drive system is tested on the test bench by the host computer via CAN bus and has achieved good dynamic response characteristics and high efficiency.