Design and Optimization of Permanent Magnet Brushless Machine for Integrated Starter/Generator Applications

With the rapid development of hybrid electric vehicles, the performance of integrated starter/generator (ISG) needs to be further improved. In this paper, a single-stator single-rotor axial flux machine is designed and optimized to be used as the ISG. Firstly, the effects of stator yoke length, rotor yoke length, permanent magnet thickness and pole arc coefficient on the back electromotive force (EMF), output voltage, core loss and magnetic density distribution of the machine are analyzed by finite element simulation. Secondly, the response surface model and multi-objective optimization algorithm based on genetic algorithm are used to optimize the machine. The effectiveness of the optimization is verified by simulation, and the volume, mass and loss of the machine are reduced after optimization. Finally, the experimental prototype was made and the experiments are conducted. The performance of the machine under no-load and power generation conditions was tested, and the performance of the prototype under different speeds and loads was tested, meanwhile the temperature rise experiment was carried out.