I. Introduction
Currently, with the constant advancement of vehicle electrical equipment, it is inevitable to expand the power generation capacity of the vehicle generator. However, due to the limited installation space in vehicles, it has significant technical advantages to increase power density and power generation efficiency without increasing the size of the generator. Simultaneously, in order to ensure the stability of the vehicle power supply system, the magnetic field of the generator needs to be easy to adjust to achieve stable voltage output under varying working conditions.