The Research Of The Direct-drive In-wheel Motor Used By EV

Developing the new energy and the low carbon economy is an important task to build a resource-conserving and environment-friendly society. So it is imperative that the traditional automobile industry gradually transform into the electric vehicle industry.The electric drive system is one of the key techniques of all electric vehicle research, whether these cars are hybrid electric vehicles or electric vehicles. However, the in-wheel motor drive system is the highest potential driven-mode among many of the electric driving systems. And one of the core techniques of solving the electric vehicle’s in-wheel motor drive assembly is to find a kind of low speed and high torque motor, which can meets the requirements of in-wheel motor driving electric cars.This thesis chooses a kind of miniature electric car as the prototype, using a new outer rotor permanent-magnet vernier machine as the drive motor. It mainly researches the operation performance and the flux-weakening capability of the motor. At last, it shows that the new structure of the motor is appropriate for the drive motor of the in-wheel drive electric cars by analysis and research.First of all, this thesis introduces the domestic and international research present condition of electric vehicles and the in-wheel motor. And it provides detailed introduction on the characteristics of all kinds of electric vehicles’ drive motor. It introduces the characteristics of two kinds of in-wheel motors, which are both deceleration motor and direct-drive motor. And it focuses on the structure and principle of the outer-rotor permanent-magnet vernier machine for direct-drive in-wheel motor.And then, it determines the parameters of the direct-drive in-wheel motor from the vehicle dynamic performance. And it has a detailed analysis and designation on electromagnetic of the motor.Then, it analyzes the electromagnetic characteristics of the motor by using the finite element analysis software ANSOFT. And it builds a2D finite element model for the prototype. It has a detailed analysis on the motor’s no-load and load characteristics.At last, it emphatically introduces the flux-weak ability of the direct-drive in-wheel motor. And it calculated the motor’s region of the constant torque and constant power by using the finite element method. Then it can confirm the motor’s Maximum speed. By the comparison of the needs of the electric car it indicates that the motor is completely suitable for direct-drive in-wheel electric vehicle as a drive motor.