The Moving Characteristics And Energy Distribution Of Hub Motor EV Driving System

As the environment protection and energy resources issue being paid an increasingly attention, the EV(Electrical Vehicle) has shown a trend of quickly developing due to its characteristics of zero-emission and near to zero-emission. It has been widely used because of simple and compact structure, taking up small space. In most electric driven systems of EV, as a new one, hub-motor driving system is becoming the focus in the area of EV. With the motor fixed in hub directly, it omits the transmission links such as the clutch, gearbox and so on. The vehicle's structure and transmission efficiency get optimization. So it is going to be the developing direction of EV.This paper does research on the dual-rear-wheel driven hub motor EV, and mainly analyses the performance and controlling of the driving system of EV based on hub-motor driven.Firstly, the driving mode is decided according to the characteristics of different types of hub motors, and thus a appropriate type of motor is selected and the relating working principle and speed regulation characteristic are briefly analyzed. Then the dynamic simulation model of the EV is created, with the tyre adopting a uniform part experiment exponent model since both the longitudinal and lateral force as well as the tracks lip rate can easily be calculated from this model which also has a better interface system connecting with the overall-vehicle controlling system. The overall-vehicle dynamic model is established through adopting displacements of both X and Y direction, the three degrees of freedom of the yaw angle and the four-wheel turning. Brushless DC motor model is adopted as the motor model for its simplicity. The controlling system model takes the two different parameters of speed and torque as the controlling the variables. At last the simulation of the dynamical overall-vehicle is conducted in the Simulink environment due to its great functionality. Each single subsystem was created and connected together, and then through running the program the results and the relative analysis are made. This paper mainly compares the power performance, the control stability and the differential control effectivity based on the two types of controlling variables: speed and torque.This topic combines the computer simulation technology with the current studying state. After driven by hub-motor, if a suitable differential control method is chosen, the vehicle can obtain an excellent steering stability and reduce tyre abrasion, although the transmission links have been omitted. This paper offers the supports for the improvement of differential control technology and further research of EV.