A Study On Regenerative Braking System Of Pure Electric Vehicle Integrated Control Strategy With ABS

Under the dual pressure from the energy resource and the environment, increasing demands from the world are the different kinds of new energy vehicles, and the pure electric vehicle is almost zero-emission, it’s the reason that it becomes the goal of the contemporary car company pursuiting persistently.In order to follow the world’s main trend of energy conservation and environmental protection, the pure electric vehicles will carry the regenerative braking system to recover a part of the braking energy. However, the regenerative braking system alone can neither meet the braking requirements of the pure electric vehicles, nor the braking safety and stability. Therefore, the pure electric vehicles need a hydraulic braking system equipped with ABS. Learnt from the external characteristics of motors, the torque of regenerative braking system is constantly changing with the changes of the speed, and response speed is fast. In contrast with that are the stable torque required by ABS and hysteresis of the hydraulic braking system. They are the main contradictions of compatibility controlling.In order to resolve these contradictions, on the basis of a lot of researching work, this article thinks that the distribution of the front and rear shaft braking force is the main factor of vehicle braking safety and stability. Therefore, there is a discussion about the distrubution of the front and rear shaft braking force in the pure electric vehicles equipped with regenerative braking system, it makes the distrubution can sitill meet the ECE braking requirements of the regulations after adding the torque of regenerative braking system, thus ensuring the car’s braking safety and stability.However, the contradiction between the changing torque of the regenerative braking system and the hysteresis of hydraulic braking system has not been effectively resolved.Because of the logic threshold control strategy has widely used on traditional vehicles’ABS, this artical made some minor adjustments based on it:set up a reached easily logic threshold of braking deceleration and one of slip ratio,they can be reached before the logic threshold of the hydraulic braking system’s ABS, just because the regenerative braking system can respone immediately. If it forecast that the ABS need to release the pressure of hydraulic braking system, ABS should do no actions. But if pressure increased demand was forecasted, ABS should increase the pressure immediately,in order to alleviate the instability cause of the hysteresis from hydraulic braking system.In order to verify the integrated control strategy of regenerative braking system and ABS, this article established the model of the distribution of the front and rear shaft braking force and the model of the motor’s braking force and the model of the integrated control strategy based on ADVISOR2002.In addition, some simulations were done at last.According to results of the simulations, the distribution of the front and rear axles’braking forces in the pure electric vehicles, involved in this article, can meet the regulations.lt can not only brake effectively, but also partly recover a part of the braking energy,achieving the effect of integrated controlling between regenerative braking system and ABS.