纯电动汽车的再生制动力分配策略研究

Study on Regenerative Braking Force Distribution Strategy for Pure Electric Vehicle

针对电动汽车在低附着路面的驾驶稳定性的问题进行研究。因为汽车在冰雪路面制动时,大多数制动力分配方案以再生制动为主要制动力,此时很有可能发生抱死,从而发生汽车驾驶稳定性下降。本文中提出了一种在制动力分配上加入滑移率的控制方法,该方法以纯电动汽车为模型,设计出以汽车滑移率为控制对象的滑膜控制器。该控制方法在改进再生制动力分配策略上,特别在小制动强度时,电动汽车驱动轴有趋于抱死的情况立即减少再生制动力,使电动汽车恢复原有的稳定性。仿真结果表明:在强度恒定的制动工况下,电动汽车模型具有良好的驾驶稳定性,电动汽车模型在需要频繁制动的城市路况下,能量回收率提升了4.1%。

The electric vehicle′s stability where adhesion coefficient is low was studied.Wheels were likely to looked during the vehicle were braking on icy and snowy pavement,because the major of braking force was regenerative braking force this moment.The resulting was the deterioration of its stability.Based on the pure electric vehicle mode,the braking force strategy of inputting wheel slip ratio is proposed in this paper.A controller with sliding mode control was designed for controlling slip ratio.This control method was used to improve the regenerative braking force distribution strategy.Especially with being small braking strength,it will immediately reduce the regeneration power when slip rate of vehicle exceeded the prescribed slip rate,restored the electric vehicles to its original stability.Then the final simulation results show that the electric vehicle model that used sliding mode controller has good driving stability with braking condition of constant strength,and the braking energy recovery rate is increased by 4.1%in frequent braking conditions.