纯电动汽车复合储能系统参数匹配及控制策略

Parameter Matching and Control Strategies of Hybrid Energy Storage System for Pure Electric Vehicle

为了解决纯电动汽车用动力电池功率密度低、大电流充放电能力差和循环使用寿命短等问题,以超级电容与动力电池组成的复合储能系统为研究对象,提出了基于典型循环工况的复合储能系统参数匹配优化方法;在满足各循环工况对复合储能系统能量需求与功率需求的前提下,以动力电池容量和超级电容容量为优化变量,对复合储能系统总成本与总质量进行了多目标优化。在此基础上,根据电机需求功率及超级电容荷电状态,以减小动力电池输出电流为目标,制订了基于滤波思想的基本规则控制策略;为更好地适应不同的循环工况,提出了复合模糊控制策略,其中主模糊控制器基于电机功率需求、动力电池荷电状态和超级电容荷电状态得到动力电池输出功率初次分配系数,子模糊控制器根据电机功率需求和超级电容当前荷电状态与其目标值的差值得到动力电池输出功率修正系数,二者协同作用得到动力电池最佳输出功率,并对整车动力性、经济性、动力电池电流和温度特性进行了仿真分析。结果表明:采用所提出的复合储能系统及2种控制方法与单一动力电池的纯电动汽车相比,百公里加速时间分别缩短了6.89%和9.85%,NYCC工况下总能耗分别降低了14.15%和19.08%,动力电池最大电流分别降低了63.4%和65.17%,动力电池温升分别降低了22.87%和61.53%。

In order to solve problems of low power density,poor ability of heavy current charge and discharge and short cycle life of power battery used in the electric vehicle,a new hybrid energy storage system（HESS）composed of battery and ultracapacitor（UC）was taken as an object of research.The optimal approach of parameter matching for HESS was proposed under the typical cycle condition.Under the premise of satisfying the energy demandand power demand of HESS,the multiple objective optimization of the total cost and the total mass was carried out by taking the power battery capacity and the UC capacity as the optimization variables.On this basis,considering motor demand power and UC state of charge,the filtration-based rule control strategy was established to reduce output current of power battery.And the hybrid fuzzy control strategy was put forward to better adapt to different cycle conditions.The primary power distribution coefficient of power battery was obtained by the main fuzzy controller on the basis ofthe motor power demand,power battery state of charge and UC state of charge.Meanwhile,the modified power distribution coefficient of power battery was obtained by the sub-fuzzy controller based on the motor power demand and the difference between the current state of UC and the target value.That is to say,the optimal power coefficient of power battery was obtained by dint of two controllers.The vehicle power performance,economy,and power battery current and temperature characteristics were simulated and analyzed.The results show that,compared with the pure electric vehicle equipped with the conventional battery energy storage system,the proposed HESS with the two control strategies has the better performance.The acceleration time within 100 kilometers decreases by 6.89% and 9.85%,respectively,whilst the total energy consumption under NYCC condition decreases by 14.15% and 19.08%.The maximum battery output current under NYCC decreases by 63.4% and 65.17% respectively,and power battery temperature rise decreases by 22.87% and 61.53%,respectively.