混合动力汽车用混合能量存储系统的设计

摘要

针对动力电池在混合动力汽车中频繁大功率充放电的问题,采用了电池和超级电容并用的能量存储系统,利用超级电容高功率特性来改善储能系统的性能.本文研究了电池与超级电容直接并联和主动并联两种混合能量存储系统,后者采用零电流转换软开关直流变换器来连接超级电容和电池.在Matlab Simulink平台建立零电流转换软开关直流变换器的动态模型、超级电容和电池模型,并在AVL Cruise中进行仿真.结果表明:直接并联方案不能充分发挥超级电容的能力；而主动并联方案降低了纯电动工况和制动能量回收工况下电池的峰值电流,电池端电压变化范围缩小,能量效率比单一电池的能量存储系统提高了14.92％.另外,由于采用了模糊PID控制算法,改善了动态响应性能.%In view of the problem of power batteries being frequently charged and discharged at large power in hybrid electric vehicle, the battery/ultra-capacitor hybrid energy storage system ( B/UC HESS) is adopted, which takes advantage of the high power characteristics of ultra-capacitor to improve the performance of storage system. In this paper, two schemes of B/UC HESS are studied :direct battery/ultra-capacitor parallel connection and active battery/ultra-capacitor parallel connection, in which the latter uses DC-DC converter with zero current transition soft switching as interface to connect battery and ultra-capacitor. The dynamic model for the DC-DC converter and the models for battery and ultra-capacitor are set up with Matlab simulink and a simulation is conducted with AVL Cruise. The results indicate that the direct parallel scheme doesn't take full use of the capability of ultra-capacitor , while with the active parallel scheme the peak current of battery lowers in pure electric driving and regenerative braking conditions, the variation range of battery end voltage reduces, with an energy efficiency 14. 92 % higher than that of sole battery energy storage system. In addition, its dynamic response performance also improves due to the use of fuzzy PID control algorithm.