Investigation And Simulation Of Combined Energy Storage System On Electric Vehicle

With the advantage of high efficiency, low noise and zero emission, electric vehicles (EV) are the leading solution in automobile industry under the pressure of environment pollution and growing oil shortage nowadays. But due to the limit of battery technology, dynamic performance and driving range of EV are badly effected, which hinder the development of EV. Well, as a newly developed energy source, Ultra-capacitor has the advantage of high power density, rapid charge & discharge performance and long life time, and are very suitable for high power need such as acceleration, brake and climbing of the vehicle. Combined Energy Storage System composed of batteries and ultra-capacitors combines their advantage and can not only meet the vehicle dynamic demand, but also improve regenerative braking energy recycling performance.This paper researched the Combined Energy Storage System of EV and firstly analyzed the performance characteristics of battery, ultra-capacitor and DC/DC converter. On the basis of that, the models of components of the system were respectively established using appropriate methods of modeling and the models were packed as separate modules with the idea of using module in order to apply to the models of the system. According to the control objectives of Combined Energy Storage System, two methods of control strategies, logical method and fuzzy method are respectively designed. After designing the parameters of Combined Energy Storage System and cycles of road, ADVISOR are used as a simulation platform in order to study the performance of Combined Energy Storage System. The results showed that ultra-capacitor had a prominent effect of "clipped peak and filled channel" for the battery, and avoided sharp current charge and discharge of battery, which protected battery and extended its life. What's more, from the result of simulation, ultra-capacitor can provide energy when electric vehicle is accelerating and recover energy when electric vehicle is braking. So it can effectively extend the vehicle continued driving mileages and electric vehicle using Combined Energy Storage System had better performance in both dynamic and economy compared with single-battery. At last, simulation performance of logic control strategy and fuzzy control strategy were compared, the simulation result showed that fuzzy control strategy had better robustness and real-time ability, and fuel economy was even better.