Energy Management System Control Strategy Of Combined Energy Storage System On Electric Vehicle

Development of new energy vehicles is an important way to solve theenvironmental pollution and the depletion of oil resources, electric vehicles (EV) hasincomparable advantages in energy saving and environmental protection with theadvantage of high efficiency, low noise and zero emission. However, the developmentof EV was hindered due to the limit of battery technology, which was badly effecteddynamic performance and driving range of EV. Ultracapacitor is a new energystoragewith the advantage of high power density, rapid charge&discharge performance andlong life time, the batteries and ultracapacitors were combined used in the energystorage system of the EV can not only meet the vehicle dynamic demand，but alsoimprove regenerative braking energy recycling performance, while extend the batterylife and improve the EV power and economy performance.First, this paper analyzed the performance characteristics of various power energystorage device and compared the strengths and weaknesses of each performance,lithium-ion battery and ultracapacitor were selected to compose the synergic electricsystem based on the performance requirements of the EV power; Second, lithium-ionbatteries, ultra-capacitors and a bi-directional DC/DC converter operatingcharacteristics were analyzed, then the simulation model of each components wereestablished in Matlab/Simulink environment based on their characteristics, thesimulation model of synergic electric system was established based on the compositionof the structure of the synergic electric system; Third, according to the vehicleconfiguration and performance requirements, with the cycle run of vehicle condition,the parameters of synergic electric system was matched and optimized based on theeconomic performance of the synergic electric system; Finally, two methods of controlstrategies such as real-time control method and fuzzy control method wererespectively designed, ADVISOR was used as a simulation platform in order to studythe performance of the synergic electric system in different driving conditions. Simulation results show that the ultracapacitor had a prominent effect of "clippingpeak and filled channel" for the lithium-ion battery, and avoided sharp current chargeand discharge of the lithium-ion battery, which protected lithium-ion battery andrecycled regenerative braking energy, EV with synergic electric system can improvedramatically in terms of dynamic performance and economic performance comparedwith a single power.