Study On Parameter Matching Of Battery Pack And Control Strategy For Hybird Electric Bus

With the global warming, the shortage of natural resources and environment pollution,hybrid electric bus gradually become ease city traffic pressure, energy saving andenvironmental protection of the important carrier.Based on a hybrid power city busoperation situation analysis research, the solutions for high fuel consumption and lowefficiency of electric system in the actual operation process were proposed. Main contentsare as follows:1) The characteristics of nickel-hydrogen battery packs for the real vehicleconfiguration were analyzed. The charge and discharge process based on electrochemicalreaction mechanism were analyzed. Test on charge and discharge of nickel-hydrogenbattery packs and the HPPC test were made. The charge and discharge characteristics,capacity efficiency characteristics and the resistance characteristics of nickel-hydrogenbattery packs were analyzed.2) RC model of battery that reflects the characteristics of nickel-hydrogen battery packswere created on the basis of characteristic test. The main function of the model is toestimate the SOC and temperature of nickel hydrogen battery packs.3) Statistical analysis of the actual operating condition of a hybrid bus is made. andthree operating conditions were divided based on the characteristics of load in the runningprocess. The parameters matching of power battery were finished on the basis of theanalysis on working condition, combined with matching method of traditional powersystem.4) Logic threshold control strategy used by real vehicles was analyzed. In view of theactual operating condition and characteristics of nickel-hydrogen battery pack, the logicthreshold control strategy was optimized through fuzzy control method, The optimizingobjective was to reduce fuel consumption and to improve the operating efficiency of thepower system in ensuring the dynamic performance of vehicle. Fuzzy optimal controllersfor different operating modes were established based on the logic threshold controlstrategies used by original cars. Then redistribute the energy of power system in each mode. 5) A simulation model of the vehicle was built in cruise simulation software, andco-simulate with the control strategy built by simulink. Simulations of Dynamic，economic，working point distribution and efficiency of electric system in the three differentoperating conditions--light-loaded, medium-loaded and overloaded condition were carriedout. The simulation results show that the effect on the dynamic characteristic of vehicle issmall and the economy of vehicle declines after optimization of Fuzzy control strategy,itimproves the economy of vehicle, meanwhile the spread of operating point in high-efficientof the engine, motor, and battery increase, and the average efficiency is improved.The main innovation of this paper are as follows:1） Matching of power battery were finished on the basis of the analysis on matchingmethod of traditional power system,combined with full consideration to the actualrunning conditions of vehicle on battery power demand.2） Based on the analyze of logic threshold control strategy used by real vehicles，through the actual operating condition and characteristics of nickel-hydrogenbattery pack, the logic threshold control strategy was optimized through fuzzycontrol method,...