Research On Hybrid Bus Energy Allocation Strategy

Power allocation strategy is the key technology of hybrid electric vehicle. Inthis thesis, the hybrid bus with planetary gear was researched, and the simulationmodel was established on the simulation software ADVISOR.The characteristics of the battery and super capacitor were analyzed, andmodels of battery and super capacitor were established on ADVISOR. In order toreduce loss and enhance controllability, a special structure connecting the DC-DCconverter with the load, was selected. The forward simulation model of compositepower was established on MATLAB/Simulink. The operation state of the compositepower supply was analyzed. The logic-based and the fuzzy-logic based energymanagement strategy were studied expressly. The simulation model of the hybridbus with the composite power supply was established on ADVISOR. The simulationresults have proved the proposed energy management strategy effective.The hybrid bus, which employs a planetary gear set to connect one internalcombustion engine with two motors, can take advantages of both series and parallelhybrid system by controlling power flow. Based on the working characteristics,parameters of vehicle’s engine, motor, and generator can be identified. To bespecific, the power flow control adjusts not only the amount and direction ofmechanical and electrical power, but also the operating point of engine. This thesisintroduced a power distribution strategy, which used control map to minimize theloss in power flow, meanwhile, operate engine on efficient point. The control mapwas obtained by optimum searching, which saught efficient operating point for thegiven speed, load and battery charge/discharge power. Then energy allocationstrategy of drive chain, consisting of rule-based energy allocation strategy andoptimal vehicle efficiency energy allocation strategy, was verified on ADVISOR.