Study On Fuzzy Logic Based Energy Management Strategy Of ISG-type Speed Coupling Hybrid Electric Vehicle Based On DP Algorithm

With the development of human society, the requirements of sustainable energysaving and environmental protection are gradually increasing, this leads to the rapiddevelopment of clean-energy vehicles. Because of the good cost performance ratio,hybrid electric vehicle which is a member of the clean-energy vehicles has been widelyconcerned in product development. There are multiple power sources in a hybridelectric vehicle, so the improvement of automobile performance depends on theeffective energy management of power sources. Therefore, energy management strategyis one of the core problems when we study hybrid electric vehicles.In view of the fuzzy logic has been widely used in modern industry, however, thedesign of fuzzy control based energy management strategy mainly depends on artificialexperience, which is not only a waste of time but also is difficult to obtain the desiredresult. This limits the application of fuzzy logic to a real vehicle. To promote thepractical application of fuzzy logic, a new method that used to design control strategy isput forward. By using the dynamic programming algorithm to design a fuzzy logicbased energy management strategy which is to improve the fuel economy of hybridsystem and maintain the balance of battery SOC. For this purpose, these mainresearches are as followed.①Mathematical models including engine model, ISG motor model, planetary gearsystem model and the transmission model were built based on the structure andparameters of the speed coupling hybrid vehicles using Matlab/Simulink software.Hybrid electric vehicle simulation model is consist of those component models.②In this paper, all kinds of operating mode and the energy flow path in thecorresponding mode of hybrid electric vehicles have been analyzed. Used demandedpower and battery SOC as threshold parameters in drive mode and braking strength andbattery SOC as threshold parameters in brake mode to design a rule-based energymanagement strategy. Then the simulation results which used to evaluate the fuzzycontrol strategy were obtain by simulating through combining with the hybrid electricvehicle simulation model.③Then introduced dynamic programming algorithm which is one of the corealgorithm of the global optimal energy management strategy. A global optimizationperformance simulation of ISG(Integrated Starter-Generator) electric variable transmission HEV(Hybrid Electric Vehicle) has been operated in the certain cycle byusing the Dynamic Programming algorithm. The DP simulation results are the optimumfuel economy of the hybrid system in theory.④Through studying the design principle of fuzzy controller, the input and outputvariables of fuzzy controller have been determined. The rules and strategy of fuzzycontrol have been built by analyzing the simulation results of DP algorithm. Bycomparing the simulation results of three kinds of energy management strategy, therationality of fuzzy logic based energy management strategy has been verified.According to the above research work, a good method for designing energymanagement strategy has been put forward. This has a positive significance to improvethe performance of hybrid electric vehicle and promote the practical application offuzzy logic based energy management strategy.