Study On Adaptive Equivalent Consumption Energy Management Strategy For Plug-in Hybrid Electric Vehicle

Plug-in Hybrid Electric Vehicle(PHEV)contains two power sources,engine and motor,the large capacity batteries which empower motor have the ability to store energy from the electrical grid.Therefore,PHEV has the exhausted gas contamination and energy efficient benefit of Hybrid Electric Vehicle(HEV)and solve the problem of “range anxiety” of Electric Vehicle(EV).The function of energy management strategy for PHEVs is the optimization of distributing the fuel and electric energy,which is the key influence factor of improving the fuel economy.However,the current energy management strategy cannot react to the dynamic driving cycle in the future and thus have a bad real-time performance.To address this problem,an instantaneous optimization energy management strategy based on adaptive driving range and battery SOC is developed,which effectively improves the disadvantage of rule-based strategy having the bad adaptation to driving range.This paper is based upon the project on the improvement of fuel economy by means of adaptive driving range-based energy management strategy for a single-shaft parallel PHEV.The main research contents are as follows:(1)Study on rule-based energy management strategy.Based on the fact that a PHEV can get electricity from electric grid,as a result,PHEV can work in 2 stages,Charge Depleting(CD)stage and Charge Sustaining(CS)stage based on battery SOC,thus a rule-based CD/CS energy management strategy is developed;Simulation analysis on the fuel consumption and running character of components concludes that the vehicle is operated under the CD mode for full-time driving range could have a better fuel economy performance;by controlling the logic threshold in the CD/CS energy management strategy to make the PHEV can be operated in the CD condition for full-time drive range based on the dynamic driving cycles in the future.Through simulation analysis,get the conclusion that rule-based adaptive CD/CS strategy is sensitive to the dynamic driving cycles.(2)Study on equivalent consumption minimization strategy.In view of the problem that the rule-based CD/CS strategy is less adaptable to dynamic driving cycles,the equivalent fuel consumption minimization strategy(ECMS)is developed to replace the CD-phase driving strategy in the vehicle energy management strategy to improve the drawback of rule-based.The relationship between the initial SOC of the battery and the mileage equivalent factor in the ECMS is studied.The simulation result shows a strong correlation between the electrical equivalent factor and,the initial SOC and the mileage of the vehicle.(3)Study on adaptive equivalent fuel consumption minimum strategy.In this paper,the adaptive equivalent fuel consumption minimum strategy(AECMS)is developed and the genetic algorithm is established to solve the problem that the equivalent factor of ECMS cannot adaptively change when the initial SOC and/or driving mileage of the battery change.Specifically,the MAP,the equivalent of the oil and electricity equivalence factor changes with the initial SOC of the battery and mileage,is created based on genetic algorithm to figure out the adaptive problem of ECMS to the initial battery SOC and drive range.(4)Model building and off-line simulation verification.In order to verify the validity and superiority of the AECMS strategy developed in this paper,the simulation model of AVL/Cruise and Matlab/Simulink is set up,in which,the AECMS strategy,CD/CS strategy and ECMS strategy are simulated and analyzed.The simulation result shows that the fuel consumption developed by the AECMS strategy is close to the ECMS strategy.Compared with the CD/CS strategy,the fuel consumption is redacted by 6.73 ~ 8.52%,which achieves the goal of fuel economy improvement for PHEV.