Design And Optimization Of Energy Management Strategy For Fuel Cell Hybrid Electric Vehicle

FCHEV requires a number of energy sources to work together,how to arrange each energy source in what time "output" and "how much" is important to improve the vehicle fuel(hydrogen fuel)economic performance and power performance,as well as extend the lifespan of power battery.Aiming at the problem of energy management of FCHEV,based on the modeling of its driving system,this paper analyzes the resistance of the vehicle and the working characteristics of energy sources,and designs the energy management strategy based on the adaptive model prediction control method and hierarchical method.Firstly,the hierarchical energy management strategy is proposed.Through analyzing the changing rule of battery internal resistance and the working efficiency of fuel cell,the output power of fuel cell is designed according to the demand power.On this basis,the working characteristics of batteries and ultracapacitors are analyzed,the power output of batteries and ultracapacitors is designed,and the management problem of three energy sources is transformed into the management problem of two pairs of dual energy sources.Secondly,the adaptive model prediction energy management strategy is proposed for hybrid electric vehicle equipped with battery and supercapacitor.By analyzing the working characteristics of battery and supercapacitor,the reference value of battery power and the supercapacitor SOC is designed according to the longitudinal dynamics analysis of the vehicle.And considering the constraint conditions of the optimization objective function,the model predictive control method is adopted to allocate the power output of battery and supercapacitor.Thirdly,an adaptive equivalent consumption minimization strategy is proposed.By analyzing the working characteristic of fuel cell,battery and supercapacitor,the demand power is divided into peak power and smooth power by using the low pass filter.Supercapacitor provides the peak power,and in order to reduce the hydrogen consumption of fuel cell,the equivalent consumption minimization method is used to allocate the output power between fuel cell and battery.Finally,the energy management strategy in this paper is verified in the simulation and experimental environment.The results show that the battery and supercapacitor can relieve the stress on fuel cell under the hierarchical energy management strategy,and the fuel economy is improved by 4.37% compared with the advisor’s strategy.Under the adaptive model predictive control energy management strategy,the output power of battery is low and stable,and the supercapacitor SOC is maintained in a proper value,which further extends the battery lifespan and improves the power performance of vehicle compared with the model predictive control strategy.Under the adaptive equivalent consumption minimization strategy,compared with the strategy of equivalent consumption minimization,the output power of fuel cell and battery is low and stable,hydrogen fuel consumption is low,and supercapacitor SOC is maintained in a proper value.