Reasearch On Fuzzy Control Strategy Of Parallel Hybrid Electric Vehicle

With automobiles entering millions of households,the drawbacks of traditional fuel-fired automobiles are becoming more and more obvious,accompanied by unbalanced supply and demand of fossil energy and serious pollution of ecological environment,and therefore,one of the tasks of promoting energy conservation and environmental protection in today’s society is to develop new energy vehicles.Hybrid electric vehicles,as a common application in new energy vehicles,have good control quality and application prospects in energy conversion,and have gradually become a research hotspotin recent years.There are two or more power sources in hybrid electric vehicles,and the energy distribution between the power sources is determined by the control strategy.The more advanced the control strategy,the larger the amount of calculations and experimental data required,which requires better accuracy and ease of balance control.In the traditional control strategy,although the fuel economy and emission problems have been well solved,the SOC(state of charge)drops rapidly,and it is difficult to establish an accurate model of the controlled object.In the fuzzy control strategy,the control can be formulated according to the engineering experience.In the fuzzy control strategy,the control rules can be formulated according to the engineering experience,the input quantity can be fuzzified,and the precise output can be obtained by processing the database,which guarantees the fuel economy and emission as well as the control accuracy.On this basis,this thesis takes a parallel hybrid electric vehicle as an example.The specific research contents are as follows:Firstly,the main components of the vehicle are modeled,including the engine model,motor model,battery model,powertrain model,driver model,etc.,andthe whole vehicle model is simulated in CRUISE software.Secondly,the operating conditions of the vehicle are divided into different modes such as pure motor drive,engine drive,driving charge,brake,parallel hybrid,etc.,the switching logic is designed by using MATLAB / Stateflow,and the two strategies are used for joint simulation under NEDC(New European Driving Cycle)standard.Finally,by observing and comparing the effect of torque distribution control,it is concluded that the introduction of fuzzy controller can not only improve the fuel efficiency of the engine,but also keep the SOC within a reasonable range during the whole driving process,which verifies the practical significance of the fuzzy control strategy.