The Research Of Energy Control Strategy For Plug-in Hybrid Electric Vehicles

The invention of the car brings great civilization to human society, it is changingpeople’s work, life and ways of thinking, in today’s society has become one of the mostimportant means of transport, the automobile industry has become a pillar industry ofnational economy. But at the same time, the rapid development of automobile industry hasbrought tremendous negative impact, such as the increasing depletion of oil resources, alarge amount of waste emissions, etc. With the increasing of car ownership, the car bringsthe negative impact is increasingly prominent, energy conservation and emissions reductionand climate change has become a common human challenges.In recent years, energy conservation and environmental protection, the concept ofgreen travel were widely recognized by the international community. Hybrid cars havebecome the focus of transportation development and the focus of the research anddevelopment of automobile industry. Plug-in hybrid cars combine the advantages oftraditional cars and electric vehicles, showing its good practicability and environmentalprotection.Energy control strategy formulation is the key to success of a plug-in hybrid car design,is the core of plug-in hybrid technology. Good energy control strategy can be a reasonableallocation of vehicles when driving demand energy distribution between engine and motor,in order to make sure its good power performance, fuel economy and emissions. Therefore,the study of plug-in hybrid electric vehicle, energy control strategy research is crucial.Energy control strategy based on logic threshold method, because of its simple ideas,code, high conversion rate, easy to implement and can obtain good control effect whendriving, and become the most widely used hybrid control strategy. Logic thresholdparameters are usually preset and fixed. This kind of control strategy often can onlyguarantee that the output characteristics of the engine e more efficient range, and can’talways guarantee to achieve the efficiency optimization of engine. For different roadconditions and vehicle parameters change, vehicle at the time of the poor ability can not toadapt. So it is necessary to do further analysis and research in the control strategy.This article main research contents are as follows：(1)Motor is one of the main power supply plug-in hybrid car, so you need to do furtheranalysis and research for the working efficiency of the motor, according to the parametersof the motor, to make the best motor optimum efficiency curve. Results showed that themotor of the optimum efficiency curve throughout the entire speed range, with a goodcontrollability. Motor work on optimum efficiency curve can guarantee the efficiency of ahigh value, but different torque and speed requirements, the motor doesn’t always work on the optimum efficiency curve, therefore the motor is made for optimum efficiency range inthis article, as possible to make the motor work in high efficiency range, and also able tomeet the requirements of speed and torque.(2)Engine is another power source for plug-in hybrid car, so copy for motor processing,to make the optimal control curve of engine, and at the same time to make the optimalengine control range.(3)According to the optimal control curve of engine and motor, optimal control rangeand optimum efficiency curve and the best efficiency of interval, the demand for differentbattery and torque constraint conditions to work out the control strategy of the optimalcontrol range. And in the matlab/simulink environment, to make the control strategy models.The modeling results embedded the hybrid electric vehicle simulation softwareADVISOR2002, through the simulation, a new control strategy in terms of fuel economyand emissions, has greatly improvement. Genetic algorithm was applied, the engine of theboundary of the optimum efficiency range and battery charged state of soc (state of charge)to do further optimization. After optimization, the vehicle’s fuel economy and emissionshave been further improved.(4)Motor is not only used to drive the car in addition to the thought, can also be usedto brake. Therefore, on the basis of analyzing the braking principle to formulate the controlstrategy of regenerative braking energy. Strategies according to different braking strengthand battery soc, reasonable distribution of the braking force in the ratio between frictionbraking and regenerative braking. Battery life is also one of the reasons that restrict thedevelopment of hybrid cars. The safety of the vehicle also includes a battery life of security.Finally, the use of control strategy to fuzzy control principle, further restrict the batteryanti-overcharge resistant performance. Through the simulation, prevent overcharge abilityhas been greatly improved.In this paper, the control strategy of the research has carried on the certain analysis andthe simulation experiment, it can provide certain help for subsequent study and contributeto the development of plug-in hybrid render a bit. This also is what purpose of this study.