Study On Integrated Energy Management Strategy Of PHEV Considering Energy Consumption Of Cooling System

Plug-in hybrid electric vehicle(PHEV)has a broad development prospect with its advantages of both long endurance mileage and significant fuel economy in the context of energy crisis,environmental protection and national strategy.The development of efficient and energy-saving energy management technology is an important way to improve the fuel economy of PHEV.The energy consumption of cooling system for multiple power sources in PHEV,as an important factor affecting the comprehensive energy consumption of the vehicle,has not been fully valued.In this paper,a new type of dual-motor planetary coupling PHEV is taken as the research object,and the comprehensive energy management strategy of PHEV considering the energy consumption of cooling system is studied.Firstly,a new type of dual-motor planetary coupling PHEV power transmission system and its cooling system model are built.The structure of hybrid power system is introduced and its power flow is analyzed,the working mode of the system is combed,and the models of the components in power system is built.Then the comprehensive cooling system architecture for engine and motors is built.According to the characteristics of high and low temperature circuit and the maximum cooling demand of each driving component,the cooling system parameter matching calculation is carried out,and the cooling system model is built.Secondly,according to the different cooling requirements of the high and low temperature circuit,the overall control scheme of the cooling system is developed and the optimal controller of the electric fan and the electronic pump is designed.Due to the frequent switching of working mode and the drastic change of driving component working power in PHEV,it is difficult to control the temperature fluctuation of coolant accurately and the energy consumption of the system is large.An optimization controller based on Lyapunov is built to optimize the real-time control of electric fan and electronic pump.The results show that the designed controller makes the working temperature of the coolant stable in New European Driving Cycle(NEDC).Compared with the traditional threshold rule control,the equivalent fuel consumption of the cooling system at 20~°C and 40~°C ambient temperature is reduced by 37.5%and 29.7%respectively.The optimal control of cooling system energy consumption is achieved.Then,the integrated energy management strategy of the whole vehicle considering the energy consumption of the cooling system is designed.Combined with the motion characteristics of the dual-motor planetary coupling power system,a separate energy management strategy(S-EMS)is designed based on the equivalent consumption minimum strategy(ECMS)where the driving system and the cooling system are independently controlled;further considering the mechanism of different cooling power requirements of power system in different working states,cooling system energy consumption has impact on vehicle energy consumption,as well as the boundary constraints of vehicle power distribution are changed by cooling accessory power requirements,and the integrated energy management strategy(I-EMS)is design for integrated control of driving system and cooling system.Considering the influence of temperature on the efficiency of driving components,the comprehensive penalty factor of temperature and state of chare of battery(SOC)are introduced into I-EMS,and the fuzzy controller is designed to modify penalty factor in real time.The simulation results show that the proposed I-EMS can actively adjust the working state and output torque of the driving components,and further reduce the high heat load and energy consumption of the cooling system on the premise of meeting the driving and cooling power requirements of the vehicle at the same time.Compared with the S-EMS,the I-EMS can further reduce the high heat load and energy consumption of the cooling system on the premise of ensuring the power demand and component stable temperature of the vehicle,and the equivalent fuel consumption per kilometer is reduced by 9.75%and10.73%respectively in NEDC and China Light-duty Vehicle Test Cycle for Passenger Car(CTLC-P).Finally,the hardware-in-the-loop simulation platform is built to further verify the reliability and real-time effectiveness of the designed energy management strategy in the real-time operation environment.The control strategy is developed in Matlab/Simulink,and downloaded to rapidECU rapid prototype controller in real time.The NI real-time simulator runs the whole vehicle AMESim model.The results show that the trend of I-EMS results designed in this paper is consistent with the simulation results,and the reliability and real-time effectiveness of the energy management strategy are verified.