Powertrain parameters and control strategy optimization of a novel master-slave electric-hydraulic hybrid vehicle

ABSTRACTThe electric-hydraulic hybrid vehicle (EHHV) is an important research area of hybrid electric vehicles (HEV), which provides a competitive project compared to other hybrid technologies. This paper conducts comprehensive research on a master-slave electric-hydraulic hybrid vehicle (MSEHHV). After an integrated driving cycle, the battery state of charge (SOC) values for MSEHHV and electric vehicle (EV) are 44.65% and 38.27%. The economy of the MSEHHV is verified, which is obviously superior to the EV. To further explore the energy conservation potential of the MSEHHV, the research proposes a cooperative optimization method of powertrain parameters and control strategy. Specifically, the optimization objective is to improve SOC. The response surface method (RSM) fits the functional relation between design variables and optimization objective. An optimization model is constructed based on the response surface model. Ultimately, the particle swarm optimization (PSO) algorithm is used for the optimal solution to obtain the optimal parameter combination. To evaluate the adaptability of the method, the performance of three models in the actual driving cycle is compared. Simulation results suggest that the energy consumption of the optimized MSEHHV is 33.41% and 6.33% lower than that of EV and initial MSEHHV. The research provides a valuable reference for the optimal design of electric-hydraulic hybrid technology.KEYWORDS: hybrid electric vehicleelectric-hydraulicparameter optimizationpowertrain componentcontrol strategy Nomenclature EV=HPAHEV=Hybrid electric vehicleEHHV=Electric-hydraulic hybrid vehicleMSEHHV=Master-slave electric-hydraulic hybrid vehicleSOC=State of chargeRSM=Response surface methodPSO=Particle swarm optimization algorithmLHS=Latin hypercube samplingHD=Hydraulic drive modeED=Electric drive modeE-HD=Electric-hydraulic drive modeHRB=Hydraulic regenerative braking modeERB=Electric regenerative braking modeVCU=Vehicle control unitHPA=The high-pressure accumulatorLPA=The low-pressure accumulatorHP/M=Hydraulic pump/motoru=The velocity threshold10-15=Japanese 10-15 mode cycleHWFET=Highway fuel economy testUS06=The US06 supplemental federal test procedureSC03=The SC03 supplemental federal test procedureNEDC=New European driving cycleu1=The low-velocity thresholdu2=The high-velocity thresholdpL=The lowest working pressure of the LPApH=The highest working pressure of the HPAAcknowledgementsThe project is supported partly by the National Natural Science Foundation of China (No. 52075278), and the Municipal Livelihood Science and Technology Project of Qingdao (No. 19-6-1-92-nsh).Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the National Natural Science Foundation of China [52107220]; Municipal Livelihood Science and Technology Project of Qingdao [19-6-1-92-nsh].Notes on contributorsQingxiao JiaQingxiao Jia is a degree graduate student at the College of Mechanical and Electrical Engineering, Qingdao University. His main research interests are parameter matching, energy management strategy design and system optimization for new hybrid vehicles.Caihong ZhangCaihong Zhang is a lecturer at the College of Automation, Qingdao University. She specializes in control theory and control engineering.Hongxin ZhangHongxin Zhang is the deputy dean and professor of the College of Mechanical and Electrical Engineering, Qingdao University. He mainly conducts the design and simulation of new power transmission technology for vehicles.Zhen ZhangZhen Zhang is a degree graduate student at the College of Mechanical and Electrical Engineering, Qingdao University. His research focus on vehicle control systems and vehicle energy management strategy.Hao ChenHao Chen is a degree graduate student at the College of Mechanical and Electrical Engineering, Qingdao University. His research direction is the performance prediction of a new type of electro-hydraulic hybrid electric vehicle.