Research On Energy Management Strategy Of AMT Full Hybrid Electrical Vehicle With Single ISG

Energy management strategy of hybrid electric vehicle (HEV) is one of the keytechnologies to decide the performance of HEV, and a reasonable and effective energymanagement strategy plays an important role in reducing total fuel consumption andemissions, as well as maintaining good dynamic performance. Therefore, research onenergy management strategy of HEV has great theoretical significance and applicationvalue.In this dissertation, aiming at a novel AMT full hybrid electrical vehicle with singleIntegrated Starter Generator (ISG), the working characters of planetary gears andAutomated Manual Transmission (AMT) are investigated to study the energymanagement strategy of the hybrid system. These main researches and conclusions areas followed.①According to the structural features of the HEV powertrain system, the workingfeatures of rotate speed and torque of the planetary gears are deeply researched, and theoperating principle of each mode of the HEV powertrain system is analyzed, theexpressions of rotate speed, torque and power supply power allocation for system outputare deduced. On this basis, the state switch relationship between different operationmodes is obtained.②According to the structural and function features as well as the dynamicproperty index of the HEV, the matching research on relevant parameters of engine, ISG,Ni-MH power batteries, AMT, planetary gears, wet clutches and hydraulic controlsystem has been done. Based on parameters matching of key components, numericalmodels of performance characteristics of engine, ISG and Ni-MH power battery arebuilt by doing bench test. The numerical relationship between duty circle of theproportional valve and engaging pressure of the wet multi-plate clutch is obtained byperformance test of the hydraulic power unit. Based on the above, the dynamic propertyof the hybrid system is analyzed and then the rationality of parameters matching of thepowertrain is verified by analysis of simulation result under typical urban drivingconditions.③Kinetic equations of the HEV under driving modes are established, and theefficiency calculation model of the HEV system under typical driving modes is deducedconsidering the efficiency of engine, ISG, Ni-MH batteries and powertrain system.Considering the performance characteristics of power components (including the engine, ISG motor and nickel-hydrogen batteries) as constraint, efficiency optimization modelsof the system under different driving modes are built to obtain switching law of systemworking modes, shift schedule of AMT and the optimized motoring and generatingtorque of the ISG motor under a given speed and acceleration condition. By meeting therequirement of brake regulations, energy recovering model of the HEV is built. Tomaintain the maximal energy recovering, the control strategies of energy recovering andshift schedule of AMT are proposed considering the vehicle braking strength, brakingforce of ISG, AMT gear and the State of Charge (SOC) of Ni-MH batteries.④According to the limitations existed in the energy management strategy ofhybrid electric vehicle (HEV) under fixed driving cycle condition,20typical cycleconditions which stand for vehicle real driving conditions are chosen from ADVISORsoftware and the key control parameters involved in the energy management strategiesunder each driving cycle are optimized by using particle swarm algorithm aiming at thecomprehensive goal of vehicle total fuel consumption and power battery life, after that,relevant optimized results are saved in database, and then, the dynamic energymanagement strategy of HEV based on the recognition of driving conditions is proposed.Finally, the energy management strategy is simulated under a random driving condition,the simulation results show that the vehicle fuel consumption dropped by10.70%, thepower battery temperature rise and the average effective work current decreased by2.46℃and1.63Arespectively by using dynamic energy management strategycompared with energy management strategy without driving condition recognition.⑤Hardware in the loop simulation test bench of the powertrain of the HEV andreal-time monitoring system of the test bench are developed. Different working modesof HEV such as starting engine in only electric driving condition, charging battery indriving condition, ISG assistance driving and regenerative braking are tested to verifygood control effect of the energy management control strategy in this dissertation.