Research On Electric Drive System Of Parallel Hybrid Bus

Electric drive system is an important part of the parallel hybrid electricvehicle (PHEV), with which the internal combustion engine cooperates todrive vehicle. Based on the drive cycle and the characteristic of electric drivesystem, the parameters of major components in electric drive system can bechosen appropriately, the control of electric drive system can be optimized aswell, which improve the vehicle economy of PHEV.The thesis introduces the configuration of the electric drive system ofPHEV. To focus on the battery system, various subsystems and workingprinciple of battery system are described, the hardware architecture andsoftware process of the battery management system are introduced in detail.According to necessary experiments of lithium-ion battery, the author getsrelationship between the state of charge (SOC) and the battery life as well asbattery internal resistance. There’re also experiments on battery system andmotor system performances about environmental suitability. At the same time,with necessary real road tests, functions of battary system are inspected andverified.Based on the parameters of the target vehicle and typical urban drivecycle in China, the vehicle needs of motor and the battery are calculated andthe way how parameters of motor and battery influence the vehicle economyis analyzed. With the emulation tool of MATLAB/Simulink, the forwardPHEV simulation model is established, of which the parameters and controlstrategy are mainly the same as the target vehicle. The vehicle model providesmuch convenience in the researching on how the main parameters’ change ofthe motor and battery influence on vehicle economy in electric drive system.Using the rapid prototyping methods and the same vehicle controlstrategy as that in simulation model, the bench experiments about how themain parameters of electric drive system influence on vehicle economy are carried out. The test and simulation results are compared so as to summarizethe principles that how electric drive system impact on the fuel economic ofPHEV. Taking battery character into consideration, some optimizing measuresfor PHEV to improve the vehicle economy are supplied. Finally, the thesisconcludes several principles and usual steps on choosing the main parametersof electric drive system of PHEV.