Study On The Parametric Design And Control Strategy Of Series-parallel Hybrid Electric Bus

With the development of science and technology and lack of energy, the storage ofpetroleum resources can not meet the growing needs of us. Gradually people put the attention onhybrid electric vehicles. However traffic is increasingly congested, the development of publictraffic is extremely urgent, therefore hybrid electric bus is the preferential develop object inChina. The series-parallel hybrid power system becomes a hot point of the next momentresearch and development of hybrid electric bus because of its energy saving potential andsuperior dynamic performance. The domestic automobile companies are inferior in the research,development and production capacity of the assembly and parts, so they can only choose thedual-motor structure without transmission, which takes the clutch as a power coupling device.This thesis studies the parameter matching and control strategies of the dual-motor structurebus. The main contents of the paper include as following.Consult the progress of the series-parallel hybrid bus domestic and abroad. Matched thepower source parameters of the dual-motor hybrid power system based on the vehicleparameters and design requirements of the traditional bus. Firstly, estimate the maximum powerof the total power of the power system and each power assembly unit under the principle ofdynamic performance requirements and the power requirements of the driving cycle. After that,determine the characteristic parameters of the engine and electric motor under the principle ofhigh efficiency zone matching, and calculate their maximum power to make amendments to thepreliminary estimates. Then, get the characteristic parameters of the battery to meet the powerand energy requirements.Divide the driving strategy into four drive conditions and the braking strategy is dividedinto three braking conditions to make sure that the engine works in the high efficiency zone allthe time. Introduce the determinant conditions and processes of each mode in detail and makein-depth analysis of them.Respectively build the whole vehicle model and control model based on the forwardsimulation software CRUISE and Matlab/Simulink. Simulate the dynamic and economicperformance through the CRUISE dynamic link library, and evaluate the parameter matchingand control strategy. Finally, by the real road tests dynamic performance and fuel consumptionare measured to further demonstrate the correctness and rationality of the parameter matching and control strategy.Analyze the regenerative braking problems and the clutch control problems when modeswitching in the simulation process. Firstly, to the regenerative braking problems, propose theoptimization theory of braking control after the kinetics analysis, simulate with the urbandriving cycle. Verify the rationality and superiority of the optimized regenerative brakingstrategy through the simulation results before and after the optimization. Secondly for clutchcontrol, find out that the switched static control deficiencies in the original strategy and theenormous impact of the transmission system analyze and modify the clutch dynamic processcontrol method, and show the necessity and effectiveness of the clutch dynamic process controlthrough the comparison of the effects of switched static control and dynamic process control.In summary, this paper proposed the dual-motor structure configuration for theseries-parallel hybrid electric bus, matched the parameters of the power system, built andoptimized the control strategy. The correctness and rationality of the matching parameters andcontrol strategy are verified through modeling and simulation tests, the results also show thatpotential of energy saving is tremendous. Research content of this thesis could guide thedevelopment of the dual-motor hybrid bus without transmission.