Study On Energy Management Strategy Of Series Plug-In Hybrid Electric Vehicle Based On Dynamic Programming

Plug-in hybrid electric vehicles (PHEV) can both use electric energy to take the place of fuel and use fuel if needed. How to take full advantage of the low-cost electric energy from power grid and reduce vehicles' fuel consumption and emission has become a hotspot and difficulty at study on energy management strategy of plug-in hybrid electric vehicles now. The research and simulations of series PHEV powertrains through dynamic programming (DP) are the main emphasis of this thesis.This paper has illustrated research status about control strategies used for PHEVs and research significance. The paper analysed the advantages of series structure referenced Futian bus BJ6123SHEVCA and determined the plug-in hybrid bus using series structure.The powertrain parameters of a series PHEV being studied have a matching calculation. The mathematical model of optimal control problem has been established. Using the discrete DP algorithm to solve the optimization problem. With equivalent fuel optimum and power system cost optimum as the objective function to write MATLAB programs.Energy control effects of PHEV have been got based on DP. The simulations have integrated program with three kinds of drive cycles:US06, UDDS and ECE. Simulation results show that DP algorithm is very suitable for this kind of nonlinear optimal control problem with constraints of PHEV powertrain and can achieve global optimal. Fuel economy of DP strategy is better than that of power following strategy, which can be reduced about 17.35%.The research achievements of this paper can provide the theory basis and supporting data for designing control strategy of PHEV, which has a certain theoretical and practical value.