The Research On Energy Management Strategy For Plug-in Hybrid Electric Buses Based On Stochastic Predictive Control

Recently,with the increasing number of automobile,the growing depletion of non-renewable resources and the increasingly grim environmental problem,the new-energy automobile has been developed quickly.Specially,in the field of public transportation,the hybrid electric vehicle(HEV)has reduced the energy consumption and emissions greatly,which provides a guarantee for the reducing of urban haze and is recognized widely.For the studied automated mechanical transmission(AMT)based single-shaft parallel hybrid powertrain,the complex multiple subsystem,nonlinear characteristics,multiple operation modes and the uncertainty in the running process of this system should be considered.Therefore,how to realize the high efficiency control strategy for HEV is still a challenging technology for improving the fuel economy and transmission efficiency.For this problem,the main work of this paper is presented as follows:First,the forward vehicle model is established,which is based on the studied single-shaft parallel hybrid electric bus(PHEB).And there mainly are four parts,the model of driver,model of controllers,model of actuators and model of vehicle dynamics.Then,combined with characteristics of PHEB and its driving conditions,two kinds of energy management strategies,which are used for some unsolved problems of PHEB,are proposed:1 Considering the uncertainty of drivers which is caused by the complex and changeable urban city bus cycle,combined with plenty of real-world running data,the statistical method is adopted to predict the driving behaviors.Meanwhile,considering that the statistics and repeatability of the city bus route,the energy management strategy based on predictive control is more possible for getting optimal solutions.Therefore,combining the characteristics of the studied system,the driving cycle and the driving behaviors,the driving-behavior-aware stochastic model predictive control(SMPC)for plug-in hybrid electric buses is proposed,which is a kind of near optimal energy management strategy.2 The AMT based SPHEB rely on the combination of multiple operation modes and different gears of AMT to get better fuel economy and improve the working efficiency of engine and electric motor.However,the mode transitions between different modes can result in extra fuel consumption and influence the drivability of vehicle strictly.Therefore,it is still an urgent problem to reduce the unnecessary mode transitions and realize good fuel economy.For this problem,the multi-objective SMPC based system control architecture for PHEB to realize lower fuel consumption and less mode transitions.Finally,this paper studied stochastic predictive control based energy management strategy for PHEB,and the driving-behavior-aware MSMPC and multiple-objective SMPC are proposed.Via the analysis of simulation results,it can be found that the proposed control strategies can be effective to realize the collaborative optimization of fuel economy and frequent switching between multiple operation modes.