Research On Control Strategy For A Parallel Hybrid Electric Vehicle

There are two serious problems against the continual development of the automotive industry in the world. One is environmental pollution; the other is deficiency of petroleum resources. Hybrid electric vehicle (HEV) employing two power sources -internal combustion engine (ICE) and electric motor(EM), has been accepted world-widely as one of the most promising methods to solve these two problems. The research of control strategy for the HEV and control technology for the ICE are the core of HEV , so author take them as research object. There are three contents in the investigation:Firstly, a kind of parallel hybrid electric vehicle is chosen as research object. Author carries out a lot of study for the simulation software of HEV—ADVISOR such as batteries's state of charge, the account of fuel consumption, the account of powertrain and the estimate of emission. Subsequently, control model of parallel hybrid electric vehicle was created in simulation software ADVISOR and embeded the model of completed car, which establishes the base for the off-line simulation.Secondly, hybrid electric vehicles improvements in fuel economy and emissions strongly depend on the energy management. After systemic investigating the various control strategies for HEV, a blend energy management control system for a parallel hybrid electric vehicle is presented in this paper. The proposed system incorporates a fuzzy logic scheme to assess the amount of internal combustion engine and motor's torque as well as a charge sustaining scheme to ensure better battery's charge balance during the driving cycle. Computer simulation work and experiment are carried out with simulation software ADVISOR to evaluate the proposed energy management system. It was found that significant improvement of fuel economy and vehicle's drivability could be achieved with emission reduction.Thirdly, in the view of the physical characters of ICE, the mathematic equations about dynamic characteristic of engine's primary subsystems were presented. Under the environment of Matlab/Simulink, a nonlinear simulation model for the engine of the hybrid electric vehicle is built up. A new backstepping sliding mode controller was designed based on the simplified model of engine, and the simulation results show the great improvement of engine control performance, especially to overcome the disturbance(such as the change of load).In conclusion, the work in this thesis is systematic. The research work could expedite the course of the control strategies for HEV. Restricted by condition of experiment, the study for control strategies for HEV only carries out in theory. The research should go deep into the field.