Research On The Control Strategy For The Four-wheel-drive Plug-in Hybrid Electric Vehicle

Four-wheel-drive plug-in hybrid electric vehicle not only has good fuel economy andemissions, but also has superior dynamical performance, especially when it drives onlow-traction conditions, such as off-road or on snow or ice, this feature reflects moreobvious. In order to give full play to the advantages of four-wheel-drive plug-in hybridelectric vehicles, one of the core issues control strategy is researched and analyzed detailedlyand in depth. In this paper, according to the idea of "Modeling-Design Control Strategy-Simulation" to research the engine optimal energy management control strategy and fulloperation mode traction control strategy. The purpose is to obtain a good fuel economy ofthe vehicle while having a good stability and traction performance. The main work is asfollows:(1) Fourteen degrees of freedom model and tire model were built in Matlab/simulink.And the simulation models for components of powertrain, such as engine, motor, batterywere established on the LMS Imagine.Lab AMESim simulation platform. Then fully testswere implemented to guarantee that the models can properly reflect the system features offour-wheel-drive plug-in hybrid vehicles.(2)According to the characteristics of four-wheel-drive plug-in hybrid electric vehicles,the engine optimal energy management control strategy was designed based on the idea ofengine optimal and logic threshold control method, to divide the operation modes ofpowertrain detailedly. Then based on PID and logical threshold control method, the fulloperation mode traction control strategy was designed.(3)Finally utilize the co-simulation between Matlab/simulink and AMESim to simulateand verify the two of proposed control strategies. Firstly the energy management controlstrategy was tested on the driving cycle of NEDC, and the results show that the strategy canimprove vehicle fuel economy while it can be able to meet the vehicle dynamic requirements.Then simulation was implemented to test the full operation mode traction control strategy onthe typical driving cycle. It turned out that the strategy can meet the control requirementsthat no matter what kind of road the vehicles moving on and what kind of mode thepowertrain operation on, the traction control system can be able to obtain good control of the vehicle stability and traction performance.