Research On Mode-shift Coordinated Control Of Parallel-series Hybrid Electric Vehicle

Energy is becoming shortage,and environmental pollution is becoming more and more serious,which already have become two major challenges for sustainable development of the auto industry.However,bottlenecks throughout the pure electric vehicle means it cannot be popularized in the short term,so the development of hybrid electric vehicle(HEV)has become the main stream of the new energy vehicle.Energy management strategy is the key technology of energy-saving and emission reduction for HEV.Among then,mode switch coordination control realizes that the HEV can effectively allocate and optimize traveling efficiency in multiple power sources.During the mode-switch process,the coordinated control of the parts of drive system can improve vehicle stability,comfort,economy,and power performance at runtime.Therefore,the research of mode switch coordination control has important practical significance in the hybrid vehicle industry development.This paper works through a parallel-series hybrid electric vehicle(PSHEV)which from a new energy vehicle company in Ganzhou city.Devising a set of motor optimal control strategy based on the real-time compensating torque,so that the engine can work in the high efficiency area when the vehicle is switched to the engine working model.When the vehicle required low torque,the engine is turn off,and when required high torque,the engine runs at high efficiency area.The difference between the required torque of the vehicle and the engine torque is provided by the motor.It makes the engine working time as little as possible,the working range controlled in the high efficiency area,when the HEV is running.At the same time,it realizes the energy allocation optimization of the vehicle,and improves the driving performance.As the internal-combustion engine,the engine is the main source of harmful gas emissions,so this strategy also reduces the fuel consumption and exhaust emissions during operation.This research is focus on following area:Introducing the background and significance of the research;Analyzing three kinds of the HEV systems: SHEV(Series Hybrid Electric Vehicle),PHEV(Parallel Hybrid Electric Vehicle),and PSHEV,and drawing their own characteristics;Focusing on the driving model of the PSHEV and corresponding energy control strategy.The article builds the mathematical model of the PSHEV powertrain components.Through analyzing and comparing the advantages and disadvantages of the theoreticalmodeling method and the experimental modeling method,finally select the engine average model.The model consists of three sub-models: air model,fuel-film model,dynamic model.This article establishes vehicle dynamics,clutch,motor and a series of models by analyzing the structure of power components,and according to the mechanics.Meanwhile,through the simulation experiment,analytical data to determine whether the model have the accuracy and practicability,which can provide the model basis for the vehicle performance simulation experiment and mode-switch coordination control strategy optimization.This article based on logic threshold control strategy(component operative mode control rules;driving torque distribution rules;regenerative braking torque rules)and optimize a suit of mode-switch coordination control strategy for use in PSHEV.It nests the control strategy model which built in MATLAB/SIMULINK and the vehicle model which built in AVL-Cruise,then through the joint simulation to validate the effectiveness and rationality of the proposed mode-switch coordination control strategy.To achieve the torque coordinated control strategy during mode switching,this article designs the electronic throttle control strategy,the establishes the electronic throttle model,and creates the inverse model intelligent controller.On the base of improving the engine torque output response speed,this strategy also highlights the generator toque compensation effect.Finally,it achieves optimization of engine torque output.The NEDC simulation result shows that the engine torque ripple is greatly reduced by using torque coordinated control and the vehicle longitudinal impact is optimized.Finally,when the PSHEV is in the process of switching mode,the power can be switched smoothly and the driving performance is improved.