Simulation Study On System Modeling & Torque By Dynamic Control For Parallel Hybrid Electric Vehicle

The crisis of energy and environment in the earth become worse, which hence flourish the industry of Electric Vehicle (EV) again. The researches on the Parallel Hybrid Electric Vehicle (PHEV) greatly promote the development of the EV industry.The characteristic and the general key technologies have been introduced in the paper firstly, and then the characteristic and the sort of the PHEV. It pointed out that the technology of modeling and simulation was essential to study on the EV, and the energy control strategy of PHEV was the key which affects the performance of the PHEV. The system modeling of PHEV has been determined as the study object of this paper, also the strategy of torque by dynamic control which took effect during the course of mode switching of parallel hybrid system.Based on the software platform of MATLAB/Simulink, the major simulation model of the certain PHEV dynamic system and the transmission system have been established by the way of describing and look-up table, such as the gasoline engine, the electric motor and the gearbox, and so on. The structure of the multi-energy powertrain control system of the PHEV has been also determined. It provided the simulation environment for design and testing the control strategy of the PHEV.The target torque of the engine and the electric motor in the parallel hybrid powertrain have been preassignment by the method of logic threshold control on stable state to insure that engine could operate in high efficiency. The working pattern of the hybrid system and the work attribute of the engine and the electric motor have been all analyzed, and the conclusion that the torque should be controlled in dynamic state. And then, the control strategy which based on torque by dynamic control for the PHEV has been designed, and also the multi-energy control system. Finally, the simulation model of the PHEV has been established.The simulation model of the PHEV only exclude the strategy of torque by dynamic control has been certified correct and valid with the New European Driving Cycle (NEDC). The vehicle simulation model has been simulated with (or without) the strategy of torque by dynamic control by 5 certain operating conditions during the course of the operating modes of hybrid powertrain switching and 2 kinds of whole operating conditions of acceleration and deceleration. The comparative analysis confirmed that the strategy of torque by dynamic control could make use of the advantage that electric motor response to the signal of torque demand rapidly to make up for the shortcoming of the engine response to the signa of torque demand slowly . The strategy insured that the torque output by hybrid powertrain could accord with the driver's torque demand, and the strategy also guaranteed that the torque transmission of hybrid powertrain was stable.