Powertrain Simulation Research Of Hybrid Electric Vehicle

As one of the main products of new energy vehicles,the energy saving effect of hybrid electric vehicle(HEV)is significant.It is the competitive center in domestic and international automobile industry.The development of control strategy is the key technology to develop HEV.A reasonable control strategy can play the all advantages of HEV,optimizing fuel economy and improving driving performance.In this paper,the different structure forms of series HEV,parallel HEV and series-parallel HEV power system are analyzed in detail,the working mode and the characteristics of energy flow in different modes are also discussed.The vehicle model,engine model,motor model,generator model,battery model,clutch model and other key components of the power system model are built based on MATLAB/Simulink.According to the structure of different types of HEV,the key sub models are combined to build the corresponding component models.Based on the analysis of the energy flow of the HEV power system with different structures,the control strategy of the single-axle parallel HEV and series-parallel HEV power system are designed.The control strategy is torque distribution control strategy based on logic gate.The distribution rules of the drive torque and the brake torque are analyzed in detail.Finally,based on the component model,the system control model is established,and the models of singleaxle parallel HEV and series-parallel HEV are completed.The simulation model is built to verify the performance of the single-axle parallel HEV and series-parallel HEV.It can be seen from the simulation results that the model can achieve the expected operating mode,and the torque distribution in each working mode and the change of state of charge(SOC)are in accordance with the torque distribution rules.The simulation results prove the correctness of the model and the effectiveness of the control strategy.Finally,based on the driving cycle of Xi'an,the series-parallel HEV power system model is simulated.The simulation results are in good agreement with the expected,which verifies the validity of the model and the feasibility of the control strategy.The changes of SOC and gas consumption in the whole operation process are obtained,which provides the index for the further optimization of the control strategy,and has certain significance to the development of the control strategy in the design process of the HEV.