The Research Of Dynamic Control During Mode-switches For PHEV

Hybrid electric vehicles are becoming the trend of the development of the automotiveindustry, and have achieved a breakthrough in the market. In hybrid system, the twosources of power need to switch energy management and drive mode according to thedriving traffic. Owing to the different dynamic response characteristics of the engine andthe motor, using the target torque to control the total demand torque according to theirrespective characteristics, this may lead to the power interruption and the torqueoscillation in the process of vehicle running mode switching. This paper studies thedynamic coordination control of the output torque of the engine and the motor in theprocess of operation mode switch, the purpose is to avoid electrical shock caused by theexploding load, hoping to keep the vehicle running smoothly and fast comfort in theprocess of mode switching transition.In this paper, modeling the dynamics theoretical of the parallel hybrid power system,the modeling process is based on the dynamic process of the internal combustion engine,establishing the mean value model of high precision of engine and the direct torque modelof the motor. Aiming at how to realize the key technology of the dynamic coordinatedcontrol algorithm-engine torque online estimate, four kinds of algorithms are put forward:by comparing the principle of fewer parameters, to make the average estimation algorithmof engine as the engine torque online estimation algorithm.Parallel hybrid system from driven by pure electric engine to engine involved indriving mode switches has engine speed control problems. The composite fuzzy-PIDcontrol algorithm is proposed, to ensure the quickness and stability of speed adjustment inthe entire process of mode switching. According to the uncertainty that parameter variableof the engine driving traffic, output delay of the torque and external disturbance, a hybridcontrol method based on LMI is proposed, to make sure the deviation of the engine speedis in the allowed range, and the system has suppression interference performance.The hybrid electric vehicle simulation model is based on the MATLAB/SIMULINKplatform, to make simulation experiment on the dynamic control of torque of the engine into the drive system, the engine quit drive state and motor power compensationrespectively. Experiments show that in the process of three kinds of state switch, dynamictorque coordination control strategy can guarantee dynamic aggregate demand of thetransmission remains the same on the state transition process. Meet the smoothness andcomfort requirements of power transfer in the process of transformation.