Research On Multi-mode Switch Control Strategy Of HEV With An Integrated Starter Generator

The grand challenges for the automotive industry are two issues of energy crisis and environmental pollution, it is crucial for improving hybrid electric vehicle. The research on working mode selection, switch, torque ripple during working mode switching has important theoretical significance and practical value, to improve the vehicle performance, comfort and energy conservation and emissions reduction under different road conditions.First, propose a full hybrid propulsion ISG-HEV: adopting split hybrid power output method, by controlling the engagement/separation state of four electrically controlled cluches, the power of the engine and two motors can output directly, at the same time, the motor power also can be used as auxiliary power. Then adopt electrical power splitter to distribute the power of the EMG and ISG, and use total power splitter to distribute the power between the engine and electric drive system.Secondly, design the electronic throttle fuzzy sliding mode control strategy to improve the dynamic performance of engine, decrease the torque ripple ISG-HEV when ISG-HEV’s work mode switches due to the engine dynamic response time is long. And on this basis, the ISG motor torque compensates the engine torque control strategy is designed in the work mode that the engine involved in, to optimize the energy distribution, and improve fuel economy and dynamic quality.Thirdly, regarding ISG-HEV work mode switch as switching control problem in the mixed system, design the multi-mode switch control strategy. To reduce the complexity of control algorithm, the ISG-HEV complex control system is divided into two systems, namely, the working mode switch system and the electric driving mode switch system. The first system is torque coordination control between the engine and motors(including the ISG and EMG motors), the second system is between the ISG and EMG motors. Then divide the working modes of two systems, and design control rules to select and switch the working mode.Finally, using the Matlab/Simulink and Advisor software to establish the power system simulation model of the ISG-HEV, then the simulation and comparison analysis of control strategies are made. Simulation results show that the dynamic performance of engine is improved, the operation efficiency of engine is improved to 38.6%, ISG motor can compensate torque and recover energy effectively, and the multi-modeswitch control strategy satisfies the power requirements of ISG-HEV, meanwhile, the speed and torque response ability are all improved.