Electromechanical coupling driving control for single-shaft parallel hybrid powertrain

The single-shaft parallel hybrid powertrain with the automatic mechanical transmission (AMT) is an efficient hybrid driving system in the hybrid electric bus (HEB), while the electromechanical coupling driving control becomes a complicated question to find a transient optimal control method to distribute the power between the engine and the electric machine (EM). This paper proposes an innovative control method to deal with the complicated transient coupling driving process of the electromechanical coupling driving system, considering the accelerating condition and the cruising condition mostly in the city driving cycle of HEB. The EM might be operated at driving mode or generating mode to assist the diesel engine to work in its high-efficiency area. Therefore, the adaptive torque tracking controller has been brought forward to ensure that the EM implements the demand torque as well as compensate the torque fluctuation of diesel engine. The d-q axis mathematical model and back stepping method are employed to deduce the adaptive controller and its adaptive laws. Simulation results demonstrate that the proposed control scheme can make the output torque of two power sources respond rapidly to the demand torque from the powertrain in the given driving condition. The proposed method could be adopted in the real control of HEB to improve the efficiency of the hybrid driving system.