Robust coordinated control for hybrid electric bus with single-shaft parallel hybrid powertrain

The efficient coupling driving control is a key technique that affects both the fuel economy and drivability of the hybrid electric bus (HEB). However, the uncertainties resulting from the complex driving condition and the powertrain would affect the control performance. To solve this problem, this study proposes a novel control approach, which is elaborately integrated with multi-controllers under the consideration of properties of the city-bus-route and the hybrid powertrain configuration. First, a torque split strategy with the automated mechanical transmission (AMT) gear-shifting strategy is employed to adapt the driving intention quantified by fuzzy logic. Then the coordinated control mechanism is constructed through utilising the electric machine (EM) to compensate the response deviation of engine torque, meanwhile a robust controller is designed to withstand parameter perturbation and external disturbance existing in EM. Simulation results show that the operating points of the engine and EM are adjusted into the high-efficiency areas with the assistance of AMT gear-shifting, and the EM torque tracking performance especially when parameter perturbation and external disturbance appear. Moreover, the strategy adaptively distributed the driving torque in the predefined working modes for different driver's intentions. Thus, the efficient coupling driving of HEB might be implemented by the proposed method.