Adaptive Dual Closed Loop Speed Control with Throttle Valve Dynamics for Natural Gas Engine in Range-Extended Electric Vehicles

This study presents an adaptive dual closed-loop speed control strategy for the natural gas engine used in a range extender to improve the robustness against parameter uncertainties, unmodeled dynamics and unknown disturbance. Compared to existing methods, this strategy takes into account the influence of the throttle valve dynamics on the intake airflow in the design of the inner-loop intake pressure controller, which is strongly nonlinear, and considers the inaccuracy of the output torque as well as unknown disturbance in the outer-loop speed controller design, which is more practical. Furthermore, the controller is incorporated with an adaptive strategy to overcome the uncertainty of parameters using the information of the engine speed and the intake pressure. Theoretical analysis indicates that this strategy can meet the demands of the wide range speed regulation of the range extender engine without knowing the specific values of the engine parameters. Moreover, the capability of the proposed controller to preserve the performance in the presence of disturbance in various working conditions is evaluated by co-simulation on the platform of Matlab/Simulink with GTpower and experiments on a range extender.