Robust Integral Backstepping Control for Unified Model of Hybrid Electric Vehicles

Exponential decrease in oil and natural gas resources, increasing global warming issues and insufficiency of fossil fuels has shifted the focus to fuel cell hybrid electric vehicles (FHEVs). FHEV model used in this work consists of fuel cell, ultracapacitor and battery. Non-linearities present in the vehicle model dominate because of extreme driving conditions like rough terrains, slippery roads or hilly areas. Behavior of components like energy sources, induction motors and power processing blocks deviate significantly from their normal behavior when driving in highly demanding situations. To tackle these shortcomings, non-linear controllers are preferred because of their efficiency. In literature, different controllers have been proposed for either the energy sources or the induction motor separately, whereas this research work focuses on a unified hybrid electric vehicle (HEV) model to simultaneously control the energy sources and the induction motor. The model used is a complete representation of electric system of FHEV and increases the performance of the vehicle. This unified model provides improved DC bus voltage regulation along with speed tracking when subjected to European extra urban drive cycle (EUDC). In this work, Robust Integral Backstepping and Robust Backstepping controllers have been designed. Lyapunov based analysis ensures the global stability of the system. Performance of proposed controllers is validated in MATLAB/Simulink environment. A comparative analysis is also given to illustrate the importance of the unified model proposed in this work.