Lyapunov controller design for a fuel cell electric vehicle powered by a three-level floating capacitor boost converter

Abstract

Electric vehicles (EVs) have undergone considerable progress facilitated by the adoption of contemporary technologies, such as innovative energy sources like the fuel cell (FC) in conjunction with novel power converter architectures. In this context, this work addresses the problem of controlling a three-level flying capacitor boost converter (FCBC) powered by a fuel cell. The converter is linked at its output to an impedance modelling the DC/AC converter and a brushless motor integrated into an FC-EV. Variations in load demand and power provided by the fuel cell are an issue to be considered, alongside voltage balancing, which involves maintaining balanced voltages between flying capacitors, as an imbalance can lead to uneven component voltage and reduced converter efficiency. To solve these issues, a nonlinear controller is developed making use of the Lyapunov approach which ensures the proper operation of the system by continuously adjusting control actions based on the system dynamics. Indeed, the regulator comprises three loops: one dedicated to balancing the voltage across the flying capacitor, and two nested loops; The inner loop controls the inductor current, while the outer loop regulates the output voltage.