Adaptive Integral Sliding Mode Control for PEM Fuel Cell Power Conversion With Fixed Time Approach

This paper addresses the challenge of output voltage regulation in DC-DC boost converters used in proton exchange membrane (PEM) fuel cell applications, where uncertainties in load resistance and input voltage can significantly degrade output performance. To overcome these challenges, a novel fixed-time (FxT) adaptive integral sliding mode control (AISMC) strategy is proposed. The key advantage of the proposed controller lies in its adaptive gain design, which eliminates the need for prior knowledge of disturbance bounds. This feature, combined with the ISMC framework, ensures robust and practical fixed-time convergence of all closed-loop system states. Specifically, both the sliding surface and associated system states converge to a neighborhood of zero within a fixed time, independent of initial conditions. A rigorous Lyapunov-based analysis is provided to establish the practical fixed-time stability of the system. The controller's effectiveness is demonstrated through MATLAB simulations and validated experimentally on a hardware prototype. The performance of the proposed FxT-AISMC is also compared against an existing finite-time ISMC. Simulation and experimental results confirm that the proposed method achieves faster convergence, reduced overshoot, lower chattering, improved robustness against voltage and load disturbances, and superior error performance metrics.