The PEMFCs are considered to be promising clean energy technology for electric transportation and distributed generation owing to their high efficiencies and low emissions; however, their nonlinear electrochemical dynamics and their sensitivity to load variations make a challenge to delivering stable power especially under dynamic operating conditions. This research aims to solve these issues by building a detailed mathematical model of PEMFCs based on electrochemical principles, voltage loss mechanisms, hydrogen consumption, and dynamic load behavior. One of the main objectives is to come up with a nonlinear control strategy and then verify the same so that it can be utilized to regulate output voltage, improve transient response, and enhance fuel utilization efficiency. Validation of the proposed Lyapunov-based nonlinear design of the controller was tested through MATLAB/Simulink. The performance under step, ramp, and fluctuating load conditions was then compared with that of classical PID and fuzzy-PID control methods. Simulation results demonstrate that the nonlinear controller achieves about 30% faster settling time, 40% less overshoot, and up to a 12% enhancement in hydrogen utilization efficiency than conventional methods. This instance testifies the robustness and better adaptability of the controller under real-world disturbances. The incremental research presents a scalable control framework for PEMFCs, bearing immense practical relevance in electric vehicles, microgrids, and futuristic smart energy systems.