Recent advancements in renewable energy, particularly the widespread deployment of photovoltaic systems within power sectors, have introduced notable challenges in terms of their operational intricacies, protection, and control mechanisms. This paper aims to enhance the stability and performance of a non-isolated step-down converter by implementing a Fractional–Order Proportional–Integral–Derivative (FOPID or \({\text{PI}}^{\uplambda }{\text{D}}^{\updelta }\) ) controller. A novel Artificial Intelligence (AI) tuning method is specifically designed to optimize the FOPID controller parameters, utilizing the Artificial Hummingbird Algorithm (AHA) optimizer. A comparative analysis with the conventional PID controller is conducted. Simulation results demonstrate a significant enhancement in the transient performance of the DC–DC buck converter dynamics when employing the AHA-optimized FOPID controller.