Constrained MPPT based control of a photovoltaic DC to DC conversion system using a non inverting buck boost converter

This paper presents a Constrained Maximum Power Point Tracking Algorithm (CMPPTA) integrated with a Non Inverting Buck Boost Converter (NIBBC) for photovoltaic (PV) energy conversion. Unlike conventional Perturb and Observe (P&O) methods, CMPPTA uses a constrained duty-cycle update law with adaptive bounded perturbation, saturation enforcement, and a local hold region near the maximum power point (MPP). The duty cycle is limited to Dₘᵢₙ=0.1 and Dₘₐₓ=0.9 , with practical operation mainly within 50–60%. The controller is implemented on an ARM Cortex-M4 STM32F407VGT6 microcontroller and validated through MATLAB/Simulink simulation and laboratory hardware testing. The simulation uses a 200 W equivalent PV array, while the prototype uses a single 40 W PV module. Under 300–1000 W/m ² simulation, CMPPTA achieves 96.63% peak DC conversion efficiency. Under 270–1000 W/m ² laboratory testing, hardware efficiency reaches 84.48%. CMPPTA reduces cumulative tracking error by 18.7% relative to IC and 24.1% relative to P&O. The present validation is limited to MPPT execution and DC–DC converter operation; outdoor testing, partial shading, temperature variation, storage integration, and inverter-level validation remain future work. Accordingly, the reported results validate the proposed controller at the MPPT and DC–DC converter levels only, and should not be interpreted as full-system validation of storage, inverter, grid-interface, or application-side load operation.