Passivity-Based Control Approach for Photovoltaic DC-DC Conversion and Output Voltage Regulation

This article introduces a novel control approach for tackling the maximum power point tracking (MPPT) and output voltage regulation (VR) in photovoltaic (PV) cell systems. Leveraging the port-Hamiltonian (pH) formalism, an energy-based framework known for its physically multidomain modeling and control methodologies, our proposed control law offers promising solutions. Our control design is rooted in an interconnection damping assignment passivity-based strategy, incorporating temperature dependencies of the internal PV cell parameters. To validate the efficacy of our approach, we modeled, implemented, and calibrated a prototype system comprising a PV cell, a dc-dc buck converter, and a dc-dc boost converter that feeds a battery load. The entire setup is designed within the pH framework, ensuring a cohesive integration of energy-based control. To highlight our energy-based strategy's reliability and performance, we evaluated it against a commercial solar charger under real solar irradiance conditions. Our experimental findings unequivocally demonstrate that the control mechanism employed by the commercial solar charger demands a significantly higher amount of energy and exhibits a premature collapse at lower power levels when compared to our proposed system and control strategy.