Dynamic Self-Reconfiguration of a Buck-Boost PV Inverter for Maximum Energy Harvesting

High efficiency is a primary goal for photovoltaic (PV) inverters. Optimization procedures followed by PV inverter designers result in static circuit designs, with respective efficiency curves that exhibit their maxima in a narrow range of PV array voltage and power. Nevertheless, the individual PV array characteristics, the solar irradiance and ambient temperature conditions with their daily and seasonal variations, as well as possible partial shading of the PV array, normally shift the operating point of PV inverters away from their maximum-efficiency range. This paper proposes a dynamic self-reconfiguration method for transformerless Buck-Boost PV inverters. The proposed method involves extending the PV inverter’s power circuit with appropriately selected components and reconfiguring its structure and switching frequency in real-time, so that its efficiency is maximized under any operating conditions. The experimental results obtained using a reconfigurable Buck-Boost PV inverter prototype demonstrate that by applying the proposed technique, the PV inverter’s energy efficiency can be increased by 1.5%.