Performance of a Single-Stage Buck-Boost Inverter Fed from a Photovoltaic Source Under Different Meteorological Conditions

This paper describes the implementation and performance evaluation of a single-stage buck-boost inverter to extract the maximum power (MP) from a photovoltaic (PV) source under different meteorological conditions. The considered system reduces Power Electronic (PE) devices that are required for the maximum power point tracking and the DC/AC inverting stages to only four switches. A Maximum Power Point Tracker (MPPT) is designed, based on the particle swarm optimization (PSO), to enable the system operation at the Global Maximum Power Point (GMPP), which avoids the local MPPs that exist during partial shading. The PSO algorithm generates a signal proportional to the MPP and inputted to the single-stage buck-boost inverter via a control circuit that generates the four shifted pulses required to operate the four PE switches. A DSP-based PV laboratory model is built to assess the single-stage inverter experimentally. The PSO-based MPPT algorithm is implemented on-line to extract the maximum power and produces a sinusoidal AC output during non-uniform solar irradiation and the results are presented, illustrating successful operation of the single-stage buck-boost to track the MPP under partial shading and sever fluctuations in solar irradiation.