Design and implementation of a solar power optimizer for module level power electronics application

Abstract

Partial shading on series-connected photovoltaic (PV) panels in conventional PV systems results in lower harvested power. To resolve this, it is vital to utilize module level power electronics (MLPE) such as Solar Power Optimizers (SPOs). This paper introduced a non-isolated common ground non-inverting output voltage buck-boost converter as an SPO. Proposed converter benefits from continuous input and output currents which has a significant role in designing SPOs. Having a quadratic gain, beside acceptable step-down range are other features of the converter. Operating principle, design, steady-state, small-signal analysis, and dynamic performance of proposed converter are included. Proposed converter is compared with other buck-boost converters in terms of voltage gain, voltage stresses, continuous input and output current, and output polarity. To validate the performance of introduced converter, experimental results for a prototype with input voltage 24 V, output voltage 72 V for step-up and 15 V for step-down modes are given and results are examined. The maximum efficiency of the prototype is 93% and 89% for step-up and step-down modes, respectively. To evaluate the effect of proposed SPO for extracting maximum available power from PVs, simulation results of a grid connected PV system with two series connected SPOs is discussed.