Power Compensation and Control System for Partially Shaded PV Array

Abstract

The power-voltage and current-voltage characteristics of a PV array change with the variation of insolation and temperature. Especially, the output power of a PV-panel block consisting of series-PV modules inevitably goes down due to partial shading caused by peripheral obstacles. This results in the significant reduction of the total output power from the PV power generation system where a couple of PV blocks are parallel to the DC terminal of interactive inverter because of mismatch of the optimum operating voltages between the PV blocks.
In this paper, we propose a power convertion system to compensate the output power of a partially shaded PV array. The proposed system can control the output power of the PV array on a PV block basis, which contributes to a more efficient and simpler implementation of the PV power compensation system than that by individual controls of PV modules using DC-DC converters. In addition to that, inverter DC voltage is appropriately controlled so that the maximum output power from the overall PV array can be obtained. And then, the feasibility of the system is investigated and verified from the simulation and experimental results.