Load sharing among converters in an autonomous microgrid in presence of wind and PV sources

Abstract

Power sources in a microgrid must be controlled in coordination with each other in order to meet optimization requirements and satisfy the operating criteria of the microgrid as a whole. Droop control is a distributed control method for sharing current components of the load between interface converters, where output voltage of each converter is controlled according to droop characteristics, to provide the proper sharing of any of load current components. As for wind and PV sources, active current reference is provided by MPPT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> system. If interface converters of these sources are controlled in a current-controlled mode to generate the desired active current, they will not be able to contribute to providing the other components of the load current with share factors that are determined by the objective function. This paper proposes a control scheme that allows the interface converters of wind and PV sources to generate active current according to the output of MPPT system and at the same time contribute to providing the other components with the share factors calculated by the objective function.