An improved control scheme based in droop characteristic for microgrid converters

In the present work, an improved version of the conventional-droop control for microgrid converter is presented. The modifications added to the control are based on a feed-forward current control that allows the converter to work in several modes, both when it is grid connected or in island. The use of this control represents the main contribution of this paper, permitting the inverter to work as a grid supporting source or ancillary services provider when it works grid connected. In this mode the converter varies the injected active and reactive power with the variation of voltage module and frequency using the same main control loop as when it is working in island mode.