Generalized Controller for Small Wind Turbines Working Grid-Connected and Stand-Alone

Distributed power generation systems may be required to work in both grid-connected and stand-alone modes for ensuring the supply of critical local loads, maybe organized in micro-grids. Every time the micro-grid is disconnected and reconnected from the grid, a change in the control scheme is required leading to undesired transients and even lost of stability. In this paper, the use of the droop control is extended to both operation modes without commutating the control schemes. An islanding detection method is employed together with a synchronization algorithm achieving a successful micro-grid reconnection procedure. Simulation results prove the effectiveness of the proposed solution.