Smart interconnection of a PV/wind DG micro grid with the utility distribution network

Future electric grids are becoming smarter by applying intelligent control techniques. Distributed Generation (DG) systems such as Photovoltaic (PV) and wind energy systems are essential parts of the future smart grids. In this paper, a smart interconnection control strategy is proposed for a grid connected PV/fixed speed wind driven micro grid. In case of industrial inductive loads, the generation of active power from the micro grid causes power factor decrease at the Point of Common Coupling (PCC) with the main grid. With the additional reactive power needs of the squirrel cage induction generator of the windsystem, the micro grid itself becomes a VAR burden. Proposed smart control strategy of the micro grid is based on the control of the PV coupling Voltage Source Inverter (VSI). The designed controller will ensure dual active/reactive power operation of the VSI. This will provide reactive power compensation, thus improving the power factor at the PCC as seen by the utility grid. Also, the control strategy will make use of the VSI during night time, thus cost effective for the micro grid. The proposed control algorithm is in the form of current controller implemented in synchronous rotating dq-frame. This allows decoupled control of active and reactive current components. Test system and controller operation and verification are implemented using MATLAB/Simulink Simpower System Toolbox.