Coordinated control of multi-functional grid-tied inverters using conductance and susceptance limitation

Owing to the numerous non-linear and reactive local loads, the applied grid-tied inverters etc., the quality of power supply of micro-grids becomes a challenging issue need to be highly addressed. As the power quality can significantly affect the secure, stable, effective and economic operation of the micro-grids, the compensation of the harmonic and reactive current in the micro-grids by the use of power quality conditioners and/or advanced control strategies has been highlighted. In this study, the multi-functional grid-tied inverters (MFGTIs) are attempted to interface renewable energy resources and enhance the power quality within the micro-grid. The MFGTIs encompassed with the coordinated control strategy based on the Fryze-Buchholz-Dpenbrock (FBD) theory. Through limiting the harmonic and reactive conductance and susceptance detected by FBD theory, the harmonic and reactive current within the micro-grid can be shared among the MFGTIs in a coordinated and automatic fashion in accordance with their capacities without communication. A set of the experiments based on the micro-grid test-bed are carried out and the results confirm the effectiveness and feasibility of the suggested control strategies.