Plug 'n' play interface for renewable generators participating in grid voltage and frequency control

At high penetration grades of renewable power sources in public and autonomous grids, the control of frequency and voltage requires special attention. In this paper a method of operation of power electronic interfaces is described for connection of renewable generators to the grid, where the interface fulfils several tasks: (1) it participates in the power/frequency control; (2) it participates in the voltage control; and (3) it operates without additional communication (plug and play).