METHOD AND CONTROLLER FOR CONTROLLING A POWER CONVERTER CONNECTED TO A GRID

A method for controlling a power converter connected to a grid, wherein the power converter is initially controlled in a grid-forming mode to output current at a nominal voltage, based on control data provided by a controller. The method includes determining that a first parameter exceeds a first threshold. Then: controlling the power converter in a first limiting mode, by limiting the power converter output current based on a present value and/or a reference value; and determining the output current of the power converter. Responsive to determining that the output current is reaching an equilibrium condition: determining a virtual impedance for the power converter; modifying the control system based on the virtual impedance; and controlling the power converter in a constrained grid-forming mode, including the modified control system determining the control data based on measured signals indicative of currents and/or voltages downstream from the power converter, and a reference signal.