A method for controlling an inverter-based resource having a power converter connected to an electrical grid includes receiving, via a regulator of a controller of the inverter-based resource, a plurality of power signals. The method also includes determining, via the regulator, a power error signal as a function of the plurality of power signals. Further, the method includes receiving, via the regulator, a dynamic multiplier factor from a supervisory controller. Moreover, the method includes applying, via the regulator, the dynamic multiplier factor to one or more gains of the regulator to determine one or more modified gains. In addition, the method includes applying the one or more modified gains to the power error signal to obtain an intermediate power signal. Thus, the method includes generating, via the regulator, one or more control commands for the power converter as a function of the intermediate power signal.