A wind turbine system comprising: a wind turbine generator operable to supply wind turbine power to a utility system; a converter coupled to the wind turbine generator and the utility system; and a controller comprising an internal reference frame of the wind turbine generator; said controller coupled to the converter and configured for modulating flow of power through the converter in response to frequency disturbances or power swings of the utility system relative to the internal reference frame; characterized in that: said internal reference frame is implemented as an integrator emulating a virtual inertial; said internal reference frame configured to provide a variable reference frequency output signal; said controller is adapted to use said reference frequency output signal to provide a supplemental input signal as an input signal to wind turbine controls for controlling turbine features such as blade pitch or turbine speed so as to increase or decrease power output of the wind turbine system; and said controller is further adapted to provide said supplemental input signal to summing element for summing with a torque or power command signal from wind turbine controls to provide an input signal to the converter to modulate flow of power through the converter. a wind turbine generator operable to supply wind turbine power to a utility system; a converter coupled to the wind turbine generator and the utility system; and a controller comprising an internal reference frame of the wind turbine generator; said controller coupled to the converter and configured for modulating flow of power through the converter in response to frequency disturbances or power swings of the utility system relative to the internal reference frame; characterized in that: said internal reference frame is implemented as an integrator emulating a virtual inertial; said internal reference frame configured to provide a variable reference frequency output signal; said controller is adapted to use said reference frequency output signal to provide a supplemental input signal as an input signal to wind turbine controls for controlling turbine features such as blade pitch or turbine speed so as to increase or decrease power output of the wind turbine system; and said controller is further adapted to provide said supplemental input signal to summing element for summing with a torque or power command signal from wind turbine controls to provide an input signal to the converter to modulate flow of power through the converter. said internal reference frame is implemented as an integrator emulating a virtual inertial; said internal reference frame configured to provide a variable reference frequency output signal; said controller is adapted to use said reference frequency output signal to provide a supplemental input signal as an input signal to wind turbine controls for controlling turbine features such as blade pitch or turbine speed so as to increase or decrease power output of the wind turbine system; and said controller is further adapted to provide said supplemental input signal to summing element for summing with a torque or power command signal from wind turbine controls to provide an input signal to the converter to modulate flow of power through the converter.