Controller for controlling a power converter

It is described a controller for controlling a power converter for a wind turbine, the power converter for converting an electrical input power of the wind turbine into an electrical output power, wherein the electrical output power is provided to a grid. The power converter comprises a grid-side converter part and a turbine-side converter part. The controller comprises an input terminal for receiving a voltage reference signal being associated with a predefined grid voltage and a frequency reference signal being associated with a predefined grid frequency, and a network bridge controller being adapted to control the power conversion of the grid-side converter part. The network bridge controller comprises a modulator for modulating gate drive command signals in the grid-side converter part based on a reference voltage and a reference angle being derived from the voltage reference signal and the frequency reference signal. The modulator is adapted to modulate the gate drive command signals in order to maintain the predefined grid voltage and the predefined grid frequency in the power converter in the case of a failure within the grid.