Patent ID: 8188610

Claim:
A wind turbine comprising: a main generator configured to produce electrical output power to be fed into a utility grid up to a rated generator output power; a main power converter connected to the main generator and configured to convert the electrical output power of the main generator to an electrical power to be fed into the utility grid up to a first rated converter output power; an auxiliary power converter electrically connected to the main generator and configured to convert the electrical output power of the main generator to an electrical power up to a second rated converter output power which is lower than the first rated converter output power; and an internal supply grid, wherein the auxiliary power converter comprises an auxiliary frequency converter which comprises a controller configured to operate the auxiliary frequency converter in a grid-tie mode and in a stand-alone mode; wherein, in the grid-tie mode, the auxiliary frequency converter matches at least one phase with a sine wave supplied by the utility grid or the main power converter and maximizes power output; and wherein, in the stand-alone mode, the auxiliary frequency converter provides a power supply of the internal supply grid.