Wind turbine having a main power converter and an auxiliary power converter and a method for the control thereof

A power generation plant for converting a variable renewable energy source, comprising

• an internal supply grid for feeding electrical consumers of the power plant;
• a main generator adapted to produce electrical 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 adapted to convert the electrical output power of the main generator to an electrical power adapted to be fed into the utility grid;
• and
• an auxiliary power converter connected to the main generator and adapted to convert the electrical output power of the main generator up to a rated converter output power which is at least one order of magnitude lower than the rated generator output power, the auxiliary power converter being further adapted to provide a power supply for the internal supply grid.

A wind turbine comprising:

• a main generator comprising a generator rotor, the main generator being adapted to produce electrical power to be fed into a utility grid up to a rated generator output power;
• a first frequency converter connected to the main generator and adapted to convert the electrical output power of the main generator to an ac electrical power at the frequency of the utility grid, the first frequency converter comprising a first controller adapted to control the power input from the main generator in accordance to power set points;
• a main controller being adapted to control the speed of the generator rotor by measuring the rotor speed and issuing power set points to the first controller;
• and
• a second frequency converter connected to the main generator and adapted to convert the electrical output power of the main generator to an ac electrical power at the frequency of the utility grid, the second frequency converter comprising a second controller adapted to control the power input from the main generator independent of the main controller.

A control architecture for controlling the power balance of a wind turbine comprising a main generator comprising a generator rotor, comprising

• a first master controller adapted to change the torque balance of the generator rotor;
• and
• a second master controller adapted to change the torque balance of the generator rotor;
• the first master controller and the second master controller being further adapted to operate in a master to master mode.

A method for operating a wind turbine comprising a main generator adapted to produce electrical power to be fed into a utility grid up to a rated generator output power;

• comprising:
• providing a main power converter connected to the main generator and adapted to convert the electrical output power of the main generator to an electrical power adapted to be fed into the utility grid up to a first rated converter output power;
• providing an auxiliary power converter connected to the main generator and adapted to convert the electrical output power of the main generator to an electrical power up to a second rated converter output power, the second rated converter output power being lower than the first rated converter output power;
• and
• activating the auxiliary power converter.