Method for testing a functionality of a system of a wind turbine, a controller and a drive system

A controller comprising:

• a processor configured to execute program code for testing a functionality of a system of a wind turbine, the system including an electro-mechanical actuator, an energy storage unit, and an energy dissipating element connectable to the energy storage unit for selectively transferring energy from the energy storage unit to the energy dissipating element;
• said processor being configured, when executing the program code, to:
• provide first information which is representative of an operating mode of the system, and, if the operating mode is a test mode:
• cause a discharging of energy from the energy storage unit and a supply of at least a portion of the discharged energy to the energy dissipating element;
• receive measurements being representative of a state of at least one of the energy storage unit and the energy dissipating element during the discharging and the supply;
• and,
• determine a functionality of at least one of the energy storage unit and the energy dissipating element based on the measurements.

A drive system for a wind turbine, the drive system comprising:

• an energy storage unit;
• an energy dissipating element connectable to the energy storage unit for transferring energy;
• a control device configured to control at least one of a discharging of said energy storage unit and a supply of at least a portion of discharged energy to said energy dissipating element;
• an electro-mechanical actuator;
• a controller for testing a functionality of a system of the wind turbine;
• said controller being configured to:
• provide first information which is representative of an operating mode of the drive system, and, if the operating mode is a test mode:
• cause a discharging of energy from said energy storage unit and a supply of at least a portion of the discharged energy to said energy dissipating element;
• receive measurements being representative of a state of at least one of said energy storage unit and said energy dissipating element during the discharging and the supply;
• and,
• determine a functionality of at least one of said energy storage unit and said energy dissipating element based on the measurements;
• and,
• wherein said controller is configured to control said control device in accordance with a test mode command.