Supervisory and control systems for wind turbines

Abstract

The Western mill was the first wind turbine which operated completely automatic, “without a human supervisor”. But the tasks of the control system and the supervisory system were strongly interwoven. The main vane which adjusts the rotor to the wind direction is in fact a simple “all-in-one” control system: it is sensor to register the deviation between the wind direction and the rotor axis, and at the same time it is the actuator producing the forces for the correction of the deviation from the demand value, Fig. 12-1. Together with the transverse vane it controls the turbine in the entire operating range from standstill to storm protection: For very strong winds the spring extends and the rotor is turned to increase the angle between rotor axis and wind direction. Rotational speed, power extraction and thrust are reduced, see also Fig. 12-7 (yaw angle β), and annex I of this chapter. In this annex additional examples of simple mechanical control systems for small wind turbines are presented.