In modern wind power plants, the power output from the wind is adapted to the changing wind conditions. In the strong wind range, power output is limited to protect the turbine. The rotor blade adjustment serves this purpose. By adjusting the angle, this changes the forces acting on the rotor blade. In the normal wind range, power consumption is optimised by means of variable speed generator systems.
ET 210 demonstrates a wind power plant with rotor blade adjustment and variable speed generator.
The wind power plant stands on a tower in a wind tunnel. The air flow is generated by an adjustable speed fan. A flow straightener ensures consistent and low-turbulence flow. A three-blade rotor drives the generator directly. The rotor blades can be easily replaced. The wind tunnel is closed during the experiments to ensure that the experiments are conducted safely.
In order to approach different operating points, the target speed of the rotor can be set via the software. The rotor blade adjustment is operated by means of a servomotor to change the rotor blade adjustment angle. The angle between the rotor axis and the wind direction (yaw angle) can be adjusted by means of a handwheel.
The rotor speed is precisely measured by Hall sensors built into the generator. The wind velocity is measured by a horizontally adjustable wind velocity sensor, so that the average wind velocity over the rotor surface can be recorded. The yaw angle is measured by an angle sensor. The measured values are transmitted directly to a PC via USB where they can be displayed and analysed using the software included. The software calculates the converted electrical power, the generator torque and system-specific parameters.