ENERCON E-82 E4 - Control System; Yaw System; Pitch Control

6 Control system
The E-82 E4 control system is based on a microprocessor system developed by ENERCON and
uses sensors to query all WEC components and collect data such as wind direction and wind
speed. Using this information, it adjusts the operating mode of the E-82 E4 accordingly. The WEC
display of the control cabinet in the tower base shows the current status of the wind energy con‐
verter and any fault that may have occurred.
6.1 Yaw system
The yaw bearing with an externally geared rim is mounted on top of the tower. The yaw bearing
allows the nacelle to rotate, thus providing for yaw control.
If the difference between the wind direction and the rotor axis direction exceeds the maximum per‐
missible value, the yaw drives are activated and adjust the nacelle position according to the wind
direction. The yaw motor control system ensures smooth starting and stopping of the yawing mo‐
tion. The WEC control system monitors the yaw system. If it detects any irregularities it deactivates
yaw control and stops the wind energy converter.
6.2 Pitch control
Functional principle
The pitch control system modifies the angle of attack, i.e., the angle at which the air flow meets the
blade profile. Changes to the blade angle change the lift at the rotor blade and thus the force with
which the rotor blade turns the rotor.
During normal operation (automatic mode) the blade angle is adjusted in a way that ensures opti‐
mal exploitation of the energy contained in the wind while avoiding overload of the wind energy
converter. Wherever possible, boundary conditions such as noise optimisation are also fulfilled in
the process. In addition, blade angle adjustment is used to decelerate the rotor aerodynamically.
If the wind energy converter achieves nominal power output and the wind speed continues to in‐
crease, the pitch system turns the rotor blades just far enough out of the wind to keep the rotor
speed and the amount of energy extracted from the wind, i.e., the energy to be converted by the
generator, within or just slightly above the rated limits.
Assembly
Each rotor blade is fitted with a pitch unit. The pitch unit consists of a pitch control box, a blade
relay box, a pitch motor and a capacitor unit. The pitch control box and the blade relay box control
the pitch motor. The capacitor box stores the energy required for emergency pitching; during WEC
operation, it is kept charged and tested continually.
Control system
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