Capacitor PITCH System – Compact PITCH for Wind Turbines
The new capacitor PITCH system with asynchronous motor is a PITCH system for wind turbines in the 1.5 MW class. The electrical PITCH system stands out due to its compact design, an energy store with extended service life and freedom from maintenance. Due to the servo properties of the PITCH motor, position control with quartz accuracy is even possible in the case of small positional changes at a low speed. The system consists of three control cabinets, each of which is of a compact design. Freedom from maintenance is guaranteed by the use of asynchronous motors. The condensers are a reliable and long-lasting energy store and can be operated at temperatures of -40 °C to +60 °C in the control cabinets. The capacitors which are able to handle a high current guarantee high levels of availability of the wind turbines due to their robust and maintenance-free design.
For each axis of the PITCH system there is a completely independent working system which has a charging device for the energy store, lightning protection and the PITCHmaster PLC. Furthermore, each box generates its own control voltage for supplying the 24 V components in the case of a power failure. Each axis can react with an emergency propulsion function in the case of a field bus failure even without control of the head and move the system to the safe vane position. If the position encoder fails, this can also be performed without the encoder. The variable number of axes and the reduction in the slip ring contacts as well as the clearly laid out box-to-box wiring also contribute towards helping the capacitor PITCH system to guarantee the availability of wind turbines.
