iBAC

iBAC - Intelligent Bearing Amplitude Control

• The iBAC research project is focused on a central conflict associated with the operation of wind turbines: How can the highly stressed and sensitive blade bearings be protected effectively from damage without subjecting the adjacent components to additional loading and generating a lower energy yield?
• The aim of this project is thus to develop an intelligent condition monitoring system (CMS) which, in combination with a reliability controller, achieves the ideal balance between blade bearing protection and energy yield and the service life of the wind turbine.
• Within the scope of a sub-project, Fraunhofer IWES is responsible for tests on scaled blade bearings, the calculation of optimal protective cycles based on these tests and turbine simulation, and the development of a reliability controller.

The blade bearings of wind turbines are among the parts subject to the greatest loading. As such, damage can be incurred which is both time- and cost-intensive to repair. This causes repair costs and yield losses for operators as the turbine is unable to operate.

Blade bearings are operated under demanding and unfavorable conditions for rolling bearings: blade control which is tailored for optimal energy yields, namely oscillating movements and extended downtimes, result in adverse lubrication conditions between the rolling elements and the raceways, which, in turn, can lead to damages and failures of the blade bearings.

These unfavorable lubrication conditions can be prevented or reduced by means of lubrication runs or protective cycles, which, however, could have a negative impact on the energy yield and the loading of other components such as rotor blades and the wind turbine tower. The goal of the iBAC project is to identify the ideal solution to this problem and to implement this in the turbine control.

The project partners are developing an intelligent CMS which can display the current status of the blade bearings as well as critical operating conditions. Furthermore, an intelligent control strategy is to be developed which, taking the blade bearing CMS into account, enables a lubrication run or a protective cycle to be performed, yet still operates the wind turbine optimally.

Fraunhofer IWES is responsible for the following aspects within the scope of a sub-project:

• Tests on 100 scaled blade bearings with  diameters of approx. 1 m
• A complete turbine simulation with realistic mapping of the pitch system
• The model-based calculation of optimal protective cycles
• The development of a reliability controller which integrates the protective cycles into the operation of the wind turbines