Design and Experimental Validation of Hydraulic Yaw System for Multi MW Wind Turbine

To comply with the increasing demands for life time and reliability of wind turbines as these grow in size, new measures needs to be taken in the design of wind turbines and components hereof. One critical point is the initial testing of the components and systems before they are implemented in an actual turbine. Full scale hardware testing is both extremely expensive and time consuming, and so the wind turbine industry moves more towards simulations when testing.
In order to meet these demands it is necessary with valid models of systems in order to introduce new technologies to the wind turbine market. A hydraulic yaw system is such a new technology, and so a mathematical model of the full scale system and test rig system is derived and compared to measurements from the system. This is done in order to have a validated model, which wind turbine manufacturers may use for test in their simulation environment. The model and the test rig are tested up against different design load cases and the results are compared. The experiments show that the model is valid for comparing the overall dynamics of the hydraulic yaw system. Based on the results it is concluded that the model derived is suitable for testing of the dynamic behavior in wind turbine manufacturer’s full scale aero elastic code.