Offshore Wind Turbine Rotor Torque Control for Motion Damping
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Solution Overview
Problem
Servicing of offshore wind turbines, particularly in deep waters, is challenging due to large waves, strong currents, and oscillating motions that make safe transfer of personnel and equipment difficult, limiting the service window and increasing safety risks.
Innovation Solution
An active motion control method for offshore wind turbines, using the generator to apply torque and thrust to control the wind turbine rotor, counteracting oscillations and positioning the turbine, facilitated by sensor feedback and yaw control, allowing safe servicing in adverse conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the offshore wind turbine operates in deep waters with large waves and strong currents, then the wind turbine can generate more electrical power, but the motion control and servicing safety deteriorates due to large oscillating motions
Solution Approach 1:
The system dynamically switches between different operating modes (power generation mode and motion control mode) based on operational requirements. In motion control mode, the generator is operated in motor mode to apply active damping torques that reduce oscillating motions, enabling safe servicing conditions while maintaining the ability to generate power when needed
2Loss of time
If the wind turbine rotor is operated to generate thrust for motion control, then the positioning accuracy improves, but the electrical power generation decreases due to active torque application
Solution Approach 1:
The system employs periodic active damping torques applied through the generator to counteract oscillating motions. These torques are applied in a periodic manner synchronized with the oscillation frequency, effectively reducing motions during servicing operations while allowing full power generation during normal operation
Solution Approach 2:
The operating mode is dynamically switched between power generation and motion control based on whether servicing operations are required. This dynamic adaptation allows the system to optimize for either power generation or motion reduction at different times, resolving the contradiction between these competing objectives
3Ease of operation
If active damping torques are applied to reduce oscillating motions, then the nacelle oscillation amplitude decreases, but the energy consumption increases due to generator operation in motor mode
Solution Approach 1:
Active damping torques are applied periodically rather than continuously, synchronized with the oscillation frequency of the nacelle. This periodic application reduces oscillations effectively while minimizing energy consumption compared to continuous torque application
Solution Approach 2:
The active damping is applied only partially - specifically during servicing operations when reduced oscillations are needed. The system does not continuously apply damping torques, but rather activates them selectively when required, thus avoiding excessive energy consumption while still achieving the desired ease of operation during critical periods
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances servicing safety and efficiency by reducing oscillations, extending the service window, and stabilizing the turbine for secure transfer, thereby reducing costs and improving operational uptime.
Implementation Method 1
by applying torque to the rotor, thus rotating the wind turbine rotor, thrust may be generated and a respective thrust force may be applied to the top of the tower of the OWT
Implementation Method 2
operating the wind turbine rotor to cause an application of a torque and/or force to an upper part of the tower of the OWT to control the motion of the OWT
Implementation Method 3
The generator is mechanically coupled to the wind turbine rotor and is configured to convert mechanical power received from the rotor into electrical power
Data Source
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AI summary
A method of controlling a motion of an offshore wind turbine (OWT) is provided. The OWT (100) comprises a tower (101), a wind turbine rotor (102), and a generator (120), wherein the generator (120) is mechanically coupled to the wind turbine rotor (102) and is configured to convert mechanical power to electrical power. The method comprises operating the OWT in an active motion control mode in which a motion of the OWT is controlled. Operation in the active motion control mode comprises operating the wind turbine rotor (102) to cause an application of a torque and/or force to an upper part of the tower (101) of the OWT to control the motion of the OWT. The wind turbine rotor (102) is operated by actively controlling a torque applied by the generator (120) to the wind turbine rotor (102).