Direct-Drive Wind Turbine Rotor Sensor Layout for Accurate Hub Speed
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Solution Overview
Problem
Existing direct drive wind turbines face challenges with maintenance accessibility and measurement accuracy of rotation sensors due to their large size and suspension between the hub and stator, leading to obstructed access and low resolution.
Innovation Solution
A rotation sensor with a static element mounted on the stator and a moving element integrated with the rotor, positioned at a significant radial distance from the hub's rotation axis, allowing for high accuracy and easy maintenance access by being located outside the generator's cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotation sensor is suspended between the hub and the stator of the generator, then the rotational velocity of the hub can be monitored, but access to components such as the hub is partially blocked, making maintenance more difficult and time-consuming
Solution Approach 1:
The rotation sensor is extracted from the cavity between the hub and stator and relocated to the outer surface of the stator. This extraction removes the sensor from the maintenance path, allowing technicians to access the hub cavity without dismantling sensor components, while the sensor continues to monitor hub rotation through its proximity to the rotating structure.
Solution Approach 2:
The rotation sensor acts as an intermediary measurement device positioned on the stator outer surface, measuring hub rotation indirectly through its magnetic or optical field interaction with the rotating hub or rotor, rather than requiring direct contact or placement within the maintenance path.
2Measurement precision
If the rotation sensor is large and suspended in the cavity of the stator, then it can monitor the hub rotation, but access to components such as the hub is partially blocked
Solution Approach 1:
The rotation sensor is extracted from the stator cavity and mounted on the outer surface of the stator. This removes the sensor from the cavity space, freeing up the entire cavity for maintenance access and component assembly, while the sensor maintains its monitoring function through external positioning.
3Measurement precision
If the rotation sensor is positioned close to the hub rotation axis, then it can monitor rotation, but the resolution of measurement is low
Solution Approach 1:
The measurement approach transitions from radial positioning (close to the rotation axis) to tangential positioning (on the outer surface of the stator). By placing the sensor on the stator's outer surface, the measurement lever arm is maximized, achieving high resolution through the large circumferential distance from the rotation axis without compromising monitoring capability.
4Ease of manufacture
If the moving element of the rotation sensor is not formed integrally with the rotor, then assembly may be easier, but movement between the hub and stator results in measurement inaccuracies
Solution Approach 1:
The moving element of the rotation sensor is merged with the rotor structure, forming an integral assembly. This ensures that the sensor moves precisely with the rotor without relative movement or misalignment, eliminating measurement inaccuracies that would result from independent movement of separate components.
Data Source
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AI summary
The invention discloses a direct drive wind turbine (1) comprising a plurality of blades connected to a hub (6), a generator comprising a stator (12) and a rotor (10), the stator (12) being fixed on a nacelle (4) of the wind turbine (1) and a rotation sensor having a static element (30) and a moving element (34). The hub (6) is directly connected to the rotor (10) of the generator. The static element (30) of the rotation sensor is mounted on a stationary element of the wind turbine, in particular the stator (12), at a distance from the rotation axis (R) of the hub (6), and the moving element (34) of the rotation sensor is mounted on the rotor (10) of the generator at a distance from the rotation axis (R) of the hub (6).