Wind Turbine Generator Airgap Control for Torque and Collision Prevention
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Solution Overview
Problem
Electric generators in wind turbines face airgap deformation due to magnetic pull, eccentricity, manufacturing tolerances, and thermal deformation, leading to non-uniform airgaps and reduced torque production, necessitating a larger designed airgap to prevent collisions.
Innovation Solution
A controller system that uses sensors to measure and control the current in winding systems to generate magnetic radial forces, adjusting the airgap between the stator and rotor to maintain a threshold value, thereby preventing collisions and optimizing torque production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the airgap is designed to be larger to account for deformations and tolerances, then collision between stator and rotor is prevented, but torque production is reduced
Solution Approach 1:
The patent implements dynamic airgap control by actively adjusting the airgap thickness during operation based on real-time measurements. The controller modifies the airgap to maintain optimal values under different operating conditions, transforming the static airgap design into a dynamic system that adapts to prevent collisions while maximizing torque production.
Solution Approach 2:
The system uses sensors to continuously measure the airgap thickness and feeds this information back to the controller. The controller then adjusts the airgap based on this feedback to maintain it above a threshold value, preventing collisions while optimizing performance. This closed-loop control resolves the contradiction by reacting to actual conditions rather than relying on conservative static design.
2Power
If the airgap is reduced to increase torque production, then higher power output is achieved, but the risk of collision between stator and rotor increases
Solution Approach 1:
The airgap is transformed from a fixed design parameter to a dynamically adjustable parameter. The system actively controls the airgap thickness during operation, allowing it to be reduced when conditions permit (maximizing torque) and increased when needed (preventing collisions), thus resolving the static trade-off.
Solution Approach 2:
The controller takes preliminary action by adjusting the airgap before a collision can occur. When the airgap approaches the threshold value, the controller proactively increases it to prevent collision, rather than waiting for a security system to stop the generator after a collision risk is detected.
3Reliability
If security systems are implemented to stop the generator when airgap reaches minimum threshold, then collision is prevented, but energy production is reduced
Solution Approach 1:
The system takes preliminary action by continuously controlling the airgap to maintain it above the minimum threshold, preventing the need for emergency shutdowns. The controller anticipates potential collision risks and adjusts the airgap in advance, allowing continuous operation and maximizing energy production.
Solution Approach 2:
The closed-loop control system continuously monitors airgap thickness and adjusts it in real-time based on feedback from sensors. This prevents collisions before they occur while allowing the generator to operate continuously at optimal performance, eliminating the need for productivity-reducing security shutdowns.
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
The solution allows for a more uniform airgap, preventing undesired collisions and enhancing torque density and Annual Energy Production (AEP) by dynamically controlling the airgap, ensuring efficient operation without the need for security systems that halt the generator.
Implementation Method 1
controlling the current flowing in at least one of the winding systems so that a respective magnetic radial force is generated, the magnetic radial force acting on the stator and/or rotor for increasing the airgap
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention describes an electric generator (11) for a wind turbine (1) comprising a stator (20) or rotor (30), the stator (20) or rotor (30) having plurality of winding systems (41, 42, 43, 44), each winding system (41, 42, 43, 44) covering a respective angular portion of the stator (20) or rotor (30) about an axis of rotation (Y) of the electric generator (11), and a controller (50) for controlling the current flowing in the winding systems (41, 42, 43, 44). The controller (50) is configured for receiving or determining a thickness of an airgap (10) between the stator (20) and the rotor (30) and controlling the current flowing in at least one of the winding systems (41, 42, 43, 44) so that a respective magnetic radial force is generated, the magnetic radial force acting on the stator (20) and/or rotor (30) for increasing the airgap (10) where the airgap (10) is below a threshold airgap value.