Movable Stator Subunits for Wind Turbine Generator Air Gap Control
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Solution Overview
Problem
Existing wind turbine generators face challenges in accurately controlling the small air gap between the rotor and stator, which is crucial for maintaining high precision and efficiency, especially for large diameters, and also require easy maintenance access.
Innovation Solution
The generator design features movable stator subunits with flux-generating modules arranged on opposing sides of the rotor, allowing for transverse movement to maintain a constant air gap and facilitate service by using a hinge connection for access, with passive flexibility provided by the stator support structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rotor and stator are designed very rigid and heavy to maintain high precision air gap, then the air gap precision is improved, but the weight and complexity of the generator increases
Solution Approach 1:
The stator is divided into multiple independent subunits that can move relative to each other. Each subunit contains flux-generating modules that face the rotor. This segmentation allows individual adjustment of each subunit to maintain precise air gap without requiring the entire stator to be rigid and heavy.
Solution Approach 2:
The stator subunits are made movable relative to each other along a direction transverse to the rotor's moving direction. This dynamic capability allows the subunits to adjust their positions to compensate for rotor irregularities and maintain constant air gap, replacing the need for rigid structures.
2Reliability
If the stator is made rigid to maintain constant air gap, then the air gap stability is improved, but the ease of maintenance deteriorates
Solution Approach 1:
The stator is segmented into movable subunits that can be independently positioned. During maintenance, these subunits can be moved relative to each other to create access to the rotor-stator region, while still maintaining air gap stability during normal operation.
Solution Approach 2:
The movable subunits provide dynamic adjustment capability. During operation, they maintain stable air gap; during maintenance, they can be repositioned to allow access to internal components, solving the contradiction between stability and maintainability.
3Productivity
If the air gap is made very small to improve generator efficiency, then the power density is improved, but the difficulty of maintaining constant air gap increases
Solution Approach 1:
Dividing the stator into multiple subunits with independent movement capability simplifies the control of small air gaps. Each subunit can be individually adjusted to compensate for variations, making it easier to maintain constant air gap compared to a monolithic structure.
Solution Approach 2:
The dynamic movement of subunits along the transverse direction provides automatic compensation for air gap variations. This reduces the complexity of air gap control by using passive mechanical adjustment rather than complex active control systems.
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
This design enables precise control of the air gap, reduces fluctuations in power production, allows for independent operation of subgenerators, and simplifies maintenance by providing access to the rotor-stator region.
Implementation Method 1
The rotor and the flux-generating modules of the stator include permanent magnets, electromagnetic windings, combinations thereof, or other active materials configured to provide a magnetic flux across the air gap sufficient to generate electricity.
Data Source
AI summary
A generator (5) for a wind turbine (1) is disclosed. The generator (5) comprises a rotor (3) configured to rotate about a rotational axis, and at least one stator (4) arranged next to the rotor (3). Each stator (4) comprises at least two subunits (8), the subunits (8) being arranged side-by-side along a moving direction of the rotor (3). Each subunit (8) comprises at least one flux-generating module (9) facing the rotor (3) but spaced therefrom, thereby defining an air gap between the rotor (3) and each flux-generating module (9). The subunits (8) are movable relative to each other along a direction which is substantially transverse to the moving direction of the rotor (3). This allows a subunit (8) to move in a manner which adjusts the air gap without affecting the position and the air gap of a neighboring subunit (8). Thereby variations in the rotor (3) can be compensated and a uniform and constant air gap can be maintained. The invention further provides a wind turbine (1) comprising such a generator (5) and a method for performing service on a generator (5).