Segmented Stator Coil Joining via Intermediary Bridge
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Solution Overview
Problem
The challenge in manufacturing segmented stators for direct drive electrical generators, particularly in wind turbines, lies in securely joining the end coils of stator segments while maintaining efficient electromagnetic performance and minimizing torque ripple, as existing solutions like dummy teeth or half teeth are inefficient and lead to performance loss.
Innovation Solution
The method involves manufacturing stator segments with concentrated windings, using pressure plates and mechanical hardware to secure the coils, followed by vacuum pressure impregnation, and joining the segments with phase separators or fiber glass insulators to ensure consistent slot extension and secure coil alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dummy teeth or half teeth are introduced at the circumferential ends of stator segments, then the segments can be joined together, but the electromagnetic performance is lost and torque ripple increases
Solution Approach 1:
The patent introduces an intermediary component (the end coil extending across the joint) that mediates between the need for segment joining and the requirement for electromagnetic performance. The end coil acts as a bridge that connects adjacent segments while maintaining the magnetic circuit integrity, thereby avoiding the need for dummy teeth that would disrupt the electromagnetic field distribution
Solution Approach 2:
The patent transitions from a two-dimensional slot-tooth structure to a three-dimensional configuration where the end coil extends circumferentially across the segment joint. This dimensional change allows the coil to span the gap between segments, providing both mechanical connection and electromagnetic continuity without requiring additional teeth structures
2Power
If concentrated winding topology is used in segmented stators, then smaller coil overhang and increased torque are obtained, but the end coil must extend across segment joints creating manufacturing complexity
Solution Approach 1:
The patent merges the mechanical joining function with the electromagnetic function by having the end coil serve both purposes. The end coil is not just an electrical component but also acts as the mechanical element that connects adjacent stator segments, thereby combining two functions into a single integrated component
Solution Approach 2:
The patent performs preliminary action by pre-positioning the end coil to extend across the segment joint before the actual segment assembly. This allows the coil to be securely attached to the segment body in advance, and then the segment can be joined to adjacent segments with the coil already in place, simplifying the overall assembly process
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 approach allows for efficient assembly of stator segments with consistent slot extensions, maintaining electromagnetic performance and reducing torque ripple, thereby enabling the effective integration of concentrated winding topology with segmented design.
Implementation Method 1
a vacuum pressure impregnation is applied to the stator segment and to the coil concentrated winding previously provided in the slots of the segment body
Data Source
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AI summary
A method of manufacturing a segment (10) for a stator of an electrical generator includes: - a first step (105) of manufacturing a segment body (11) circumferentially extending between at least a first end slot (21) and a second end slot (22), - a second step (107) of providing the coil concentrated winding (12) in the slots (21, 22, 23) of the segment body (11), - a third step (110) of providing a first pressure plate (51) a second pressure plate (52) for respectively holding the coil in the first end slot (21) and the second end slot (22), - a fourth step (115) of applying vacuum pressure impregnation to the coil concentrated winding (12) in the slots (21, 22, 23) of the segment body (11), - a fifth step (120) of removing the first pressure plate (51) and the second pressure plate (52) for obtaining the segment (10).