Segmented Stator Assembly with Flexible Busbar Connectors
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Solution Overview
Problem
Large wind turbine generators with segmented stators experience phase voltage imbalances and increased rotor eddy current losses due to manufacturing gaps, leading to reduced output power and thermal issues, which existing control algorithms cannot fully mitigate at the design phase.
Innovation Solution
A stator assembly with segment-to-segment connectors that electrically bridge gaps between adjacent stator segments, ensuring balanced phase voltages by connecting each coil to a busbar element assigned to the same phase, allowing for flexible and compact connections that reduce harmonic ripple and rotor eddy current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stator segments are separated by gaps due to manufacturing limitations, then assembly and manufacturing become easier, but phase voltage balance deteriorates and rotor eddy current losses increase
Solution Approach 1:
The patent introduces segment-to-segment connectors as intermediary elements that bridge the gaps between adjacent stator segments. These connectors provide electrical coupling that compensates for the discontinuity caused by manufacturing gaps, thereby maintaining phase voltage balance while allowing the segments to be manufactured and assembled separately.
Solution Approach 2:
The stator is divided into multiple separable stator segments that can be manufactured and assembled independently. This segmentation enables easier manufacturing and assembly while the segment-to-segment connectors ensure electrical continuity across the segment boundaries, resolving the contradiction between ease of manufacture and manufacturing precision.
2Ease of manufacture
If stator segments are separated by gaps, then manufacturing and assembly are simplified, but rotor eddy current losses increase leading to thermal issues
Solution Approach 1:
The segment-to-segment connectors act as intermediaries that maintain the magnetic flux continuity across stator segment boundaries. By providing a low-reluctance path for magnetic flux, these connectors reduce the disruption caused by gaps, thereby minimizing rotor eddy current losses while preserving the manufacturing advantages of segmented stators.
3Productivity
If control algorithms are used to minimize harmonic ripple, then operational performance improves, but the fundamental design problem of gap-induced imbalances remains unsolved
Solution Approach 1:
The segment-to-segment connectors are incorporated into the stator design during the manufacturing phase, preliminarily addressing the gap-induced imbalances before the generator operates. This preliminary structural solution eliminates the need for complex control algorithms to compensate for the imbalances, reducing operational complexity while maintaining high productivity.
4Temperature
If output power is decreased to maintain magnet temperature, then thermal safety is improved, but generator capacity is reduced
Solution Approach 1:
The segment-to-segment connectors reduce rotor eddy current losses by maintaining magnetic flux continuity, thereby reducing unwanted heating in the rotor magnets. This allows the generator to operate at higher output powers while maintaining magnet temperatures within safe limits, resolving the trade-off between thermal safety and power capacity.
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 solution achieves balanced phase voltages, reduces 2f and 4f harmonics, eliminates the need for active 2f ripple control, and enhances thermal capability, enabling higher output power and longer DC link capacitor lifespan.
Implementation Method 1
a segment-to-segment connector (250) connecting each busbar element of one first busbar arrangement (B1) of the first stator segment (210) to one busbar element, which is assigned to the same phase, of one busbar arrangement (B1 or B2) of the adjacent second stator segment (220)
Implementation Method 2
there are mounted a plurality of permanent magnets which, when moving along the stator segments, produce a time alternating magnetic flux through each electric coil. This time alternating magnetic flux induces an electric current in each electric coil.
Data Source
AI summary
Provided is a stator assembly including: i) a first stator segment, ii) a second stator segment, wherein the first stator segment and the second stator segment being arranged along a circumferential direction of the stator assembly, and wherein the first stator segment and the second stator segment are located adjacent to each other and are separated by a gap. The stator assembly further including: iii) at least one first coil set of a first multi-phase coil system, and iv) at least one second coil set of a second multi-phase coil system, wherein each coil set includes at least one coil for each phase of the respective multi-phase coil system. Each stator segment includes a first busbar arrangement having first busbar elements, and a second busbar arrangement having second busbar elements, each busbar element being assigned to one phase.