Segmented Stator End-Tooth Geometry for Harmonic Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Segmentation of stators or rotors in electrical machines leads to undesirable torque and power harmonics, causing vibration, acoustic noise, and thermal issues due to circumferential gaps, which are difficult to control without affecting winding area or introducing further harmonics.
Innovation Solution
A stator design with circumferentially joined segments featuring end teeth with circumferential protrusions that differ in shape from intermediate teeth, reducing torque and power harmonics by optimizing the segment geometry to minimize gap-induced harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If segmentation is applied to ease manufacturing and transportation, then ease of manufacture is improved, but torque harmonics and power harmonics increase causing vibration and acoustic noise
Solution Approach 1:
The patent applies local quality by giving different geometries to different teeth: intermediate teeth have a first geometry while end teeth have a second geometry that differs from the first. This local differentiation allows the end teeth to compensate for the detrimental effects of segmentation gaps without affecting the winding area of intermediate slots, thus reducing torque harmonics while maintaining ease of manufacture through segmentation.
2Manufacturing precision
If the width of end slots is reduced to control gap dimensions, then manufacturing precision is improved, but winding area decreases increasing resistance and losses
Solution Approach 1:
The invention applies local quality by differentiating the geometry of end teeth from intermediate teeth. The end teeth are designed with a specific geometry that controls the circumferential gap dimensions without reducing the width of intermediate slots, thereby maintaining adequate winding area and minimizing resistance losses while achieving precise gap control.
3Reliability
If the width of final tooth is reduced to maintain winding area, then reliability is improved by eliminating hotspots, but torque harmonics increase due to uneven tooth distribution
Solution Approach 1:
The patent applies local quality by giving different geometries to different teeth: intermediate teeth maintain their standard geometry to ensure adequate winding area and uniform distribution, while end teeth are specifically designed with a different geometry to control gap dimensions. This localized differentiation eliminates hotspots in intermediate coils while using end tooth geometry to minimize torque harmonics.
4Object-generated harmful factors
If circumferential protrusions are added to end teeth, then torque harmonics are reduced, but device complexity increases
Solution Approach 1:
The patent applies local quality by introducing circumferential protrusions only on end teeth while leaving intermediate teeth with a simpler geometry. This localized modification reduces torque harmonics caused by segmentation gaps without significantly increasing overall device complexity, as the protrusions are confined to specific locations rather than requiring complex modifications throughout the entire stator structure.
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 design effectively reduces cogging and loaded torque harmonics, voltage, and power harmonics, particularly in generators connected to converters, while maintaining ease of manufacture and mechanical support for coils.
Implementation Method 1
the plurality of segments are circumferentially joined together at their ends in such a way that a segment tolerance circumferential gap is interposed between two circumferentially adjacent stator segments, wherein in order to reduce torque harmonics and power harmonics due to the interposed circumferential gap, at least one of the two end teeth of each stator segment includes a circumferential protrusion
Implementation Method 2
an electrical machine having a stator or a rotor with a segmented geometry
Data Source
AI summary
Provided is a stator for an electrical machine including a plurality of segments, whereinin order to reduce torque harmonics and power harmonics due to the interposed circumferential gap between two circumferentially adjacent stator segments,at least one of the two end teeth of each stator segment includes a circumferential protrusion at the respective tooth radial end, the circumferential protrusion protruding from the respective side face towards the respective circumferential end.