Stator Tooth Recess Layout for Harmonic-Selective Electrical Machines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrical machines with fractional-slot concentrated windings, it is challenging to amplify the working wave relative to other harmonic components, including fundamental waves, while suppressing undesirable magnetomotive force components.
Innovation Solution
A stator design with single-layer winding, featuring stator teeth with recesses extending radially, is employed. This design allows for adjacent coils of the same electrical phase to be wound around teeth, with at least one unwound tooth between them, creating a mechanical barrier to reduce fundamental waves and amplify higher harmonics like the fifth or seventh harmonic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fractional-slot concentrated windings are used, then ease of manufacture and power-to-weight ratio are improved, but the fundamental waves of magnetomotive force cannot be effectively suppressed
Solution Approach 1:
The patent introduces unwound teeth at specific local positions between coils of the same phase, creating localized modifications to the stator structure. These unwound teeth act as mechanical barriers that selectively suppress fundamental waves while preserving the overall FSCW configuration and its manufacturing advantages
Solution Approach 2:
The stator teeth are segmented into wound teeth and unwound teeth, creating distinct functional zones. The unwound teeth are inserted as separate structural elements between coils of the same phase, allowing independent optimization of magnetic flux paths for different harmonic components
2Power
If higher harmonics are amplified as working wave, then power-to-weight ratio is improved, but device complexity increases due to additional stator modifications
Solution Approach 1:
The patent modifies the stator structure by changing the winding parameter - specifically introducing unwound teeth at calculated positions. This structural parameter change enables selective amplification of higher harmonics (5th or 7th) as working waves while suppressing fundamental waves, achieving improved power-to-weight ratio without complex control systems
Solution Approach 2:
The unwound teeth are pre-positioned in the stator structure during manufacturing, before the machine operates. This preliminary structural configuration pre-establishes the magnetic flux paths that will selectively amplify desired harmonics and suppress unwanted ones during operation, eliminating the need for active control
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 stator design effectively amplifies the chosen harmonic while significantly reducing the fundamental waves, improving the power-to-weight ratio and fault tolerance of the electrical machine.
Implementation Method 1
a recess which extends substantially in the radial direction and is arranged in the tooth region... the recess forms a mechanical barrier to reduce the fundamental waves of the magnetic flux
Implementation Method 2
the additional recess in the tooth area amplifies the working wave, for example the fifth or seventh harmonic of the magnetomotive force
Data Source
AI summary
A stator (1) for an electrical machine comprises a plurality of stator teeth distributed along the circumference of the stator and with slots (2) formed between each of them. Coils of the same electrical phase (U, V, W) are arranged adjacent to each other and wound around respective teeth (3). At least one unwound tooth (4) is provided between the adjacent coils of the same electrical phase. The teeth (3) wound with adjacent coils of the same electrical phase each have a recess (5) which extends substantially in the radial direction and is arranged in the tooth region, or the at least one unwound tooth (4) each has a recess (5) which extends substantially in the radial direction and is arranged in the tooth region.