Segmented Stator Core Aligning Grain-Oriented Steel

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Solution Overview

Problem

Stators made from grain-oriented electrical steel experience increased magnetic losses in alternating current or three-phase motors due to deviations in the direction of magnetic flux from the preferred orientation of the grain-oriented electrical steel, leading to poorer magnetic properties compared to non-grain-oriented steel stators.

Innovation Solution

A stator design featuring a winding made of grain-oriented electrical steel aligned with a deviation angle of at most ±25° from the circumferential direction of the stator core, minimizing magnetic losses by optimizing the alignment of the grain-oriented electrical steel to match the circumferential direction, and potentially including multiple layers for enhanced efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If grain-oriented electrical steel is used for sheet metal blanks, then magnetic permeability is improved in the preferred direction, but magnetic losses increase when magnetic flux deviates from this direction

Engineering Contradiction:

Improvemagnetic lossesVSAvoidmagnetic properties in yoke area

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The stator core is divided into multiple individual segments (typically 3-12 segments) arranged radially around the receiving opening. Each segment is made from grain-oriented electrical steel with its preferred direction oriented radially. This segmentation allows the magnetic flux to follow the preferred direction in each segment while the overall circular arrangement maintains continuous magnetic paths in the yoke area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a conventional single-piece or few-piece stator core to a multi-segment radial arrangement. By organizing segments in a radial pattern around the receiving opening, the patent creates a new dimensional configuration where the preferred grain direction of each segment aligns with the radial magnetic flux, while the circular arrangement provides continuous circumferential paths.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If sheet metal blanks are assembled from individual segments, then grain-oriented electrical steel can be used with preferred direction within 25° of radial direction, but manufacturing complexity increases

Engineering Contradiction:

Improvemagnetic permeabilityVSAvoidstator assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The individual segments serve multiple functions simultaneously: they conduct magnetic flux in the radial direction through their tooth-like projections, form the yoke area when assembled in a circle, and provide mechanical support for the stator structure. This multi-functionality reduces the need for additional separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Significantly reduces magnetic losses and core losses, improving the overall efficiency and stability of the electric motor while maintaining superior magnetic permeability, with optimal efficiency achieved when the preferred direction of the winding aligns closely with the circumferential direction of the stator.

Implementation Method 1

the magnetic flux then flows with a maximum deviation of less than 25° in the direction of the preferred direction of the grain-oriented sheet metal

Methodology Applied

Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

grain-oriented electrical steel has a particularly high permeability in a preferred direction

Methodology Applied

Scientific EffectPermeability: Dielectric Permittivity

Implementation Method 3

increased losses occur in all directions deviating from this

Methodology Applied

Scientific EffectMagnetic losses: Magnetic Hysteresis

Data Source

PatentEP3783771A1Stator of an electric motor and method for manufacturing the same

Publication Date: 2021.02.24 THYSSENKRUPP ELECTRICAL STEEL GMBH

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AI summary

The invention relates to a stator for an electric motor, wherein the stator (1) comprises a stator core (2) formed by a stack of sheet metal blanks (3) made of grain-oriented electrical steel, wherein the stator (1) defines a receiving opening (4) intended for receiving a rotor of the electric motor, and wherein tooth-like projections are present on the inside of the sheet metal blanks (3) associated with the receiving opening (4), which are arranged at regular angular intervals around the center of the receiving opening (4) and converge from a radial direction (R) towards the center of the receiving opening (4).In order to optimize the benefits of using grain-oriented electrical steel for the sheet blanks forming the stator (1) in such a stator (1) using simple means, the invention proposes that a winding, also consisting of grain-oriented electrical steel, is placed around the stator core (2), wherein the preferred direction (VW) in which the grains of the grain-oriented electrical steel from which the winding is formed are aligned deviates by a deviation angle (β) of at most ± 25° from the circumferential direction (U) of the stator core (2).