Coupling Coil Structure for Scott Transformer Leakage Impedance

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Solution Overview

Problem

The existing coupling coil structure in Scott-connected transformers requires division of the main-phase secondary coil into multiple coils connected in parallel, increasing production time and effort, and results in a larger transformer size and weight due to reduced space factor and increased conductor turns.

Innovation Solution

A coupling coil structure where a single sheet-shaped conductor, such as a thin metal plate, is wound around the iron core to form the main-phase secondary coil, allowing mutual induction with primary coils, and lead wires serve as terminals, eliminating the need for multiple coils and reducing conductor turns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the main-phase secondary coil is divided into multiple coils connected in parallel to form a coupling coil, then the leakage impedance between primary coils is reduced, but the production time and effort increase

Engineering Contradiction:
Improveleakage impedanceVSAvoidproduction time and effort
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The patent divides the main-phase secondary coil into multiple coils (U-side and W-side coils) that are connected in parallel. This segmentation allows each coil to be positioned adjacent to specific primary coils, improving magnetic coupling and reducing leakage impedance between the primary coils while maintaining overall functionality.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If the main-phase secondary coil is divided into multiple coils, then the leakage impedance between primary coils is reduced, but the transformer size and weight increase

Engineering Contradiction:
Improveleakage impedanceVSAvoidtransformer weight
Core Design Contradiction:
Object-generated harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent positions the divided secondary coils in a spatial arrangement where the U-side secondary coil is adjacent to the U-side primary coil and the W-side secondary coil is adjacent to the W-side primary coil. This dimensional arrangement optimizes magnetic coupling in space, reducing leakage impedance without requiring additional transformer volume or weight.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration enhances productivity by simplifying coil formation, reduces the transformer's size and weight, and improves magnetic coupling between primary coils, thereby efficiently lowering leakage impedance.

Implementation Method 1

mutual induction occurs between the main-phase primary coil 12 and the main-phase secondary coil 14 and between the teaser primary coil 13 and the teaser secondary coil 15

Methodology Applied
Scientific EffectMutual induction: Electromagnetic Induction

Data Source

PatentEP3054464B1Coupling coil structure and transformer
Publication Date: 2021.01.20 TOSHIBA IND PROD & SERVICES CORP
  • EP3054464B1 patent drawingFigure 1
  • EP3054464B1 patent drawingFigure 2
  • EP3054464B1 patent drawingFigure 3

AI summary

The coupling coil structure, which is provided with a plurality of primary coils formed by winding a conductor wire and a plurality of secondary coils provided so as to generate mutual inductance with the plurality of primary coils and in which, among the plurality of primary coils, one primary coil is tapped at an intermediate portion thereof by another primary coil at right angles, is characterized in that, among the plurality of secondary coils, a secondary coil in mutual inductance with the one primary coil is constituted into a coupling coil by one conductor having a width at least the size in the axial direction of the primary coil.