Interphase Transformer Leakage Inductance Integration

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Solution Overview

Problem

Aircraft AC to DC conversion systems, particularly those with higher pulse numbers like 18-pulse systems, require dedicated DC link chokes to reduce harmonic distortion, which increase weight, size, and cost.

Innovation Solution

The integration of additional magnetic leakage inductance within interphase power transformers by creating auxiliary magnetic paths using shunts or additional limbs with air gaps in the transformer core, eliminating the need for dedicated DC link chokes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If dedicated DC link chokes are used to reduce harmonic distortion, then power quality is improved, but weight increases

Engineering Contradiction:
Improveharmonic distortionVSAvoidweight
Core Design Contradiction:
Object-generated harmful factorsVSWeight of moving object

Solution Approach 1:

The patent combines the DC link choke function with the interphase transformer by integrating magnetic leakage paths into the transformer core structure. The interphase transformer core is designed with specific magnetic path configurations that generate the required leakage inductance, eliminating the need for separate DC link chokes while maintaining harmonic distortion reduction capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The interphase transformer is designed to perform multiple functions simultaneously: it provides phase isolation, current balancing, and DC link inductance through its magnetic leakage paths. This multi-functional design reduces the overall component count and system weight while achieving the same power quality improvement

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-generated harmful factors

If dedicated DC link chokes are used to reduce harmonic distortion, then power quality is improved, but device complexity increases

Engineering Contradiction:
Improveharmonic distortionVSAvoiddevice complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the DC link choke and interphase transformer into a single integrated component. The interphase transformer core incorporates magnetic leakage paths that provide the necessary inductance, reducing the number of separate components and simplifying the overall device structure while maintaining harmonic distortion reduction

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If dedicated DC link chokes are used to reduce harmonic distortion, then power quality is improved, but cost increases

Engineering Contradiction:
Improveharmonic distortionVSAvoidcost
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent combines two separate components (DC link choke and interphase transformer) into one integrated interphase transformer design. This reduces the total component count, assembly complexity, and material requirements, thereby lowering manufacturing cost while achieving the same harmonic distortion reduction performance

Inventive Principle:
Principle #5Merging (Combining)

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 effectively reduces harmonic distortion without the need for dedicated DC link chokes, thereby minimizing weight, size, and cost while maintaining reliability and power quality.

Implementation Method 1

means incorporated in said core so as to create auxiliary magnetic paths for flux generated by at least one of the windings, so that the magnetic flux not shared with other windings is circulated through the auxiliary magnetic path, thus integrating smoothing choke effect

Methodology Applied
Scientific EffectMagnetic leakage: Magnetic Field

Data Source

PatentEP3206287B1Autotransformer rectifier unit
Publication Date: 2019.06.05 GOODRICH CONTROL SYST LTD
  • EP3206287B1 patent drawingFigure 1
  • EP3206287B1 patent drawingFigure 2~3
  • EP3206287B1 patent drawingFigure 4~5

AI summary

The present improvement essentially integrates a DC link inductance within an interphase power transformer (IPT). The integration is achieved by creating auxiliary magnetic paths for leakage inductance inside the IPT core 50. The magnetic path can be created, for example, by incorporating extra portions of magnetic material commonly referred to hereinafter as shunts 100. The IPT flux shared between windings 60 does not cross these shunts. Therefore, this magnetic path increases the self-inductance of the IPT but does not contribute to the mutual inductance between windings. This extra magnetic path allows for leakage inductance of a much higher quantity than that achievable with a conventional IPT.