Coupled Output Inductor Shielding for Stable Leakage Inductance

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Solution Overview

Problem

Existing power converters with coupled output inductors suffer from degraded performance due to significant variations in current ripple caused by proximity to conductive materials, leading to increased magnetic field emissions and erroneous behavior in nearby circuitry.

Innovation Solution

Surrounding the coupled output inductor with high-permeability material to create a controlled magnetic path for leakage flux, reducing interaction with conductive materials and enhancing leakage inductance while minimizing magnetic field emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the coupled output inductor is placed close to conductive materials to reduce size, then the overall power converter size is reduced, but the effective leakage inductance is reduced by 50% or more causing high ripple current

Engineering Contradiction:
Improvepower converter sizeVSAvoidcurrent ripple stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

A non-conductive spacer is introduced as an intermediary element between the coupled output inductor and the conductive case. This spacer maintains the compact physical arrangement for size reduction while preventing the harmful interaction that would reduce leakage inductance, thereby preserving current ripple stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The non-conductive spacer is a simple, inexpensive component that provides a permanent solution to the inductance variation problem. It is a basic insulating element that requires no maintenance or replacement, effectively blocking magnetic flux interaction with the conductive case.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Volume of moving object

If the coupled output inductor is placed close to conductive materials, then the overall power converter size is reduced, but magnetic field emissions increase causing erroneous behavior in nearby circuitry

Engineering Contradiction:
Improvepower converter sizeVSAvoidmagnetic field emissions
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The non-conductive spacer acts as a magnetic isolation barrier between the inductor and the conductive case. By inserting this intermediate layer, the magnetic flux generated by the inductor is prevented from coupling with the conductive materials, thereby reducing radiated emissions and electromagnetic interference with nearby circuitry while maintaining compact size.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach provides immunity to nearby conductive materials, reduces magnetic field emissions, and achieves higher inductance with lower losses, enabling smaller, more efficient power converters with improved power density.

Implementation Method 1

provides a high-permeability path for leakage flux by surrounding a coupled output inductor with high relative permeability material

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Data Source

PatentEP3770928B1Coupled output inductor and system
Publication Date: 2023.10.11 ROCKWELL COLLINS INC
  • EP3770928B1 patent drawingFigure 1
  • EP3770928B1 patent drawingFigure 2A~2B
  • EP3770928B1 patent drawingFigure 3

AI summary

A system may include a coupled output inductor. The coupled output inductor may include a ferromagnetic core, wire wrapped around the ferromagnetic core, and at least one ferromagnetic path for control of leakage flux. The leakage flux may be at least mostly contained within the at least one ferromagnetic path.