EMI Mitigation via Common-Mode Filter and Adjacent Cable

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Solution Overview

Problem

Existing common-mode noise filtering technologies are inadequate for aerospace applications due to increased weight, size, and cost, and fail to provide sufficient attenuation of common-mode noise in volume and weight-constrained environments.

Innovation Solution

A device comprising an unshielded cable with an adjacent attenuation cable and a clamp-on core, along with a common-mode filter, provides an alternate path for common-mode currents, eliminating the need for a cable shield and reducing weight while effectively attenuating common-mode noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If multiple filter assemblies are used in series to achieve desired filtering, then common-mode noise attenuation is improved, but weight and size of the filter assembly increase

Engineering Contradiction:

Improvecommon-mode noise attenuationVSAvoidfilter assembly weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent combines multiple filtering functions into a single integrated filter assembly. The common-mode filter and differential-mode filter are merged into one unit, eliminating the need for separate filter assemblies connected in series. This integration maintains effective common-mode noise attenuation while significantly reducing the overall weight and size of the filtering system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The filter assembly is designed to perform multiple functions simultaneously - it provides both common-mode noise filtering and differential-mode noise filtering through a single device. The filter incorporates both common-mode chokes and differential-mode filtering elements that work together in one assembly, making it universally effective against multiple types of electromagnetic interference without requiring additional separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If multiple filter assemblies are used in series to achieve desired filtering, then common-mode noise attenuation is improved, but size of the filter assembly increases

Engineering Contradiction:

Improvecommon-mode noise attenuationVSAvoidfilter assembly size

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If cable shield is used to attenuate common-mode noise, then noise attenuation is improved, but weight of the cable assembly increases

Engineering Contradiction:

Improvecommon-mode noise attenuationVSAvoidcable assembly weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent extracts the common-mode filtering function from the cable shield and implements it through a separate common-mode filter with choke coils. Instead of relying on the cable shield to provide common-mode attenuation, the design removes this function and assigns it to a dedicated filter component, allowing the use of lighter unshielded or partially shielded cables while maintaining effective common-mode noise suppression.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The common-mode filter acts as an intermediary component between the cable and the noise source. Rather than depending on the cable shield to block common-mode currents, the filter provides a controlled path for these currents through its choke coils, effectively attenuating common-mode noise while allowing the cable structure to be optimized for reduced weight.

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 solution achieves significant attenuation of common-mode noise with reduced weight and environmental impact, offering improved performance and reliability in aerospace applications.

Implementation Method 1

a second cable coupled between the source and the load and disposed adjacent to the first cable. The second cable is configured to provide common-mode noise attenuation by providing an alternate path for a common-mode current to flow

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a common-mode filter coupled to the un-shielded cable wherein at least one of the attenuation cable, the clamp-on core and the common-mode filter is configured to mitigate a common-mode noise

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Data Source

PatentUS8324980B2Electromagnetic interference mitigation system and method

Publication Date: 2012.12.04 GENERAL ELECTRIC CO

AI summary

A device to attenuate EMI between a source and a load is provided. The device includes a first cable to electrically couple the source and the load and a second cable positioned adjacent to the first cable and configured to attenuate a common-mode current.