Galvanic Attenuation Module for Railway Harmonic Filtering

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Solution Overview

Problem

High voltage electrical systems used in railway devices and systems face challenges with bulky, heavy, and expensive harmonic attenuating filters, which are necessary to handle high voltage signals and can lead to malfunctions if not properly protected.

Innovation Solution

An electrical circuit with an attenuation module that is galvanically coupled to the circuit, using an inductive means and a high-pass filtering mechanism to induce and filter harmonic currents without being part of the main electrical path, allowing for the use of standard components that do not need to be voltage-rated, thus reducing weight, volume, and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional harmonic attenuating filter is used in high voltage electrical systems, then harmonic currents are attenuated effectively, but the filter components become bulky, heavy, and expensive

Engineering Contradiction:
Improveharmonic attenuation effectivenessVSAvoidfilter weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The filter is divided into two functionally independent parts: a galvanically isolated attenuation module for harmonic suppression and a protective device for fault current interruption. This segmentation allows the attenuation module to use lightweight, standard-rated components since it does not need to withstand high voltage, while the protective device handles only fault currents, not continuous high voltage operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A galvanic isolation interface (transformer or optocoupler) is introduced between the high voltage electrical circuit and the harmonic attenuation module. This intermediary allows the attenuation module to process harmonic currents from the high voltage system without being directly exposed to high voltage, enabling the use of low voltage-rated, lightweight components while maintaining effective harmonic suppression.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a traditional harmonic attenuating filter is used in high voltage electrical systems, then harmonic currents are attenuated effectively, but the filter components become bulky, heavy, and expensive

Engineering Contradiction:
Improveharmonic attenuation effectivenessVSAvoidfilter volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The filter is divided into two functionally independent parts: a galvanically isolated attenuation module for harmonic suppression and a protective device for fault current interruption. This segmentation allows the attenuation module to use lightweight, standard-rated components since it does not need to withstand high voltage, while the protective device handles only fault currents, not continuous high voltage operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A galvanic isolation interface (transformer or optocoupler) is introduced between the high voltage electrical circuit and the harmonic attenuation module. This intermediary allows the attenuation module to process harmonic currents from the high voltage system without being directly exposed to high voltage, enabling the use of low voltage-rated, lightweight components while maintaining effective harmonic suppression.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a traditional harmonic attenuating filter is used in high voltage electrical systems, then harmonic currents are attenuated effectively, but protection devices must be added to prevent malfunctions

Engineering Contradiction:
Improveharmonic attenuation effectivenessVSAvoidfilter complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The filter is divided into two functionally independent parts: a galvanically isolated attenuation module for harmonic suppression and a protective device for fault current interruption. This segmentation allows the attenuation module to use lightweight, standard-rated components since it does not need to withstand high voltage, while the protective device handles only fault currents, not continuous high voltage operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protective device is designed to detect and interrupt fault currents in the attenuation module automatically, isolating the defective components without requiring manual intervention. This self-protecting mechanism simplifies the overall system by integrating protection functionality directly into the filter structure, reducing the need for additional complex protection systems.

Inventive Principle:
Principle #25Self-service

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

The solution results in a lighter, less expensive, and less bulky harmonic attenuation system that does not require protective devices, effectively reducing the weight and cost of high voltage electrical circuit components while maintaining effective harmonic current elimination.

Implementation Method 1

at least one inductive means, galvanically coupled, that is to say without connection by an electric conductor, with said electric circuit, so that for each of said fundamental and harmonic currents, a proportional current of the same frequency is induced in said inductive means

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

at least one filtering means, connected in series with said inductive means, for filtering the fundamental current induced in said inductive means and allowing the induced harmonic current to pass

Methodology Applied
Scientific EffectFrequency filtering: Filter (electronic)

Data Source

PatentEP2804280B1Electrical circuit for harmonic attenuation, equipment and facility including such a circuit
Publication Date: 2020.11.04 SNCF VOYAGEURS
  • EP2804280B1 patent drawingFigure 1
  • EP2804280B1 patent drawingFigure 2

AI summary

The invention relates to an electrical circuit (110) for equipment (102), in particular railway equipment, powered by an alternating electric current, called fundamental, said electrical circuit (110) comprising at least one component (114, 116) powered by said fundamental current and generating in said electrical circuit (110) at least one undesired alternating current, called harmonic, said circuit being characterized in that it further comprises an attenuation module (120) comprising: - at least one inductive means (122), galvanically coupled with said electrical circuit (110), such that for each of said fundamental and harmonic currents, a proportional current of the same frequency is induced in said inductive means (122), and - at least one filtering means (124), connected in series with said inductive means (122), to filter the fundamental current induced in said inductive means (122) and allowing the induced harmonic current to pass.It also relates to equipment (102) comprising such a circuit (110) and an installation (100) comprising such equipment (102) and/or such a circuit (110).