Rail Track Occupancy Detection Using Matching Coil Inductance

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Solution Overview

Problem

Short track circuits suffer from reduced sensitivity and quality in rail vehicle detection due to decreased inductance and increased losses, while long circuits face sensitivity issues from weather and fuzzy occupancy detection, leading to unreliable messages.

Innovation Solution

Incorporating a matching coil arrangement between the rails, which can be designed as extension or shortening coils, to enhance inductance and resonant resistance, thereby increasing sensitivity and reliability of rail vehicle detection across varying track lengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the track circuit length is reduced, then the device complexity is reduced, but the inductance decreases and losses increase, reducing detection sensitivity

Engineering Contradiction:
Improvetrack circuit lengthVSAvoiddetection sensitivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

A matching coil arrangement is introduced as an intermediary component between the capacitor and the rails. This matching coil acts as a mediator that compensates for the reduced inductance in short track circuits by adding its own inductance, thereby maintaining detection sensitivity without requiring longer track circuits.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The matching coil arrangement changes the electrical parameters of the resonant circuit by adding inductance and resonant resistance. This parameter modification allows the circuit to maintain optimal detection characteristics across different track lengths, effectively decoupling detection sensitivity from track circuit length.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the track circuit length is increased, then the inductance increases, but the capacitance becomes relatively small, increasing weather sensitivity

Engineering Contradiction:
Improvedetection sensitivityVSAvoidweather sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The matching coil arrangement modifies the electrical parameters of the resonant circuit, specifically increasing the resonant resistance. This parameter change counteracts the relative decrease in capacitance in long track circuits, reducing weather sensitivity while maintaining detection sensitivity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the track circuit length is increased, then the inductance increases, but the occupancy detection points become indistinct, reducing measurement precision

Engineering Contradiction:
Improveoccupancy detection precisionVSAvoidtrack circuit length
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The matching coil arrangement creates local electromagnetic field conditions that enhance the distinctness of occupancy detection points. By concentrating the magnetic field in specific regions through the matching coil, the system achieves better spatial resolution for detecting train positions within long track circuits.

Inventive Principle:
Principle #3Local quality

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 matching coil arrangement significantly improves the detection sensitivity and quality for both short and long track circuits, reducing losses and occupancy blur, enabling reliable occupancy and vacancy reporting.

Implementation Method 1

the matching coil arrangement consists of at least one matching coil which is inserted in a compartment of the track section formed with the galvanic bridges on both sides and is connected on one side to a rail-free connection of the capacitor with a one-sided connection to one rail and on the other side to the other rail

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

the resonant circuit is designed as a parallel resonant circuit... it is possible to detect a resulting change in damping and resonance frequency while a rail vehicle is traversing the track section

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3397537B1Assembly for monitoring the occupancy state of a switch or a track region
Publication Date: 2020.01.29 SIEMENS MOBILITY GMBH
  • EP3397537B1 patent drawingFigure 1~2
  • EP3397537B1 patent drawingFigure 3~4
  • EP3397537B1 patent drawingFigure 5~6

AI summary

The invention relates to an assembly (1) for monitoring the occupancy state of a switch or a track region, comprising a track section (3) which is designed as a resonant circuit (2). The resonant circuit (3) contains a rail (4) and an additional rail (5) of the track section (3) with a galvanic bridge (6, 7) on both sides and a capacitor (8) arranged between the rails (4, 5). The aim of the invention is to optimize the detection behavior for such an assembly while taking into consideration different lengths of the assembly. This is achieved in that the assembly (1) has at least one adaptation coil assembly (13, 14) which is placed in a track section (3) compartment (11) formed by the galvanic bridges (6, 7) on both sides and which is connected to a rail-free connection (12) of the capacitor (8) with a single-sided connection to one rail (4) on one side and to the other rail (5) on the other side.