Transformer Sensor Cable Peaking Correction

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Solution Overview

Problem

Differential transformer-based sensors in aircraft systems face accuracy issues due to cable peaking caused by capacitance in long sensor cables, which can introduce errors at resonance frequencies, pushing the sensor data out of specified tolerances, especially in high-accuracy applications.

Innovation Solution

A cable peaking correction apparatus is integrated into the signal processing system, allowing for adjustment of the excitation frequency or capacitance to ensure that the sensor operation remains within tolerances by shifting the resonant frequency away from the excitation frequency, using a method that tunes the cable peaking correction component to prevent data errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If long sensor cables are used in transformer based sensors, then the sensor can be installed at greater distances from the signal processing system, but cable capacitance introduces resonance frequency peaks that interfere with signal transmission and push sensor data out of specified tolerances

Engineering Contradiction:
Improvecable lengthVSAvoidsensor data accuracy
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent adjusts electrical parameters (capacitance or excitation frequency) of the sensor arrangement to shift the resonance frequency away from the excitation frequency. This parameter change eliminates the harmful resonance peak while maintaining the ability to use long cables, thus preserving both installation flexibility and measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Power

If the excitation frequency is set close to the resonance frequency for optimal signal transmission, then signal strength is maximized, but cable peaking occurs causing signal interference and measurement errors

Engineering Contradiction:
Improvesignal strengthVSAvoidcable peaking interference
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the excitation frequency parameter to be deliberately offset from the resonance frequency. This parameter change prevents cable peaking and signal interference while maintaining sufficient signal strength for accurate measurement, thus resolving the contradiction between signal strength and harmful interference.

Inventive Principle:
Principle #35Parameter changes

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 effectively corrects for cable peaking, ensuring accurate position sensing by maintaining the sensor data within specified tolerances, even in applications requiring high precision, by adjusting the excitation frequency or capacitance to avoid resonance-induced errors.

Implementation Method 1

The shift in position of the coils or the core affects the output of the sensor in a known manner, allowing the controller to detect the output and calculate the position of the actuator.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

It is known in the art that RLC circuits include a cable resonance frequency resulting in a signal peak at the resonant frequency. If information is transmitted at, or close to, the resonance frequency, the peak can interfere with the information transmitted.

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2765391B1Transformer based sensor arrangement
Publication Date: 2019.04.03 HAMILTON SUNDSTRAND CORP
  • EP2765391B1 patent drawingFigure 1
  • EP2765391B1 patent drawingFigure 2~3
  • EP2765391B1 patent drawingFigure 4~5

AI summary

A position sensor arrangement, 300, 400, has a transformer based position sensor, 310, 410, and a cable peaking correction apparatus, 340, 440. The cable peaking correction apparatus, 340, 440, is coupled to at least one of a transformer based position sensor excitation input and the plurality of outputs from the transformer based position sensor, 310, 410.