Inductive Coupling via Di/dt Modulation for Subsea Data Integrity

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Solution Overview

Problem

Subsea component communication technologies face challenges with signal corruption due to temperature and age-related drift in inductive coupling, high costs and corrosion issues with wet-matable connectors, and susceptibility to RF interference in far-field communications.

Innovation Solution

The use of near-field magnetic induction using ∂i/∂t circuits with inductive transmission and receive coils, optimized for variable baud rates and protocols like RS-485, and configured for full duplex operation, minimizes external interference and maintains data integrity in harsh environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If far-field RF communication is used, then communication range is extended, but susceptibility to RF interference and signal corruption increases

Engineering Contradiction:
Improvecommunication rangeVSAvoidRF interference susceptibility
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The system uses feedback mechanisms where the receiver detects signal quality and adjusts transmission parameters, and the transmitter monitors received signal strength to optimize communication. This feedback loop enables the system to maintain reliable communication by adapting to changing conditions and rejecting interference.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs parameter changes by dynamically adjusting transmission frequency, power level, and modulation scheme based on channel conditions. The system can switch between different RF parameters to avoid interference and maintain communication quality across varying environmental conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If inductive coupling with carriers and tuned circuits is used, then data transmission is achieved, but drift and signal corruption occur over temperature and age

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidfrequency stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system incorporates frequency tracking and calibration circuits that continuously monitor and adjust carrier frequency to compensate for drift. Feedback loops detect frequency deviations caused by temperature or aging and automatically correct them, maintaining stable communication over the device lifetime.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses temperature-compensated oscillators and adjustable frequency synthesis that adapt the carrier frequency based on environmental conditions. By changing operating parameters dynamically, the system compensates for component drift and maintains frequency stability across temperature ranges and aging.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If wet-matable connectors are used, then physical connection is achieved, but cost increases and corrosion issues arise

Engineering Contradiction:
Improveconnection reliabilityVSAvoidcorrosion susceptibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical wet-matable connectors with contactless RF inductive coupling. This substitution eliminates physical contact between components, thereby preventing corrosion while maintaining reliable data transmission through electromagnetic field coupling across an air gap.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If wet-matable connectors are used, then physical connection is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system replaces expensive precision mechanical connectors with simpler RF inductive coupling interfaces. This substitution reduces manufacturing costs by eliminating complex mechanical assemblies, precision machining requirements, and specialized connector components while maintaining connection reliability through contactless coupling.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reliable, high-speed data transmission with immunity to external electrical and RF interference, suitable for a wide range of environments including subsea, while reducing costs and corrosion risks.

Implementation Method 1

near-field magnetic induction using di/dt circuits with inductive transmission and receive coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

hysteresis

Methodology Applied
Scientific EffectMagnetic hysteresis: Magnetic Hysteresis

Data Source

PatentEP2944030B1Wireless data transmission via inductive coupling using di/dt as the magnetic modulation scheme and hysteresis
Publication Date: 2020.02.19 OCEANEERING INTERNATIONAL INC
  • EP2944030B1 patent drawingFigure 1
  • EP2944030B1 patent drawingFigure 2
  • EP2944030B1 patent drawingFigure 3

AI summary

The disclosed couplers operate in a "near field" mode, meaning energy, whether used to transmit data or power, is transferred through magnetic induction using a di/dt circuit (meaning a change in current over a change in time), such as by using inductive transmission and receive coils in which resistors and/or other components such as diodes are placed into series and/or in parallel with the coils and used to control the shape of the pulse, e.g. its voltage and/or frequency. In an embodiment, one connector comprises a voltage comparator which comprises a hysteresis circuit adapted to be centered at a predetermined no pulse voltage for use in data transmission.