Power Adapter PLC Data Transmission via Mains Feedback Loop

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Solution Overview

Problem

The existing Power Line Communication (PLC) systems face challenges with bulky and inflexible Ethernet cables, high thermal stress due to integrated PLC modules, and the need for additional wires for synchronization and power supply, which complicates installation and increases costs and risks of signal degradation.

Innovation Solution

The PLC circuits are remotely located in the equipment, with the PLC modulation, zero crossing detection signal, and low voltage power supply transmitted over a single low voltage power cord, using a modified power supply converter feedback loop to inject a sinusoidal signal derived from the mains voltage, allowing extraction of the necessary signals in the equipment for sequencing and data modulation/demodulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If PLC circuits are integrated into the mains unit, then data transmission is enabled, but thermal stress increases and cooling becomes difficult

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidthermal stress
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The system is divided into two separate units: a mains unit containing the power supply and a remote unit containing the PLC circuits. This segmentation allows the PLC circuits to be physically separated from the heat-generating power supply, reducing thermal stress while maintaining data transmission functionality through the power line connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power line itself serves as an intermediary medium that carries both power and data signals. By using the existing power infrastructure as a communication channel, the system enables data transmission without requiring separate communication hardware in the mains unit, thus reducing thermal load while maintaining adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If Ethernet cable is used for data transmission, then reliable communication is achieved, but installation becomes cumbersome and costs increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidinstallation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The power line is made multi-functional by enabling it to carry both electrical power and data communication signals simultaneously. This eliminates the need for separate Ethernet cabling infrastructure, simplifying installation while maintaining reliable communication through the existing power distribution network.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The power supply and data communication functions are merged into a single integrated system using the power line as a common medium. By combining these functions, the system reduces the number of required cables and connectors, making installation easier and reducing points of failure.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If additional wires are added for synchronization and power supply, then signal accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidwiring complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The power line is utilized as a multi-functional medium that simultaneously provides power delivery, data transmission, and synchronization signals. By embedding the zero-crossing detection and PLC communication within the existing power infrastructure, the system achieves accurate synchronization without requiring additional dedicated wiring.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the power line's own characteristics (such as its AC waveform and zero-crossing points) to provide synchronization information. This self-service approach extracts necessary timing signals from the power supply itself, eliminating the need for separate synchronization wiring while maintaining signal accuracy.

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

This solution eliminates the need for a separate digital data transmission cable, reduces the size and thermal stress of the mains unit, and ensures efficient cooling of PLC circuits, while maintaining the advantages of a separate mains unit, such as reduced size, heat release, and safety.

Implementation Method 1

by modulating one or more carriers in a frequency band usually located in the 2-30 MHz range

Methodology Applied
Scientific EffectModulation: Phase Modulation

Implementation Method 2

These signals are generally conveyed via a transformer isolating the low voltage part comprising the digital circuits and the CPL modulation/demodulation circuits from the dangerous high voltage part of the electrical network

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a power supply converter making it possible to transform the alternating voltage from the mains into a direct voltage

Methodology Applied
Scientific EffectRectification and voltage conversion:

Implementation Method 4

the feedback loop ensuring the regulation of the power supply converter by reinjecting, superimposed on the feedback loop setpoint voltage, a signal derived from the mains voltage

Methodology Applied
Scientific EffectFeedback control: Feedback

Data Source

PatentEP2400668B1Device/power adapter assembly with data transmission by powerline communication PLC
Publication Date: 2012.07.18 FREEBOX
  • EP2400668B1 patent drawingFigure 1~3
  • EP2400668B1 patent drawingFigure 4~5c
  • EP2400668B1 patent drawingFigure 6~7

AI summary

The assembly has an alternating current-direct current chopping converter (32) including a feedback loop in which a fraction of direct voltage is applied as setpoint voltage at input of an interruption control circuit. A sector block (10) has an additional zero crossing signal detection circuit (36) that is coupled with a sector line at its input and with the loop at its output, to reinject derivative signal of alternating voltage from the sector line. A synchronization circuit (46) has a pulse extractor circuit that is coupled with a low voltage power supply conductor (16) at its input. The chopping converter is chosen from a group comprising a half-bridge converter, a full-bridge converter, a push-pull converter, a forward converter and a flyback converter.