Three-Phase Power Carrier Signal Coupling Circuit

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Solution Overview

Problem

Power line communication systems face reliability issues due to noise interference and changing load conditions, leading to high installation complexity and costs, especially with conventional methods requiring multiple coupling circuits and devices for three-phase power lines.

Innovation Solution

A power carrier signal coupling circuit that uses a single phase of a three-phase AC power line as a common channel, with two power carrier signal coupling channels arranged between this phase and the other two phases, incorporating a coupling transformer and transient voltage suppressors to reduce costs and installation complexity while improving reliability by allowing data transmission through any two phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If three groups of coupling circuits or devices are used to connect master and slave devices in parallel via inductor or capacitor, then the reliability of power carrier communication is improved, but the installation complexity and cost increase

Engineering Contradiction:
Improvereliability of power carrier communicationVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines three separate coupling circuits into a single integrated coupling device that handles all three phases. The coupling device includes a coupling capacitor connected in series with the power line and a coupling inductor connected in parallel, replacing the conventional requirement for three separate coupling circuits or devices, thereby reducing installation complexity while maintaining communication reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single coupling device performs multiple functions simultaneously: it couples carrier signals for all three phases, provides impedance matching, and enables bidirectional communication. This multi-functional design eliminates the need for separate coupling circuits for each phase, reducing both device count and installation complexity

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

2Adaptability or versatility

If multiple carrier modulation circuits and receiving devices are used to couple multiple carrier signals to three phases, then data transmission capability is improved, but the cost increases

Engineering Contradiction:
Improvedata transmission capabilityVSAvoidcost
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges multiple carrier modulation circuits into a single modulation circuit that generates carrier signals for all three phases. The coupling device then distributes these carrier signals to the respective phases, eliminating the need for separate modulation circuits and receiving devices for each phase, thereby reducing system cost while maintaining full data transmission capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single modulation circuit performs the function of multiple modulation circuits by generating balanced three-phase carrier signals simultaneously. The coupling device provides universal coupling capability for all phases, enabling cost-effective multi-phase data transmission without requiring duplicate circuitry

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

3Device complexity

If a single coupling circuit is used to reduce installation complexity, then the installation cost is reduced, but the reliability of power carrier communication deteriorates due to noise interference and load variations

Engineering Contradiction:
Improveinstallation complexityVSAvoidreliability of power carrier communication
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines coupling capacitors and coupling inductors into a single integrated coupling device with specific impedance values. The coupling capacitor (e.g., 0.1μF) and coupling inductor (e.g., 1mH) are designed with precise parameters to maintain signal integrity and filter noise across all three phases, ensuring reliable communication while keeping the device count low

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling device uses specifically designed electrical parameters (capacitance value, inductance value, impedance) to optimize performance. By carefully selecting these parameters, the single coupling device can effectively handle noise interference and load variations, maintaining communication reliability without requiring multiple complex circuits

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

This configuration significantly reduces installation costs and complexity while ensuring reliable data transmission by allowing the master device to receive data via another channel in case of interference, thereby preventing information loss due to single-channel interference.

Implementation Method 1

The coupling transformer includes a primary winding, a first secondary winding and a second secondary winding. A first terminal of the first secondary winding is connected to the signal transceiver.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A first transient voltage suppressor diode. A cathode of the first transient voltage suppressor diode is connected to the common channel, and an anode of the first transient voltage suppressor diode is connected to the two phases of the three-phase AC power line other than the common channel.

Methodology Applied
Scientific EffectAvalanche breakdown: Avalanche Breakdown

Implementation Method 3

a first power carrier signal coupling channel including a first capacitor and a second power carrier signal coupling channel including a second capacitor

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3291453B1Power carrier signal coupling circuit and communication system
Publication Date: 2019.09.25 SUNGROW POWER SUPPLY CO LTD
  • EP3291453B1 patent drawingFigure 1A~2
  • EP3291453B1 patent drawingFigure 3A~3
  • EP3291453B1 patent drawingFigure 4

AI summary

Provided are a power carrier signal coupling circuit and a communication system. The power carrier signal coupling circuit includes a first power carrier signal coupling channel and a second power carrier signal coupling channel. A phase of a three-phase alternating current, AC, power line serves as a common channel, the first power carrier signal coupling channel is arranged between the common channel and one of two phases of the three-phase AC power line other than the phase of the three-phase AC power line serving as the common channel; and the second power carrier signal coupling channel is arranged between the common channel and the other of the two phases of the three-phase AC power line other than the phase of the three-phase AC power line serving as the common channel.