Coupling Transformer Arc Fault Detection Inverter

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Solution Overview

Problem

Current inverter designs for photovoltaic plants are complex and expensive due to the need for compact arrangement of protection devices like arc fault detection and shutdown control devices at the DC stage, especially with many electric lines involved.

Innovation Solution

The use of a single coupling transformer with magnetically coupled winding arrangements to facilitate AC signal transmission for arc fault detection and shutdown control, integrating these functions into compact circuit structures within the DC stage of the inverter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separate protection devices are installed for arc fault detection and shutdown control, then the reliability of the photovoltaic plant is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveprotection device reliabilityVSAvoidDC stage complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines arc fault detection and shutdown control functions into a single integrated coupling transformer. The first winding arrangement handles arc fault detection by sensing AC currents, while the second winding arrangement handles shutdown control by injecting control signals. This merging reduces the number of separate devices needed and simplifies the overall DC stage architecture while maintaining both protection functions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling transformer is designed as a multi-functional device that simultaneously performs arc fault detection and shutdown control operations. By incorporating both winding arrangements in a single transformer structure, the device achieves universal functionality that eliminates the need for separate dedicated devices, thereby reducing complexity while preserving reliability

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

2Reliability

If multiple separate protection devices are installed for arc fault detection and shutdown control, then the reliability of the photovoltaic plant is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveprotection device reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines arc fault detection and shutdown control functions into a single integrated coupling transformer. The first winding arrangement handles arc fault detection by sensing AC currents, while the second winding arrangement handles shutdown control by injecting control signals. This merging reduces the number of separate devices needed and simplifies the overall DC stage architecture while maintaining both protection functions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling transformer is designed as a multi-functional device that simultaneously performs arc fault detection and shutdown control operations. By incorporating both winding arrangements in a single transformer structure, the device achieves universal functionality that eliminates the need for separate dedicated devices, thereby reducing complexity while preserving reliability

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

3Device complexity

If a single coupling transformer is used to integrate arc fault detection and shutdown control functions, then the device complexity is reduced, but the measurement precision of arc fault detection may be affected

Engineering Contradiction:
ImproveDC stage complexityVSAvoidarc fault detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The coupling transformer is segmented into distinct winding arrangements: the first winding arrangement is dedicated to arc fault detection with its own signal processing path, while the second winding arrangement is dedicated to shutdown control. This segmentation within the integrated structure ensures that each function has its own dedicated components, maintaining measurement precision for arc fault detection while achieving overall device integration

Inventive Principle:
Principle #1Segmentation

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 simplifies the design and reduces costs by enabling efficient integration of arc fault detection and shutdown control functions, allowing for easier and more economical production of the inverter's DC stage while ensuring safe operation of the photovoltaic plant.

Implementation Method 1

a single coupling transformer operatively coupled with said electric lines. Said coupling transformer comprises a first winding arrangement and a second winding arrangement magnetically coupled one with another

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3647797A1An inverter comprising means for detecting arcing faults in the DC section of a photovoltaic plant
Publication Date: 2020.05.06 FIMER
  • EP3647797A1 patent drawingFigure 1
  • EP3647797A1 patent drawingFigure 2
  • EP3647797A1 patent drawingFigure 3

AI summary

An inverter (1) for a photovoltaic plant (100), said inverter comprising one or more DC electric lines (30) electrically connectable to corresponding photovoltaic strings (20) of said photovoltaic plant. Each DC electric line comprises a plurality of line conductors (31, 32), characterised in that it comprises a coupling transformer (4) having a first winding arrangement (5) and a second winding arrangement (6) magnetically coupled one with another. Said first winding arrangement comprises one or more first winding conductors (51) electrically connected with one or more line conductors (31, 32) of a corresponding electric line. Said second winding arrangement comprises one or more winding conductors (62, 63) magnetically coupled with said first winding conductors and it is adapted to provide first signals (DS) indicative of AC currents flowing along said DC electric lines (30) and to exchange second signals (CS, TS) along the line conductors (31, 32) of said DC electric lines (30) by exploiting the magnetic coupling with said first winding arrangement.