Photovoltaic Module Safety Circuit Segmentation

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Solution Overview

Problem

Existing photovoltaic systems lack safe and controlled switching mechanisms for handling electrical faults, maintenance, and startup procedures, posing risks due to high voltages and the inability to disconnect faulty components safely.

Innovation Solution

A method and system for detecting electrical faults in photovoltaic systems by measuring and analyzing voltage and current curves, distinguishing between operating, fault, and safety states, and using intelligent solar modules with safety circuits to securely disconnect and reconnect modules, ensuring safe operation and minimal downtime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If solar modules are connected in series to form strings to achieve high voltage, then the power output is improved, but the safety risk increases due to dangerous voltages of several 100 V or even 1000 V

Engineering Contradiction:
Improvepower outputVSAvoidsafety risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The system divides the string into individually controllable solar modules, each with its own safety circuit. This segmentation allows the string to maintain high voltage for power generation while enabling isolated disconnection of individual modules or groups to mitigate safety risks during faults or maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The safety circuits are pre-configured in each solar module to enable rapid disconnection upon fault detection. This preliminary preparation ensures that when a fault occurs, the system can immediately isolate affected sections without requiring manual intervention, thus reducing safety risks while maintaining high voltage operation during normal conditions.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If simple junction boxes are used without special safety precautions, then the device complexity is reduced, but the ability to disconnect faulty components is lost

Engineering Contradiction:
Improvedevice complexityVSAvoidability to disconnect faulty components
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

Each solar module is equipped with an integrated safety circuit that automatically detects faults and disconnects the module from the string without external intervention. This self-service capability maintains operational simplicity while providing the necessary fault isolation functionality, avoiding the need for complex external safety systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The safety circuit is designed as a universal component that can be integrated into any solar module within the string. This multi-functional approach combines power generation, monitoring, and safety disconnection capabilities in a single standardized unit, maintaining device simplicity while enabling selective disconnection of faulty components.

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

3Object-affected harmful factors

If the entire string is switched off when a fault is detected, then the safety is improved, but the productivity is reduced due to complete system shutdown

Engineering Contradiction:
ImprovesafetyVSAvoidproductivity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system isolates faults to the individual solar module or minimal affected group rather than shutting down the entire string. This segmentation enables continued operation of healthy modules, maintaining productivity while ensuring safety by disconnecting only the faulty portion from the high-voltage string.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The safety response is applied locally to the affected solar module rather than globally to the entire string. Each module's safety circuit independently manages its own disconnection, allowing other modules to continue generating power. This local quality approach preserves overall system productivity while addressing safety concerns in the specific affected area.

Inventive Principle:
Principle #3Local quality

4Device complexity

If manual switching procedures are used for maintenance and faults, then the device complexity is reduced, but the time required for switching operations increases

Engineering Contradiction:
Improvedevice complexityVSAvoidswitching operation time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The safety circuits automatically detect faults and execute disconnection operations without requiring manual intervention. This self-service capability eliminates the time-consuming manual switching procedures while maintaining simple device architecture, as the automatic response is built into the basic safety circuit functionality of each module.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The safety circuits continuously monitor electrical parameters and provide feedback to detect fault conditions. This automatic feedback mechanism triggers immediate disconnection when faults are detected, eliminating the delay associated with manual detection and switching operations, while the overall device complexity remains low due to the straightforward monitoring and response logic.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2954340B1Safe photovoltaic system
Publication Date: 2020.03.18 PHOENIX CONTACT GMBH & CO KG
  • EP2954340B1 patent drawingFigure 1~11
  • EP2954340B1 patent drawingFigure 2~3
  • EP2954340B1 patent drawingFigure 4

AI summary

The invention provides a fault detection system in a photovoltaic system (1), which uses a first measurement characteristic curve and optionally a second measurement characteristic curve to record the system status, and can thus distinguish malfunctions from the normal system operating state.