Solar Module Integrated Switch for DC De-energization

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Solution Overview

Problem

Photovoltaic systems pose a risk of high-voltage electric shocks during fires or maintenance due to the presence of DC voltage after disconnection from the AC grid, requiring complex and robust communication systems to ensure safety.

Innovation Solution

Integration of a switch and sensor within the solar module to periodically scan the connection status and switch the output connection between voltage-free and non-voltage-free states, using a self-sufficient power supply and a switching algorithm to maintain safety without frequent interruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a switch is provided on the roof to disconnect modules from the grid during fires, then safety against high-voltage electric shocks is improved, but device complexity and communication requirements increase

Engineering Contradiction:
Improvesafety against high-voltage electric shocksVSAvoidcommunication system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solar module autonomously monitors its own connection status through integrated sensors and switches. The module independently detects whether it is connected to the grid or in island mode, and automatically activates the switch to disconnect DC output when necessary, without requiring external control signals or complex communication infrastructure.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The safety function is distributed to individual solar modules rather than centralized in a single control system. Each module contains its own sensor, switch, and control logic, allowing independent operation and eliminating the need for complex inter-module communication networks.

Inventive Principle:
Principle #1Segmentation

2Reliability

If constant communication between inverter and switch is implemented, then system control and safety monitoring are improved, but robustness requirements and operational complexity increase

Engineering Contradiction:
Improvesystem control and safety monitoringVSAvoidoperational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solar module autonomously monitors its own connection status through integrated sensors and switches. The module independently detects whether it is connected to the grid or in island mode, and automatically activates the switch to disconnect DC output when necessary, without requiring external control signals or complex communication infrastructure.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The sensor periodically scans the connection status at defined intervals rather than requiring continuous communication. This periodic monitoring approach reduces operational complexity while maintaining adequate safety monitoring, allowing the system to function with simple, intermittent checks rather than constant communication overhead.

Inventive Principle:
Principle #19Periodic action

3Ease of operation

If the switch is activated only upon receiving signals from the inverter, then centralized control is maintained, but response time and safety during fires may be delayed

Engineering Contradiction:
Improvecentralized controlVSAvoidresponse time during fires
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The sensor continuously or periodically monitors connection status in advance, and the switch is pre-positioned to can immediately disconnect DC output when island mode is detected. This eliminates delays associated with waiting for inverter signals during emergency situations like fires.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The safety function is distributed to individual solar modules rather than centralized in a single control system. Each module contains its own sensor, switch, and control logic, allowing independent operation and eliminating the need for complex inter-module communication networks.

Inventive Principle:
Principle #1Segmentation

4Reliability

If safety switches are installed on each module, then safety during fires and maintenance is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvesafety during fires and maintenanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sensor, switch, and control logic are integrated directly into the solar module's existing structure, combining multiple safety functions into a single unified component rather than requiring separate add-on systems. This integration simplifies manufacturing while maintaining comprehensive safety coverage.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated sensor and switch system serves multiple functions: monitoring connection status, detecting island mode, activating safety disconnection, and providing fault protection. This multi-functionality reduces the need for separate components and simplifies the overall manufacturing process.

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

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

Enables safe de-energization of the photovoltaic system by interrupting the DC line and resuming operation when necessary, reducing the risk of electric shocks and maintaining efficiency with minimal impact on energy supply.

Implementation Method 1

a plurality of solar cell strands (4) connected in series between the two connection terminals (9a, 9b)

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP2754183B1Solar module, photovoltaic system and method for operating such a system
Publication Date: 2017.06.28 SMA SOLAR TECH AG
  • EP2754183B1 patent drawingFigure 1~2
  • EP2754183B1 patent drawingFigure 3

AI summary

The invention relates to a solar module (3) that has a plurality of solar cells (4) connected to an output terminal (9a; 9b) and is part of a photovoltaic system (1) comprising a switchable connection (13) to an external load (11), wherein the solar module comprises an integrated switch (15a; 15b) arranged and designed to switch the output terminal from a high-impedance or de-energized resting state to a low-impedance or energized operating state, a sensor (19a) for determining a parameter characterizing the state of the connection between the photovoltaic system and the external load, and a switch controller (17), the input side of which is connected to the sensor, said switch controller being designed to periodically sample the sensor output and to actuate the switch or switches to switch the output terminal into the operating state in response to the detection of a connected state of the photovoltaic system. The invention further relates to a photovoltaic system with a plurality of such solar modules and to a method for operating such a system.