Solar Module Decoupling Circuit for Fire-Safe PV Shutdown
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Solution Overview
Problem
Photovoltaic systems installed on roofs pose a fire hazard as they cannot be turned off, increasing the risk for firefighters, and existing solutions to mitigate this hazard are costly and may compromise system reliability.
Innovation Solution
A solar system configuration that includes a device to electrically decouple solar modules from the system using a low-cost, low-power transformer and thermal switches or power transistors, which provide a closed circuit when an AC signal is present and an open circuit when it is not, allowing for safe disconnection of modules during emergencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solar modules are permanently connected to the solar system, then system reliability and simplicity are maintained, but electrical hazard during fires increases
Solution Approach 1:
The patent introduces a decoupling device as an intermediary component between the solar module and the solar system. This device includes a transformer and switching mechanism that allows the module to be electrically disconnected from the system during emergencies while maintaining normal operation during regular use, thus reducing electrical hazard without permanently complicating the system
Solution Approach 2:
The patent implements a dynamic connection system where the electrical connection between the solar module and the solar system can change from connected to disconnected state. The decoupling device uses switches or circuit breakers that can open the circuit during fire emergencies, transforming the static permanent connection into a dynamic controllable connection, thereby reducing electrical hazard while maintaining operational flexibility
2Object-affected harmful factors
If decoupling devices are added to solar modules, then electrical hazard during fires is reduced, but system cost increases
Solution Approach 1:
The patent employs relatively simple and inexpensive decoupling devices that can be integrated into each solar module. The design uses basic electrical components such as transformers, switches, and circuit breakers that are cost-effective and do not require complex or expensive specialized equipment, thereby reducing electrical hazard while minimizing cost increase
Solution Approach 2:
The patent applies segmentation by implementing decoupling devices at the individual module level rather than requiring a complex centralized system. This allows each module to be independently controlled and disconnected if needed, using simple, inexpensive components locally, thereby reducing electrical hazard while keeping overall system cost low through modular simplicity
3Object-affected harmful factors
If decoupling devices are added to solar modules, then electrical hazard during fires is reduced, but system reliability may be compromised
Solution Approach 1:
The patent implements preliminary action by pre-configuring the decoupling device in each solar module during manufacturing. The device includes pre-set switches and protection mechanisms that are ready to activate automatically or manually during fire emergencies, ensuring that the module can be quickly disconnected without compromising the reliability of the overall solar system during normal operation
Solution Approach 2:
The patent extracts the decoupling function from the main solar system architecture and integrates it as a separate, independent device within each module. This extraction allows the decoupling mechanism to operate independently without interfering with the core solar system's reliability, while still providing the necessary electrical disconnection capability during emergencies
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 effectively reduces electrical hazards during fires without significant cost or reliability impact on the PV system, ensuring safe firefighting conditions while maintaining system functionality.
Implementation Method 1
low-cost, low-power transformer
Implementation Method 2
thermal switches
Data Source
AI summary
Devices and methods for electrically decoupling a solar module from a solar system are described. In one embodiment, a solar system includes a string of a plurality of solar modules coupled with an inverter through a DC power line. An AC input is coupled with the DC power line. A device is also included and is configured to provide a closed circuit for one of the plurality of solar modules if an AC signal voltage from the AC input is present on the DC power line, and is configured to provide an open circuit for the one of the plurality of solar modules if no AC signal voltage from the AC input is present on the DC power line.