Solar Module Shut-Off Architecture for Emergency Voltage Isolation
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Solution Overview
Problem
Photovoltaic systems pose a safety risk due to lethal voltage potentials, inhibiting the installation of more solar panels in series and posing dangers to first responders and maintenance personnel, especially in emergency situations where existing shut-off systems may be damaged.
Innovation Solution
A system of local management units (LMUs) controlled by a central controller allows for remote or local shut-down of solar modules, with communication protocols enabling self-adjustment and safety features to manage voltage and current, and a master management unit (MMU) for centralized control and configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solar panels are connected in series to reduce cost of combiner boxes or string inverters, then system cost efficiency is improved, but voltage potential becomes lethal and safety risk increases
Solution Approach 1:
The system divides the solar array into multiple independent strings, each with its own safety control capability. The central controller can individually manage each string's shutdown, segmenting the overall system to maintain cost efficiency through series connections while isolating safety risks to specific segments rather than the entire array.
2Object-affected harmful factors
If existing shut-off systems are used in emergency situations, then personnel safety is improved, but the shut-off system may be damaged or disabled by the emergency
Solution Approach 1:
The system performs preliminary actions by continuously monitoring voltage and current levels before emergencies occur. The central controller proactively identifies potential hazards and can initiate preventive shutdowns, acting before the emergency fully develops and potentially damages the shut-off system.
Solution Approach 2:
The system employs feedback mechanisms where the central controller continuously receives data from sensors monitoring voltage, current, and system status. This real-time feedback enables the controller to detect emergency conditions and activate shut-off protocols before the emergency compromises the shut-off system's integrity.
3Object-affected harmful factors
If a large guard band is applied to keep voltages below 600V or 1000V limits, then personnel safety is improved, but the number of solar panels that can be installed in series is reduced
Solution Approach 1:
The system dynamically adjusts operational parameters including voltage and current levels based on real-time conditions. The central controller can optimize the guard band application, allowing higher voltages when safe and reducing them when risks are detected, thereby maximizing installation capacity while maintaining personnel safety through adaptive rather than static voltage management.
Data Source
AI summary
Systems and methods for shut-down of a photovoltaic system. In one embodiment, a method implemented in a computer system includes: communicating, via a central controller, with a plurality of local management units (LMUs), each of the LMUs coupled to control a respective solar module; receiving, via the central controller, a shut-down signal from a user device (e.g., a hand-held device, a computer, or a wireless switch unit); and in response to receiving the shut-down signal, shutting down operation of the respective solar module for each of the LMUs.