Solar String Shutoff Circuit for Dual-Path Emergency Isolation
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Solution Overview
Problem
Conventional solar power generation systems lack reliable safety measures during emergencies, as they only cut off one electric path, leaving potential risks for firefighters and others.
Innovation Solution
A solar power generation system with dual shutoff devices and a bypass mechanism that can simultaneously or independently cut off both electric paths connecting the string and inverter, and optionally include a bypass device to reroute power, ensuring comprehensive electrical cutoff and improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shutoff device cuts off only one electric path, then the device complexity is reduced, but the safety and reliability are insufficient
Solution Approach 1:
The shutoff device is segmented into two independent switching units (first switching unit and second switching unit), each responsible for cutting off a different electric path. This segmentation allows the system to maintain lower complexity at the component level while achieving higher reliability through redundant coverage of both electric paths connecting the string and inverter.
2Reliability
If both electric paths are cut off simultaneously, then the safety is improved, but the device complexity increases due to dual switching units
Solution Approach 1:
The first switching unit and second switching unit are merged into a single integrated shutoff device structure, sharing common control circuitry and housing. This merging approach reduces overall device complexity while maintaining the dual-path cutoff capability, as the two switching units operate under unified control rather than as completely separate devices.
3Reliability
If a single shutoff device is used, then the device complexity is low, but it cannot provide comprehensive electrical cutoff of both paths
Solution Approach 1:
The solution transitions from a single-dimension approach (one switching unit per electric path) to a two-dimension approach by adding switching units in both the anode side electric path and the cathode side electric path. This dimensional expansion ensures comprehensive cutoff capability across multiple electric paths while maintaining a coordinated device structure.
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
The system effectively enhances safety by ensuring reliable electrical cutoff of both paths, reducing the risk of electrical hazards during emergencies and allowing for efficient power rerouting in case of module abnormalities.
Implementation Method 1
A string 2 includes a plurality of solar cell modules 6 connected in series
Implementation Method 2
an inverter 3 connected to the string 2 and configured to convert DC power output from the string 2 to AC power
Data Source
AI summary
A solar power generation system includes a string, an inverter, a first shutoff device, and a second shutoff device. The string includes a plurality of solar cell modules connected in series. The first shutoff device includes a first switching unit and a second switching unit, and turns OFF the switching units, in response to a first control signal from the inverter. The first switching unit is connected to an anode side terminal of the string and an anode side terminal of the inverter. The second switching unit is connected to a cathode side terminal of the string and a cathode side terminal of the inverter. The second shutoff device cuts off a solar cell module group including one or more among the plurality of solar cell modules and either another solar cell module or the inverter in response to a second control signal from the first shutoff device.