Solar String Shutdown Layout With Master-Slave Shut-Off Control
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Solution Overview
Problem
The high installation cost of shut-off devices in solar power generation systems and the need for improved stability during emergencies, such as fires, where rapid shutdown is mandated by National Electrical Code (NEC), necessitate a cost-effective and reliable solution.
Innovation Solution
A solar power generation system with a master-slave configuration of shut-off devices, where the first shut-off device cuts off connections between solar cell module groups in response to a control signal and outputs a second control signal via a communication system different from power line communication, simplifying the second shut-off device's configuration and reducing installation costs, while ensuring each group has an open-circuit voltage of 165 V or less for enhanced safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shut-off device is installed for each solar cell module to improve firefighter safety, then the safety of firefighters is improved, but the installation cost of shut-off devices increases
Solution Approach 1:
The patent merges the control functions of multiple shut-off devices into a single master shut-off device that controls multiple slave shut-off devices. This consolidation reduces the number of independent control units needed, thereby lowering installation costs while maintaining the safety function of rapidly shutting off power to multiple solar cell modules during emergencies
Solution Approach 2:
The patent segments the solar cell modules into multiple groups, with each group controlled by a slave shut-off device that is in turn controlled by a master shut-off device. This segmentation allows the system to maintain comprehensive safety coverage across all modules while using fewer expensive master control units, reducing overall installation cost
2Device complexity
If power line communication is used for communication between shut-off devices, then the communication system is simple, but the signal is affected by noise reducing communication stability
Solution Approach 1:
The patent introduces an intermediary communication system that translates control signals from the master shut-off device to slave shut-off devices through a different communication protocol or medium. This intermediary layer isolates the control system from electrical noise in the power lines, ensuring stable and reliable communication while maintaining system simplicity
Data Source
AI summary
A solar power generation system includes a string, an inverter a first shut-off device, and a second shut-off device. The string includes a plurality of solar cell module groups connected in series with each other. The first shut-off device connected to a first electric path connecting between the plurality of solar cell module groups. The second shut-off device connected to a second electric path connecting between the plurality of solar cell module groups. The first shut-off device cuts off a connection between the plurality of solar cell module groups connected to the first electric path in response to a first control signal from the inverter. The second shut-off device cuts off a connection between the solar cell module groups connected to the second electric path in response to a second control signal output from the first shut-off device by a communication system different from power line communication.