PV Rapid Shutdown Circuit Using Power Line Communication
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Solution Overview
Problem
Current rapid shutdown devices for photovoltaic modules are limited by the need for multiple devices per string, especially with the progression from array-level to module-level shutdown requirements, and they often require additional wiring, which complicates installation and compatibility with various inverter types.
Innovation Solution
A rapid shutdown system that includes a high voltage switch and a gate drive circuit, integrated with a communication circuit and power supply, allowing for power line communication and enabling module-level shutdown with a single device capable of handling voltages up to 600V, and designed to fit within existing wireways, using non-conductive materials for the electronics housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple rapid shutdown devices are installed per string to meet module-level shutdown requirements, then safety and compliance are improved, but device complexity and installation difficulty increase
Solution Approach 1:
The patent combines multiple rapid shutdown device functions into a single integrated device that can handle module-level shutdown for entire strings. This consolidation reduces the number of devices needed while maintaining safety requirements, directly resolving the contradiction between safety compliance and device complexity.
Solution Approach 2:
The rapid shutdown device is designed with multi-functional capabilities including voltage switching, power line communication, and compatibility with various inverter types. This universality allows one device to perform multiple functions that previously required separate components, reducing overall system complexity while meeting safety standards.
2Reliability
If additional wiring is added for rapid shutdown devices, then electrical connection reliability is improved, but installation complexity and time increase
Solution Approach 1:
The device utilizes existing power lines for both power transmission and communication purposes. The power line communication capability allows the device to receive shutdown commands through the existing electrical infrastructure without requiring separate communication wiring, thereby maintaining reliability while reducing installation time and complexity.
3Device complexity
If a single rapid shutdown device handles entire strings at 600V, then device quantity is reduced, but voltage handling requirements and safety risks increase
Solution Approach 1:
The patent incorporates a non-conductive housing as an intermediary barrier between the high voltage components and the environment. This housing provides electrical insulation and safety protection, allowing the device to handle 600V strings safely while maintaining a reduced device quantity. The non-conductive material acts as a mediator that enables high voltage operation without increasing safety risks.
Data Source
AI summary
A rapid shutdown device for rapidly de-energizing a photovoltaic module system is disclosed. The rapid shutdown device includes power lines connected to a photovoltaic string of modules on a roof of a structure. A high voltage switch on a first power line is disconnected when the high voltage switch is open. The rapid shutdown device includes a gate drive circuit that receives an electronic photovoltaic string status signal associated with an operating status of the photovoltaic string. The gate drive circuit may determine that the operating status indicates the presence of a hazard based on the electronic photovoltaic string status signal. Based on presence of the hazard, the rapid shutdown device generates a high voltage switch command signal to cause the high voltage switch to open to disconnect the photovoltaic string from an electrical connection to a grid power supply, thereby enhancing protection of the string and safety for responders.