PV Module Electronic Circuit for Safe Series Connection
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Solution Overview
Problem
Existing vehicle-integrated photovoltaic systems face challenges in safely connecting PV modules in series due to high voltages exceeding safety limits, especially during accidents or disconnection events, without complex communication channels or additional components.
Innovation Solution
An electronic circuit that reverses current flow direction to enable decentralized decision-making for connecting or disconnecting PV modules from the string, using semiconductor switches and body diodes to manage voltage safely, without a separate communication channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If series connection of PV modules is implemented to enable high voltage operation, then power output is improved, but safety risk increases due to high voltages during accidents or disconnection events
Solution Approach 1:
The PV string is divided into multiple independent PV modules, each with its own electronic circuit and disconnection device. This segmentation allows individual modules to be disconnected from the series connection when safety risks are detected, while other modules can continue operating. The current path is split into multiple independent paths, each controllable by its own disconnection device.
Solution Approach 2:
The disconnection devices are pre-positioned in each PV module's electronic circuit, ready to interrupt the current path immediately when safety risks are detected. The control devices are pre-programmed with safety logic to detect accident conditions or disconnection events and trigger the disconnection devices before dangerous high voltages can cause harm.
2Reliability
If decentralized electronic circuits are used in each PV module to enable autonomous connection decisions, then reliability is improved, but device complexity increases
Solution Approach 1:
The electronic circuit in each PV module is designed to perform multiple functions: it monitors current flow direction, detects safety conditions, controls the disconnection device, and manages module connection to the string. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall device complexity while maintaining decentralized reliability.
Solution Approach 2:
Each PV module's electronic circuit autonomously monitors its own current flow and safety conditions, and independently controls its own disconnection device without requiring constant external control signals. The module serves itself by detecting when it needs to disconnect and executing the disconnection autonomously, which improves reliability by reducing dependency on external control systems.
3Object-affected harmful factors
If communication channels are added between central controller and PV modules for safe connection control, then safety is improved, but material cost and system complexity increase
Solution Approach 1:
The patent replaces the need for electrical communication channels with a direct electrical connection that serves dual purposes: power transmission and control signaling. The current flow itself carries the control information, eliminating the need for separate communication wires or protocols between the central controller and PV modules.
Solution Approach 2:
The control function is merged with the power transmission function. The same electrical conductors that carry power from PV modules to the central controller also carry the control signals needed for safe operation. This merging eliminates the need for separate communication infrastructure, reducing material costs and system complexity.
4Object-affected harmful factors
If service disconnect box is used to disconnect PV circuit during accidents, then safety is improved, but high voltage remains in PV circuit during disconnection
Solution Approach 1:
Instead of a single central disconnect point, the patent implements multiple distributed disconnection devices, one in each PV module. This segmentation ensures that when a disconnect event occurs, the voltage is isolated at the module level, preventing high voltage from remaining in the PV circuit. Each module can be independently disconnected, ensuring complete voltage isolation.
Solution Approach 2:
The disconnection devices are positioned within each PV module's electronic circuit, allowing the disconnect action to occur at the source of the high voltage. This preliminary disconnection at the module level prevents high voltage from propagating through the circuit, ensuring that the PV circuit is fully de-energized during accident conditions.
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
Enables safe series connection of PV modules with high voltages during normal operation, reducing voltage when necessary, and simplifies the connection process with low material and complexity, ensuring safety and reliability.
Implementation Method 1
The isolation device is configured to conduct the current flow via the body diode along the second current flow direction in the first state of the isolation device
Data Source
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AI summary
The invention relates to an electronic circuit for a PV module comprising PV connections for coupling to a PV module and string connections for coupling to a PV string. A current path runs between the PV connections and the string connections, said current path being designed to conduct an electric current generated in the PV module to the PV string in a first current flow direction. The electronic circuit comprises a separating device which is arranged between a first connection of the PV connections and a second connection of the string connections and which is designed to interrupt the current path along the first current flow direction in a first state and to close the current path along the first current flow direction in a second state. The electronic circuit comprises a controller which is designed to obtain current flow information on a current flow in at least one sub-section of the current path along a second current flow direction opposite the first current flow direction and to control the separating device from the first state into the second state on the basis of the current flow information.