PV Shutdown Controller Power Routing for Inverter Voltage Stability
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Solution Overview
Problem
In photovoltaic systems, shutdown devices connected to photovoltaic modules continue to output high-voltage direct current power after the inverter is switched off, posing hazards and instability due to voltage fluctuations when a power supply photovoltaic module is shaded and under-voltage protection threshold is reached, causing the shutdown controller to malfunction.
Innovation Solution
Implementing a shutdown controller that switches off the shutdown device connected to the power supply photovoltaic module when its input voltage reaches a preset protection voltage higher than the under-voltage threshold, ensuring the bypass diode bypasses the power supply module to supply power only to the shutdown controller, maintaining stable operation of other modules and the inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shutdown controller is powered by a photovoltaic module, then the shutdown controller can operate autonomously, but when the photovoltaic module is shaded and voltage drops to the under-voltage protection threshold, the shutdown controller is powered off, causing all connected photovoltaic modules to be switched off and resulting in large voltage fluctuations that destabilize the inverter operation
Solution Approach 1:
The patent segments the power supply function by introducing a dedicated power supply photovoltaic module that only supplies power to the shutdown controller, separated from the main photovoltaic modules that supply power to the inverter. This segmentation ensures that shading of main modules does not affect controller operation, and controller power issues do not affect inverter operation.
Solution Approach 2:
The patent introduces a dedicated power supply photovoltaic module as an intermediary component between the main photovoltaic modules and the shutdown controller. This intermediary ensures stable power supply to the controller independent of the main modules' shading conditions, preventing cascading failures.
2Reliability
If the shutdown device connected to a power supply photovoltaic module is switched off to ensure controller operation, then the controller remains powered, but the module's voltage output is isolated from the inverter, requiring careful management to maintain overall system power output
Solution Approach 1:
The patent segments the electrical circuit by introducing a switch that can isolate the power supply photovoltaic module from the inverter while maintaining its connection to the shutdown controller. This allows independent control of power routing to different components.
Solution Approach 2:
The patent implements dynamic control of the switch connecting the power supply photovoltaic module to the inverter, adjusting the connection state based on the module's voltage output and shading conditions to optimize both controller power supply and inverter power input.
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
Prevents voltage fluctuations at the inverter by ensuring the shutdown controller operates properly, allowing other modules to continue supplying voltage to the inverter, thereby stabilizing the photovoltaic system operation.
Implementation Method 1
a bypass diode is connected in parallel between a positive output terminal and a negative output terminal of each of the photovoltaic modules
Data Source
AI summary
A shutdown device control method, system and apparatus, and a shutdown controller. If the shutdown controller detects that an input voltage of the shutdown controller is reduced, when the input voltage of the shutdown controller is reduced to a preset protection voltage but has not been reduced to an undervoltage protection threshold voltage, the shutdown controller controls the shutdown of a shutdown device connected to a power supply photovoltaic assembly that supplies power to the shutdown controller, so that a bypass diode connected to the power supply photovoltaic assembly bypasses the power supply photovoltaic assembly, so that the power supply photovoltaic assembly only supplies power to the shutdown controller. After the shutdown device connected to the power supply photovoltaic assembly is shut down, the power supply photovoltaic assembly cannot output any voltage to a photovoltaic inverter apparatus, but voltages outputted by the power supply photovoltaic assembly are all supplied to the shutdown controller to ensure the normal operation of the shutdown controller, thereby ensuring that photovoltaic assemblies, other than the power supply photovoltaic assembly, among photovoltaic assemblies corresponding to the shutdown controller still output voltages to the photovoltaic inverter apparatus, and avoiding large fluctuations in the voltage of the photovoltaic inverter apparatus.