Module-Level PV Power Control for Safe DC Voltage Reduction
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Solution Overview
Problem
Photovoltaic power generation systems face safety hazards due to high direct current voltages, which can lead to fires and pose risks to maintenance personnel. Additionally, the existing systems lack effective mechanisms to reduce voltage levels during maintenance or faults, compromising long-term stability and safety.
Innovation Solution
A power conversion device with a direct current conversion unit, signal processing unit, and controller is introduced. This device communicates with a next-level power conversion device using power line communication and switches between three working modes: normal, safe, and shutdown. The controller adjusts the output voltage based on received periodic communication signals, ensuring safety and maximizing power generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photovoltaic modules are connected in series to obtain large power generation power, then power generation efficiency is improved, but direct current voltage becomes excessively high creating safety hazards
Solution Approach 1:
The patent divides the photovoltaic power generation system into multiple independent power conversion devices, each handling a portion of the total power. This segmentation allows the system to achieve high power generation capacity without requiring excessively high voltage from individual modules, thereby reducing safety hazards while maintaining productivity.
Solution Approach 2:
The patent employs multiple power conversion devices operating in parallel, each converting DC to AC at standard voltage levels. By changing the system architecture from series connection (high voltage) to parallel connection of multiple units (standard voltage), the system achieves high power generation without excessive voltage, resolving the safety hazard.
2Device complexity
If high direct current voltage is used to reduce system complexity, then fewer components are needed, but maintenance personnel face safety risks and equipment damage
Solution Approach 1:
The system is divided into multiple independent power conversion devices that can be maintained separately. Each device operates at safe voltage levels, allowing maintenance personnel to work on individual units without exposure to high voltage risks, while the overall system remains relatively simple in structure.
Solution Approach 2:
The patent introduces communication signals and control mechanisms as intermediaries between power conversion devices. These intermediaries enable coordinated operation of multiple standard-voltage devices, achieving system-level functionality without requiring high voltage connections, thus protecting maintenance personnel while maintaining system simplicity.
3Productivity
If photovoltaic modules are installed close to power consumption users, then power generation efficiency is improved, but safety hazards cannot be ignored
Solution Approach 1:
The patent distributes multiple power conversion devices across different locations near power consumption users. Each device processes a portion of the power at safe voltage levels, maintaining high overall power generation efficiency while eliminating the safety hazards associated with集中 high-voltage installations.
Solution Approach 2:
By changing the voltage parameter from high DC voltage to standard AC voltage through multiple conversion devices, the system enables safe installation close to users while maintaining high power generation efficiency. The parameter transformation from high voltage to standard voltage resolves the safety hazard.
4Productivity
If excessive high direct current voltage is used, then power generation capacity is increased, but long-term stable operation is compromised
Solution Approach 1:
The patent divides the power generation capacity into multiple independent conversion devices, each operating within safe voltage parameters. This segmentation ensures that no single device experiences excessive voltage stress, thereby maintaining high overall power generation capacity while ensuring long-term stable operation through reduced wear and failure risk.
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 solution effectively reduces the output voltage to a safe level during maintenance or faults, enhancing personal safety and system security. It also ensures maximum power generation and efficient communication using existing power lines, reducing costs and improving system reliability.
Implementation Method 1
The signal processing unit is located on an output side of the power conversion device, and the signal processing unit is configured to receive a periodic communication signal sent by the next-level power conversion device
Data Source
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AI summary
A power device, a power device control method, and a photovoltaic power generation system are provided. An input end of a module-level power electronics device is connected to a photovoltaic module, and output ends of the module-level power electronics device are connected in series and then connected to an inverter. The component-level power electronics device includes a direct current conversion unit, a signal processing unit, and a controller. The direct current conversion unit is configured to implement direct current-direct current power conversion. The signal processing unit is configured to receive a periodic communication signal sent by the inverter. The controller is configured to control the component-level power electronics device to switch between a shutdown mode, a normal working mode, and a safe working mode, which specifically includes: when the component-level power electronics device fails to receive the periodic communication signal, maintaining or switching to the shutdown mode; when the periodic communication signal received by the component-level power electronics device includes a heartbeat frame and does not include a voltage adjustment instruction, switching to the normal working mode; or when the periodic communication signal received by the component-level electric power electronics device includes the heartbeat frame and also includes the voltage adjustment instruction, switching to the safe working mode. The three working modes provided in this application can ensure safety of both a device and a person, have a fast response speed, and are easy to implement.