Photovoltaic String IV Curve Scanning via Converter Power Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for IV curve scanning in photovoltaic string systems are inefficient and prone to errors due to manual measurement and batch scanning, which can be affected by weather conditions and result in delayed detection of faults, leading to reduced power generation capability.
Innovation Solution
A method involving a converter that controls the output voltage of photovoltaic strings to perform simultaneous IV curve scanning by dividing strings into groups with opposite initial scan directions and power change trends, ensuring precise and timely detection without time intervals, thereby compensating for weather impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurement method is used for IV curve scanning, then measurement precision can be maintained, but productivity is severely reduced due to time-consuming process
Solution Approach 1:
The patent replaces manual mechanical measurement operations with automated electronic control systems. The converter automatically performs IV curve scanning by controlling voltage changes and measuring current responses, eliminating the need for manual instrument operation while maintaining measurement accuracy through digital signal processing.
Solution Approach 2:
The system enables self-service measurement where the photovoltaic string itself provides the measurement signal. By utilizing the string's own electrical characteristics during normal operation, the system performs self-diagnosis without requiring external measurement devices or manual intervention, thus improving both efficiency and accuracy.
2Device complexity
If batch scanning is performed on photovoltaic strings, then device complexity is reduced, but measurement precision deteriorates due to weather condition variations during scanning intervals
Solution Approach 1:
The patent implements continuous scanning operation where the converter continuously monitors and scans the IV characteristics of photovoltaic strings without interruption. This eliminates the time gaps between batch scans, ensuring that measurements are taken under consistent weather conditions and eliminating the need for complex batch scheduling systems.
3Productivity
If simultaneous scanning of all photovoltaic strings is implemented, then productivity is improved, but device complexity increases due to need for coordinated control
Solution Approach 1:
The converter is designed with multi-functionality, serving both as a power conversion device and as an IV curve scanning instrument. This universal design allows simultaneous scanning of multiple photovoltaic strings without requiring separate dedicated measurement equipment, thus improving productivity while avoiding the complexity of coordinated multi-device control systems.
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 efficient and precise IV curve scanning of all photovoltaic strings simultaneously, reducing power generation losses by detecting faults early and maintaining stable output power, independent of weather conditions.
Implementation Method 1
A photovoltaic string 100 converts solar energy into electric energy by using a photovoltaic effect
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention discloses a current-voltage curve scanning method for a photovoltaic string, a converter, and a system, including: obtaining output powers at initial scanning points of photovoltaic strings in a first group and a second group; controlling the output powers at the initial scan points of the photovoltaic strings in the first group to sequentially decrease, and controlling the output powers at the initial scan points of the photovoltaic strings in the second group to sequentially increase, where an initial scanning direction of each photovoltaic string in the first group is a direction in which an output voltage changes as an output power decreases and an initial scanning direction of each photovoltaic string in the second group is a direction in which an output voltage changes as an output power increases; performing scanning in the initial scanning direction starting from output voltages corresponding to the output powers at the initial scan points of the first group; and performing scanning in the initial scanning direction starting from output voltages corresponding to the output powers at the initial scan points of the second group; and output powers of the first group and the second group are kept to compensate each other during IV curve scanning. Therefore, scanning is simultaneously performed on all photovoltaic strings, instead of being performed in batches.