Outdoor power generation characteristic and attenuation condition testing system for photovoltaic assembly

Abstract

The invention provides an outdoor power generation characteristic and attenuation condition testing system for a photovoltaic assembly, and the system comprises a photovoltaic module, a photovoltaic module selector, a filter, a converter, a plurality of groups of serial-type inverters, a current-voltage characteristic curve tester, a radiation intensity tester, an environment parameter sensor, a data collector, a thermocouple, a thermocouple selector, and a processing system. The testing system can accurately obtain the power generation characteristic and attenuation conditions of various types of photovoltaic assemblies in different climate environments through the testing and comparison of AC / DC electrical parameters and environment parameters of various types of photovoltaic assemblies or photovoltaic assembly strings under the outdoor work condition. The system can test all parameters of the photovoltaic assemblies or photovoltaic assembly strings under the true grid-connected condition without affecting the normal work and power generation, is precise and reliable in testing result, and can test the power generation characteristic, reliability and attenuation conditions of the photovoltaic assemblies or photovoltaic assembly strings.

Description

technical field [0001] The invention belongs to the field of photovoltaic testing, in particular to a testing system for outdoor power generation characteristics and attenuation conditions of photovoltaic modules. Background technique [0002] With the depletion of fossil energy, new energy has attracted worldwide attention. Solar energy is an inexhaustible clean and renewable energy, among which photovoltaic power generation technology, as an important direction of solar energy utilization, will play an important role in the future energy industry. The great development of the photovoltaic power generation industry has become unstoppable, which also puts forward higher requirements for the evaluation of the power generation and attenuation characteristics of photovoltaic systems and modules. In the present invention, each basic unit of power generation is called a solar cell, corresponding to the "Solar cell" in English, and a power generation unit composed of several sing...

AI Technical Summary

Problems solved by technology

The outdoor exposure experiment only scans the I-V curve of photovoltaic modules intermittently. Although the data is relatively accurate, it lacks real grid-connected conditions, and it is not a continuous power output, and the power attenuation of the module with the working time under normal working conditions The situation is also very different; to measure the AC and DC output of photovoltaic modules under grid-connected conditions, centralized inverters, string inverters or micro-inverters are generally used. The experimental principle is as follows: figure 1 , mainly measure the DC data of the first port and the AC data of the second port, and the DC data is affected by the tracking accuracy of the inverter MPPT, and the AC data is affected by the fluctuation of the power grid and the dynamic efficiency of the inverter itself. The measured data has large errors and is difficult to fix

In Chinese patent 201010046547.7 "Photovoltaic grid-connected inverter with photovoltaic array IV test function and test method", a filter capacitor is connected in parallel between the photovoltaic array and the inverter, and the photovoltaic array and the capacitor must be disconnected during the array test. , after the capacitor is discharged, the inverter is disconnected from the grid, the photovoltaic array recharges the capacitor, and the voltage and current change curve during the charging process is tested to obtain the I-V characteristics of the photovoltaic array. During the entire test process, the switch is closed many times, and After the inverter is disconnected from the power grid, it takes too long to reconnect and resume work. Sometimes the inverter cannot even start normally, which seriously affects the collection of experimental data. In addition, the test system has complex control circuits and insufficient measurement accuracy. Generally, it is only suitable for photovoltaic array failures. Detection; Chinese patent 201110068401.7 "Method for Establishing Test Diagnosis and Prediction Database of Photovoltaic Power Station Based on Demonstration Demonstration" uses a variety of photovoltaic modules and inverters for testing, and records the AC and DC data of photovoltaic modules. The data is too dependent on the influence of factors such as MPPT efficiency and inverter inverter efficiency, especially the dynamic changes are difficult to measure, and cannot objectively reflect the actual power generation capacity of photovoltaic modules. Generally, it is only suitable for testing the efficiency of photovoltaic inverters

[0004] Looking at the existing research results at home and abroad, there are still many problems in the testing methods of photovoltaic modules: First, the understanding of the characteristics of photovoltaic power generation is not comprehensive, the system design and construction are unreasonable, and the power generation status and attenuation characteristics of photovoltaic modules are correctly and accurately estimated Second, the electrical parameters of various photovoltaic modules are not the same, or even have large differences. Due to the limitations of system design and testing equipment, the testing methods of various components are different, and the data compatibility is poor; third, The manufacturing technology of batteries is constantly updated, and the structure of raw materials and modules is also constantly changing, but the corresponding research on reliability and attenuation characteristics is relatively backward. A time-sensitive system that can correctly predict the attenuation of photovoltaic modules needs to be established urgently

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