Intelligent photovoltaic topological transformation power optimization system and control method thereof

Abstract

The invention discloses an intelligent photovoltaic topological transformation power optimization system and a control method. The system comprises a switch control module, a current acquisition module, a central processing module, a switch module, a plurality of photovoltaic string modules and a plurality of MPPT modules. The switch control module and the current acquisition module are both connected with the central processing module, and the switch module is connected with the switch control module; the two ends of the switch module are respectively connected with each photovoltaic string module and each MPPT module; the current acquisition module is used for acquiring the current magnitude of each photovoltaic string module and inputting the current magnitude into the central processing module; and the central processing module is used for controlling the switch of each switch module through the switch control module according to the current of each photovoltaic string module so as to adjust the connection mode between each photovoltaic string module and each MPPT module. The system and the method have the advantages of improving the conversion efficiency of the MPPT modules in cloudy and rainy days or under the condition of weak light, reducing the loss, improving the power generation efficiency and the like.

Description

technical field [0001] The invention mainly relates to the field of photovoltaic technology, and in particular to an intelligent photovoltaic topology conversion power optimization system and a control method thereof. Background technique [0002] With the vigorous development of the photovoltaic industry, the application scenarios of photovoltaic systems are becoming more and more extensive. How to improve the efficiency of photovoltaic systems and optimize the power output of photovoltaic systems, many solutions have been proposed for each link of the system. For example, in terms of photovoltaic combiner boxes, some manufacturers have proposed smart combiner boxes to monitor the current of strings in real time, cut off faulty strings in time, and improve system efficiency; in terms of photovoltaic modules, some people have proposed power optimization for single modules; in terms of design, The industry explores the layout of inverters and combiner boxes in photovoltaic ar...

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Problems solved by technology

[0003] For large-scale photovoltaic power plants on the ground, the number of photovoltaic modules generally reaches tens of thousands. Since the CN105227126A invention patent performs maximum power tracking for each module, the number of power optimizers is huge, and communication and centralized control between power optimizers will result in two The secondary system is huge, which increases the system cost. In addition, if there is a problem with the optimizer, it will easily lead to problems with the entire system.

The CN104660166A invention patent optimizes the power of each string. Similarly, the number of MPPTs increases significantly with the increase of the system scale. Under low light conditions, the output current of a single string is too small for MPPT to work, which will also lead to power generation loss.

CN104506132A invention patent only proposes to bypass the shading panels and disconnect the output of faulty panel strings to improve efficiency, but does not propose how to improve the conversion efficiency of the inverter under weak light conditions, thereby improving the system efficiency

[0004] The output power of photovoltaic modules is related to light and temperature. Generally, the output current of modules is greatly affected by light intensity. The higher the light intensity, the greater the output current; the output voltage of modules is greatly affected by temperature. The lower the conversion efficiency of the photovoltaic inverter is greatly affected by the input power, when the input power is lower than 10% of the rated power, the conversion efficiency of the inverter will be lower than 95%, which reduces the power generation efficiency of the entire photovoltaic system

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