Centralized-type photovoltaic power generation system capable of achieving distributed MPPT

Abstract

The invention discloses a centralized-type photovoltaic power generation system capable of achieving distributed MPPT, and the system comprises photovoltaic modules, photovoltaic optimizers, a voltage compensator, and a grid connected inverter. The output end of each photovoltaic module in the system is connected with one Buck type photovoltaic optimizer, so as to achieve the tracking of the maximum power of each photovoltaic module. The output ends of the photovoltaic optimizers are connected in series to form strings. Each string is connected with one isolated-type DC / DC converter, i.e., the voltage compensator, wherein the input end is connected with a DC bus, and the output end is connected to the string in a series manner. The plurality of strings are connected in parallel to form a photovoltaic array, and are connected with the grid connected inverter for grid connected power generation. The photovoltaic optimizers, the voltage compensator and the grid connected inverter communicate with each other in a mode of power signal recombination modulation communication. The system enables the power of the photovoltaic array to be maximum, and solves a problem of module-level mismatching and string-level mismatching. The proposed communication does not need additional wires and communication modules, so the communication cost is low, and the maintenance is simple.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation, and in particular relates to a centralized photovoltaic power generation system capable of realizing distributed MPPT. Background technique [0002] Photovoltaic power generation has the characteristics of clean, renewable, mature technology, and convenient installation, and has become one of the most promising renewable energy power generation methods. As of September 2015, China's cumulative photovoltaic power generation capacity has reached 37.95GW, including 31.7GW of photovoltaic power plants and 6.25GW of distributed photovoltaic power plants; most of the currently installed photovoltaic power plants are traditional centralized photovoltaic power generation systems. [0003] Large and medium-sized photovoltaic power generation systems usually adopt centralized grid-connected power generation, and its typical structure is as follows: figure 1 shown. A certain number o...

AI Technical Summary

Problems solved by technology

Although this method avoids the wiring problem of wired communication, the installation method of the antenna and the network debugging of wireless communication are more complicated, which reduces the reliability of the system

In addition, the wireless communication circuit also increases the cost of the system

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