A single-phase photovoltaic grid-connected micro-inverter

Abstract

The invention discloses a single-phase photovoltaic grid-connected micro-inverter, which includes a photovoltaic module, a decoupling circuit is connected to the photovoltaic module, and a flyback inverter is connected to the output end of the decoupling circuit. A rear-stage full-bridge circuit is connected to the shock inverter, and an output end of the latter-stage full-bridge circuit is connected to a city power supply network. The beneficial effects of the present invention are: each photovoltaic module can be operated at the maximum power point, and the ability to resist partial shadow is strong; each flyback inverter is integrated with a single photovoltaic module, plug and play, and easy to install , the system is easy to expand; the flyback inverter occupies a small space, and the distributed installation is easy to configure, and can be installed in different directions and angles, which can make full use of the space; the failure of a single photovoltaic module will not affect the performance of the entire system. High redundancy and high reliability.

Description

Technical field [0001] The invention relates to a single-phase photovoltaic grid-connected micro inverter. Background technique [0002] At present, the construction mode of photovoltaic power plants in my country is no longer blindly seeking big ones, and the construction focus is gradually shifting from the centralized construction of megawatt-level demonstration power stations to small distributed power stations near the user side. In order to encourage the construction of distributed power stations, the National Energy Administration document (Guoneng Xinneng [2015] No. 73) stipulates that “there is no restriction on the construction scale of rooftop distributed photovoltaic power generation projects and all self-generated ground distributed photovoltaic power generation projects. The competent energy department accepts project filings at any time, and grid companies go through the grid connection procedures in a timely manner. The project will be included in the scope of sub...

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Problems solved by technology

[0009] Three-port decoupling method, the decoupling circuit is isolated from the photovoltaic module, the large voltage ripple on the decoupling capacitor will not affect the output characteristics of the photovoltaic module, and the capacitor voltage and voltage ripple are greatly improved by using the transformer ratio. The capacitor is smaller, but the voltage stress of the switching tube in the circuit is further increased, which will cause an increase in loss, and considering the isolation factor, the control of the secondary switching tube will be more complicated

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