A single-phase photovoltaic grid-connected micro-inverter

Abstract

The invention discloses a single-phase photovoltaic grid-connected micro-inverter comprising a photovoltaic assembly which is connected to a decoupling circuit. An output terminal of the decoupling circuit is connected to a flyback inverter. The flyback inverter is connected to a rear-stage full-bridge circuit. An output terminal of the rear-stage full-bridge circuit is connected to a municipal power-supply network. The beneficial effects of the present invention are that each photovoltaic assembly works at a maximum power point; the anti partial-shading capability is strong; each flyback inverter is integrated with a single photovoltaic assembly; the single-phase photovoltaic grid-connected micro-inverter can be used once plugged; the installation is convenient; the system expansion is convenient and simple; the space occupied by the flyback inverter is small; the single-phase photovoltaic grid-connected micro-inverter is installed in a distributed mode so as to provide convenience for configuration; and the single-phase photovoltaic grid-connected micro-inverter can be installed in different directions at different angles so as to fully utilize space. The failure of a single photovoltaic assembly will not influence the performance of the whole system. The redundancy of the system is high and the reliability is high.

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 my country's photovoltaic power plants is no longer blindly pursuing large scale, and the construction focus is gradually shifting from the centralized construction of megawatt-level demonstration power plants to small distributed power plants close to 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 distributed photovoltaic power generation projects on the roof and all self-contained ground distributed photovoltaic power generation projects. Energy authorities accept project filings at any time, grid companies handle grid connection procedures in a timely manner, and projects will be included in the scope of subsidies after ...

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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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