A micro photovoltaic grid-connected inverter and its grid-connected control method

Abstract

The invention discloses a micro photovoltaic grid-connected inverter and a grid-connected control method of the micro photovoltaic grid-connected inverter. The inverter comprises an active-clamp interleaved flyback circuit, a full-bridge circuit, an EMI circuit, a detection circuit and a main control chip, wherein direct-current voltage output by an external solar panel is input to the interleaved flyback circuit, the interleaved flyback circuit comprises two flyback circuits and two active-clamp circuits, the two flyback circuits alternately work with a phase difference of 180 degrees, and the output end of the interleaved flyback circuit is connected with the input end of the full-bridge circuit; the full-bridge circuit comprises a gate drive transformer, an upper bridge arm and a lower bridge arm, the upper bridge arm and the lower bridge arm are driven by the gate drive transformer, and the full-bridge circuit is connected with a power network through the EMI circuit; the main control chip is in data communication with the interleaved flyback circuit and the full-bridge circuit through the detection circuit. The method comprises a deadbeat grid-connected algorithm based on current control, an MPPT algorithm based on current disturbance, and the like. The micro photovoltaic grid-connected inverter disclosed by the invention has the advantages of low grid-connected harmonic rate, high efficiency of maximum power tracking and strong anti-shadow ability.

Description

technical field [0001] The invention relates to the research field of inverters, in particular to a miniature photovoltaic grid-connected inverter and a grid-connected control method thereof. Background technique [0002] From the perspective of total consumption, my country is a big energy country. However, due to the increasingly serious environmental protection problems and the depletion of traditional energy sources, photovoltaic power generation has attracted more and more attention due to its unique advantages. [0003] Photovoltaic power generation is mainly divided into centralized type, string type and micro inverter. Centralized and string inverters have large output power, but cannot track the maximum power of each photovoltaic panel, and have poor anti-shading ability. The traditional inverter control is only tracking according to the maximum power that the photovoltaic panel can achieve, while ignoring the maximum power that the inverter itself can work. If th...

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Problems solved by technology

If the photovoltaic panel works at the maximum power that can be achieved, it may exceed the maximum power of the inverter itself, which will eventually lead to damage to the inverter

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