Input and output common-ground boost-buck photovoltaic grid-connected inverter and control method thereof

Abstract

The invention discloses an input and output common-ground boost-buck photovoltaic grid-connected inverter and a control method thereof. The photovoltaic grid-connected inverter disclosed by the invention comprises five switch tubes, three diodes, two inductors and a capacitor. The input and output common-ground boost-buck photovoltaic grid-connected inverter has the beneficial effects that voltage at two ends of a ground parasitic capacitor of a photovoltaic cell panel is zero and remains unchanged; leakage current is effectively eliminated; input and output of the inverter are common-grounded and are beneficial to building of a three-phase system and the applications of the inverter can be further expanded; boosting and bucking can be achieved by a single stage of the inverter, the grid-connected voltage requirement can be achieved by a DC side only by low voltage and the application range of the inverter is expanded; a transformer does not exist in a circuit, the required active and passive devices are few and a system is high in efficiency, small in volume and light in weight; and an electrolytic capacitor does not exist in the circuit, the reliability of the circuit is improved and the service life of the circuit is prolonged.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a photovoltaic grid-connected inverter capable of stepping up and down with common ground for input and output. Background technique [0002] Traditional energy sources such as coal, oil, and natural gas are increasingly depleted. According to the current proven reserves and consumption levels, oil can be used for 30 to 50 years, natural gas can be used for 60 to 80 years, and coal can be used for about 100 to 200 years. It can be used by humans for about 100 years. In addition, the extensive use of fossil energy has caused serious environmental pollution and exacerbated the greenhouse effect. Therefore, the task of developing new energy sources is very urgent. Compared with traditional fossil energy, solar energy, as a new energy source, has the advantages of being renewable, clean, reliable, and free of greenhouse gas emissions. It is currently a widely ...

AI Technical Summary

Problems solved by technology

[0005] There are mainly two types of non-isolated photovoltaic grid-connected inverters that have been proposed. One is a symmetrical inductance configuration circuit structure. This circuit requires more switching tubes and passive devices, and the system efficiency and reliability are not high; the other is The first is an asymmetric inductance configuration circuit structure, a typical half-bridge circuit requires two electrolytic capacitors, which increases the size and cost of the system and reduces the reliability of the system

And most of the photovoltaic grid-connected inverters that have been proposed can only step down, not boost, and the application range of the circuit is not wide

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