Photovoltaic grid-connected inverter and modulation method thereof

Abstract

The invention provides a photovoltaic grid-connected inverter and a modulation method thereof. The photovoltaic grid-connected inverter comprises switch tubes Q1, Q2 and Q3, Q4, Q5 and Q6 and a control signal generation module, wherein the source electrode of the switch tube Q1 is connected with the drain electrode and one end of the alternating current side of the switch tube Q2 separately; the source electrode of the switch tube Q2 is connected with the source electrode of the switch tube Q4 and the drain electrode of the switch tube Q6 separately; the drain electrode of the switch tube Q4 is connected with the source electrode of the switch tube Q3 and the other end of the alternating current side separately; the drain electrode of the switch tube Q3 is connected with the drain electrode of the switch tube Q1 and the source electrode of the switch tube Q5 separately; the drain electrode of the switch tube Q5 is connected with the positive electrode end of the direct current side, and the source electrode of the switch tube Q6 is connected with the negative electrode end of the direct current side; and the control signal generation module is connected with the grid electrodes ofthe switch tubes Q1, Q2 and Q3, Q4, Q5 and Q6 separately. By adopting the photovoltaic grid-connected inverter and the modulation method thereof, the leakage current generated when the photovoltaic grid-connected inverter works can be inhibited.

Description

technical field [0001] The invention relates to the field of photovoltaic grid-connected inverters, in particular to a modulation method for photovoltaic grid-connected inverters. Background technique [0002] In a distributed power generation system that uses solar energy as an input, the grid-connected inverter has the function of converting direct current into alternating current that meets the requirements of the mains and connecting it to the grid. In traditional grid-connected systems, isolated and non-isolated grid-connected inverters with output transformers are often used to generate electrical isolation between the grid and the DC side to ensure personal safety. At the same time, they can also provide voltage matching and grid-connected current DC component suppression. High-frequency transformers increase volume, weight and cost, while high-frequency transformers complicate control and reduce efficiency. Non-isolated grid-connected inverters have become the mains...

AI Technical Summary

Problems solved by technology

Because of the existence of common mode current, the leakage current to the ground will reduce the system efficiency, damage the output power quality, increase the electromagnetic interference of the system, pose a threat to the human body, and form a safety hazard

Moreover, too much leakage current to the ground will cause the saturation of the AC filter, reduce the filtering effect, and may also cause damage to the grid-connected inverter

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