Current source grid-connected inverter based on transformer filtering and dual-carrier modulation method thereof

Abstract

The invention provides a current source grid-connected inverter based on transformer filtering and a dual-carrier modulation method thereof, and the current source grid-connected inverter is characterized in that a positive electrode and a negative electrode of a DC source are connected to a reverse blocking type full-bridge circuit through a DC inductor, and the output end of the reverse blocking type full-bridge circuit is connected to a power grid through an isolation transformer filter network; the isolation transformer filter network comprises an isolation transformer and a leakage inductor thereof which are connected in series at the output end of the reverse-blocking full-bridge circuit, and a filter capacitor which is connected in parallel at the output end of the reverse-blocking full-bridge circuit; the secondary side of the isolation transformer is connected to a power grid; and carrying out dual-modulation wave dual-carrier unipolar PWM modulation on the current source grid-connected inverter based on transformer filtering. According to the invention, electrical isolation is realized by adding transformer filtering in combination with dual-modulation-wave dual-carrier unipolar PWM modulation, and a CL filter is formed by transformer leakage inductance and a filter capacitor to suppress harmonic current, so that the leakage current and the total harmonic distortion content are reduced.

Description

technical field [0001] The invention relates to the technical field of modulation strategy application of photovoltaic inverters, in particular to a current source grid-connected inverter based on transformer filtering and a dual-carrier modulation method thereof. Background technique [0002] The transformer size and leakage inductance of the traditional current source photovoltaic grid-connected inverter without a transformer are large, resulting in serious power loss; the non-isolated current source inverter has inherent leakage current defects, which pose a safety hazard to the power grid. [0003] Therefore, how to provide a current source grid-connected inverter based on transformer filtering and its The dual-carrier modulation method is an urgent problem to be solved by those skilled in the art. Contents of the invention [0004] In view of this, the present invention provides a current source grid-connected inverter based on transformer filtering and its dual-carr...

AI Technical Summary

Problems solved by technology

[0002] Traditional current source photovoltaic grid-connected inverters without transformers have large transformer volume and leakage inductance, resulting in serious power loss; non-isolated current source inverters have inherent leakage current defects, which pose a safety hazard to the grid

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