Single-phase grid-connected inverter system based on double harmonic filter

Abstract

The invention discloses a single-phase grid-connected inverter system based on a double harmonic filter. The single-phase grid-connected inverter system solves the problems that the active loss is great and the promotion of high-frequency harmonic filter effect is not obvious existing in an existing grid-connected inverter filter system. The single-phase grid-connected inverter system comprises a direct-current power supply (1), a single-phase inverter (2), a double harmonic filter (4) and a single-phase alternating-current power grid (3), wherein the output end of the direct-current power supply (1) is connected with the input end of the single-phase inverter (2); the output end of the single-phase inverter (2) is connected with the single-phase alternating-current power grid (3) through the double harmonic filter (4); an inverter side inductor (Li) of the single-phase double harmonic filter (4) is connected with the output end of the single-phase inverter (2); a grid side inductor (Lg) of the single-phase double harmonic filter (4) is connected with the single-phase alternating-current power grid (3); and a first resonance circuit and a second resonance circuit are connected between the connection point of the inverter side inductor (Li) of the single-phase double harmonic filter (4) and the grid side inductor (Lg) of the single-phase double harmonic filter (4) and the ground in parallel. The harmonic pollution to the power grid when a distributed power supply is connected into the power grid is effectively reduced.

Description

technical field [0001] The invention relates to a grid-connected inverter system used when solar power generation is connected to the existing AC power grid, in particular to a grid-connected inverter system that can effectively filter out high-frequency switching harmonics generated by single-phase grid-connected inverters Grid-connected inverter system. Background technique [0002] When the distributed DC power supply is connected to the existing power grid, the single-phase grid-connected inverter is an indispensable component as the main interface for connecting the distributed power supply to the grid. The single-phase grid-connected inverter converts direct current into single-phase alternating current through pulse width modulation. When the single-phase grid-connected inverter completes the pulse width modulation process, it will inevitably generate high-frequency switching harmonics of different frequencies. Severe high frequency harmonic pollution. High-frequen...

AI Technical Summary

Problems solved by technology

[0003] The invention provides a single-phase grid-connected inverter system based on a double-resonant filter, which solves the technical problems of large active power loss and insignificant improvement of high-frequency harmonic filtering effect in the existing grid-connected inverter filter system

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