A kind of lcl filter active damping control method and system

Abstract

The invention discloses an active damping control method and system of an LCL filter. The method is as follows: for a three-phase inverter grid-connected through the LCL filter, the three-phase current instantaneous value of a capacitance branch of the LCL filter is acquired by utilization of a current sensor; the obtained three-phase current instantaneous value is used as the input of an active damping feedback link; the control parameter of the active damping feedback link is set; a specific numerical value can be obtained by calculation through a formula according to the damping required bythe system; the output of the active damping feedback link is used as an additional signal, which is added onto a PWM modulation signal output by a current proportional integral controller of a grid-connected inverter; therefore, the damping of the system is increased; and inhibition on the natural resonance of the system is realized. According to the active damping control method and system of the LCL filter in the invention, under multiple working conditions and control parameters, the damping of the grid-connected inverter after the LCL filter is installed can be effectively increased; furthermore, active loss is not generated; the ideal damping control effect is achieved; and steady operation of the grid-connected inverter can be ensured.

Description

technical field [0001] The invention relates to the technical field of stability control of power electronic converters, in particular to an active damping control method and system for an LCL filter. Background technique [0002] It is of great significance to ensure the stable operation of the power grid and improve the power quality to improve the overall benefits of the national economy. As clean renewable energy technologies, the grid-connected capacity of photovoltaic power generation and wind power generation has rapidly increased worldwide in recent years. The grid-connected inverter is an important interface device for photovoltaic units and wind power units to connect to the traditional grid. In order to improve the grid-side current quality and reduce harmonic content, filters are usually installed when the inverter is connected to the grid. Due to the small size, low cost and good attenuation characteristics of the high-frequency components in the current, the L...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide an active damping control method and system for an LCL filter to solve the problem that the damping scheme of the current LCL filter has an unsatisfactory effect

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