A method for controlling a grid-connected converter

Abstract

The invention discloses a method for controlling a grid-connected converter, comprising the following steps: step S1, establishing a model of the grid-connected converter, and calculating its output transfer function; step S2, determining the harmonic frequency range to be suppressed, and setting Determine the corresponding PI parameters, initial temperature, initial value of virtual resistance, value range of virtual resistance, number of iteration steps and stop criterion; step S3, take the filter effect function to be optimized as the objective function, and take the value of virtual resistance as Decision variables, using the annealing function and the annealing end criterion as constraints to establish the optimization model of the grid-connected converter; step S4, using the simulated annealing algorithm to optimize the virtual resistance of the optimization model, and determine the virtual resistance value . The invention can enable the grid-connected converter to have output active power and harmonic suppression functions at the same time, improve the utilization rate of the traditional grid-connected converter, and reduce the harmonic control cost of the grid.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a control method for a grid-connected converter. Background technique [0002] Although a large number of distributed power sources connected to the distribution network can effectively alleviate the local congestion problem of the power grid and realize functions such as on-site compensation of active and reactive power, but due to the intermittent and uncertain output power of the distributed power generation system, and The use of a large number of power electronic converters has brought serious harmonic pollution problems to the traditional distribution network. There are also a large number of nonlinear loads in the distributed power grid, which aggravates the problems of harmonic pollution and reactive power shortage. Harmonic pollution will affect the normal operation of power system devices and even the entire distribution network system, and must be treated. [0...

AI Technical Summary

Problems solved by technology

[0003] Traditional harmonic control devices are divided into two types: passive filters and active filters. Passive filters have a simple structure, but their compensation characteristics are affected by the impedance of the grid, and they tend to resonate with the system during operation, and can only compensate for fixed Some harmonics; based on power electronics technology, the active filter can compensate the harmonic current of a specific line by taking the harmonic current as the compensation object. Promote apps within

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