Method and system for judging small-disturbance inter-harmonic amplification phenomenon of inverter

Abstract

The invention provides a method and system for judging a small-disturbance inter-harmonic amplification phenomenon of an inverter. The method comprises an inverter model simplification and associationestablishment step in which a main circuit and a control structure of the inverter are simplified into a phase-locked loop so as to obtain a phase-locked loop simplification model of the inverter; anassociation establishment step in which an association analytical expression of an output quantity of the inverter and a phase-locked loop linear transfer function under small disturbance is established by using the phase-locked loop simplification model; and a judgment step in which the inter-harmonic amplification range of the output quantity of the inverter under the small disturbance and thedisturbance frequency with the most obvious amplification effect are judged according to the association analytical expression. According to the invention, the inter-harmonic amplification range of the output quantity of the inverter under small disturbance and the disturbance frequency with the most obvious amplification effect can be quickly and accurately determined only by utilizing the traditional phase-locked loop linear transfer function.

Description

technical field [0001] The invention relates to the field of alternating current power generation and distribution, in particular to a method and system for judging harmonic amplification phenomena between small disturbances of inverters. Background technique [0002] The grid connection of new energy power generation is not only conducive to the adjustment of the primary energy structure of the power system, but also helps to reduce the carbon emission level of power generation and promote the clean grid connection of electric energy. With the maturity of new energy power generation technology, its cost per unit of electricity has been greatly reduced, and it has gradually become more competitive with traditional fossil energy in terms of economy. The high proportion penetration of new energy power generation in the power system has become a major feature of the future power system, but limited by natural conditions, the randomness, uncertainty, and high proportion of new e...

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Problems solved by technology

However, using the impedance model established in this document to determine the inverter output under small disturbances has two main disadvantages: first, this document establishes an impedance model, and the disturbance voltage needs to be taken into account when determining the inverter output. Perform numerical calculations with the analytical model to indirectly obtain the output of the inverter; second, the impedance model established in this document only considers the impedance analytical value corresponding to the disturbance frequency, and the new frequency output by the inverter phase-locked loop’s own characteristics Portions are not taken into account

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