Method for improving stability of energy storage inverter grid-connected system based on current mode control

Abstract

The invention discloses a method for improving the stability of an energy storage inverter grid-connected system based on current type control. The method comprises the following steps: analyzing the influence of energy storage inverter control parameters on the stability of the grid-connected system by adopting a Nyquist stability criterion of a cascade system based on a pre-constructed energy storage inverter output impedance model; determining and modifying energy storage inverter control parameters for improving the stability of the grid-connected system according to the influence of the energy storage inverter control parameters; judging whether the stability of the grid-connected system is effectively improved after the control parameters of the energy storage inverter are modified, and if not, outputting an impedance model based on the pre-constructed active damping control energy storage inverter; an energy storage inverter output impedance model based on active damping control analyzes the influence of active damping control parameters on the stability of a grid-connected system by adopting a Nyquist stability criterion of a cascade system; the active damping control parameters for improving the stability of the grid-connected system are determined and modified according to the influence of the active damping control parameters, and the stability of the grid-connected system can be effectively improved.

Description

technical field [0001] The invention relates to a method for improving the stability of an energy storage inverter grid-connected system based on current-type control, and belongs to the technical field of power grids. Background technique [0002] With the sharp reduction of fossil resources such as coal and petroleum, the power generation and grid connection of renewable energy such as wind and light have become a research hotspot. Almost all renewable energy is connected to the grid through power electronic converters. The access of a large number of power electronic devices makes the system contain more high-frequency harmonic components, which are prone to harmonic oscillation and cause grid voltage and grid-connected current distortion. , thereby reducing the stability of the grid-connected system. [0003] In order to cope with the access of random power sources such as wind and solar with increasing penetration rate, the system usually uses an energy storage system ...

AI Technical Summary

Problems solved by technology

However, due to the influence of parameters such as grid transmission cables, the actual grid impedance is not zero, so there will be an intersection point between the grid impedance and the inverter output impedance in the frequency domain

If the grid impedance is too large, or the design of the inverter control parameters is unreasonable, there may be too small a phase angle margin, and harmonic oscillation occurs near the frequency of the impedance intersection point, resulting in instability of the grid-connected system

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