Design method, equipment and medium of lcl filter parameters based on damping ratio

Abstract

The present invention provides a method, device and medium for designing LCL filter parameters based on the damping ratio. Firstly, according to the traditional LCL filter design method, the converter side inductance and filter capacitor parameters are selected; then, using the damping ratio, the damping resistance and The value of the inductance on the output side is optimally designed; in addition, an iterative optimization scheme for the total inductance and resonance frequency is also provided. The present invention preferably adopts the optimum damping ratio of 0.28, which can ensure the stable operation of the converter system with the LCL filter with the minimum damping loss. The present invention has few design iterations, can guarantee the high-frequency attenuation design of the LCL filter is accurate, avoids the stability risk introduced by unreasonable damping design, and ensures that the selection of current control parameters is simple and direct, and is suitable for high output side voltage of the LCL filter. occasions with low frequency components.

Description

technical field [0001] The invention relates to the field of converter filter design, in particular to a damping ratio-based LCL filter parameter design method. Background technique [0002] Compared with traditional inductive filters, LCL filters have better attenuation performance for high-frequency current harmonics. In recent years, in order to meet the increasingly stringent grid-connected rules, more and more grid-connected converters have begun to use LCL filters to filter out switching subharmonics in the grid-connected current. However, there is an inherent resonant peak on the amplitude-frequency characteristic curve of the LCL filter, which easily leads to the instability of the converter system and brings challenges to the design of the current controller. In order to ensure the stability of the control, the converter system with the LCL filter generally adopts the method of active damping or passive damping to suppress the resonance peak. [0003] The main adv...

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Problems solved by technology

[0007] 1) The design of passive damping value is inaccurate, which may lead to converter instability or excessive damping loss due to unreasonable damping value;

[0008] 2) Passive damping and high-frequency current attenuation require multiple iterative adjustments, resulting in low design efficiency and poor design accuracy

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