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A fine compensation method for different harmonics used in sapf

A compensation method, sub-harmonic technology, applied in AC network to reduce harmonic/ripple, active power filter, AC network circuit, etc.

Active Publication Date: 2021-04-23
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, harmonic active components are sometimes used for eddy current losses in AC equipment and heat loss due to skin effect of cables

Method used

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  • A fine compensation method for different harmonics used in sapf
  • A fine compensation method for different harmonics used in sapf
  • A fine compensation method for different harmonics used in sapf

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] see figure 1As shown, a refined compensation method for different sub-harmonics used in SAPF, the control block diagram using this method includes five parts: different sub-harmonic active and non-active components detection link, current control link, DC side voltage control link, Sinusoidal pulse width modulation SPWM link, non-linear load contribution k-order harmonic active power flow direction determination link, in this embodiment, SAPF generates a current whose phase is opposite to that of the load harmonic current, which is input to the grid through an LCL filter to offset the grid Harmonic components in the side feeder current.

[0037] Such as figure 2 As shown, the SAPF topological diagram of the input LCL filter circuit in the present invention. The phase voltage reference value of the power grid system is 380V, the frequency is 50Hz, there are 5th harmonic voltage and low 7th harmonic voltage on the grid side, in the LCL filter circuit, , , , DC si...

Embodiment 2

[0062] Under the same conditions, the nominal compensation capacity of SAPF is 20A. According to compensation method 1, SAPF compensates for the 7th and above harmonics in the grid-side feeder current; according to compensation method 2, only 5 harmonics contributed by nonlinear loads can be compensated. The sub-harmonic component and the harmonic component above the 7th order, and the invented fine compensation method can compensate the 5th harmonic component, the 7th non-active component and the 7th-order harmonic component contributed by the nonlinear load.

[0063] With the refined compensation method of the present invention, the harmonic distortion rate of the grid-side feeder current drops from 21.65 to 5.98%, while the traditional compensation method 1 and method 2 drop to 18.83% and 7.48% respectively, and the grid-side feeder current changes with three different compensation methods See Table 3.

[0064] Table 3 Changes in grid-side feeder current THD with three comp...

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Abstract

The invention discloses a refined compensation method for different subharmonics used in SAPF, which mainly includes: collection of feeder voltage on the grid side and load feeder current; detection of active components and non-active components of different subharmonics; Active power flow direction judgment; repeated PI current control controls the generation of harmonic compensation current; DC side voltage PI control link suppresses DC side voltage fluctuations. The method provided by the present invention can determine different compensation schemes by judging the flow direction of each harmonic active power on the load side, and realize fine compensation. The method provided by the invention can reduce the compensation cost of the active power filter on the basis of distinguishing whether the active component of the kth harmonic component causes pollution to the grid side, and under the limited capacity, the compensation method of the invention can effectively reduce the grid side Feeder harmonic distortion (THD).

Description

technical field [0001] The present invention relates to the technical field of power quality control in power systems, and more specifically, relates to a refined compensation method for different subharmonics used in SAPF. Background technique [0002] At present, with the rapid development of power electronic equipment, high-power converter equipment, electric arc furnaces, and a large number of power electronic components are put into use in industrial production. At the same time, a large number of harmonics are injected into the power grid due to power-side transformer and motor failures. It will lead to serious distortion of the grid voltage and affect the normal operation of the grid and loads. In order to improve the operating efficiency of power equipment and improve the power quality, it is necessary to control the harmonic current. Shunt Active Power Filter (SAPF), as a common current harmonic control device, can track and compensate harmonics of different sizes ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/01
CPCH02J3/01H02J2203/20Y02E40/20
Inventor 裘智峰赵鑫涛于晶荣桂卫华
Owner CENT SOUTH UNIV
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