Unlock instant, AI-driven research and patent intelligence for your innovation.

Fault ride-through performance analysis method based on converter grid-connected impedance model

A fault ride-through and impedance model technology, which is applied in the direction of AC network circuits, power transmission AC networks, emergency treatment AC circuit layout, etc., can solve the problem of insufficient analysis of fault ride-through operation performance, discount of performance improvement degree, and influence of fault ride-through performance Issues such as improving the effect

Active Publication Date: 2021-04-09
JINAN UNIVERSITY
View PDF6 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the schemes in the above literatures are usually only obtained from the analysis of the AC side of the converter, specifically based on the analysis of the functions of the converter control and the AC circuit, and the coupling between the AC and DC circuits of the inverter and the influence of the DC side circuit on the fault ride-through operation is usually ignored
[0010] To sum up, under grid fault conditions of unbalanced voltage, the power quality of grid-connected converters deteriorates sharply. So far, although various converter control strategies based on symmetrical components have been proposed to improve fault ride-through performance; however, The coupling effect between AC and DC circuits is usually ignored, which will affect the improvement of fault ride-through performance, especially when the AC-DC coupling effect of the converter is obvious, the degree of performance improvement will be greatly reduced
Furthermore, fault ride-through operations and their performance have not been adequately analyzed

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Fault ride-through performance analysis method based on converter grid-connected impedance model
  • Fault ride-through performance analysis method based on converter grid-connected impedance model
  • Fault ride-through performance analysis method based on converter grid-connected impedance model

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0096] The fault ride-through performance analysis method based on the converter grid-connected impedance model includes the following steps:

[0097] Step 1. Construction of complex function space vector

[0098] 1) Construction of complex function space vector expressions of basic variables

[0099] The converter adopts a three-phase voltage source converter with inner loop DQ current control and outer loop DC voltage control, such as figure 1 As shown, under the grid fault condition, considering the positive sequence fundamental voltage, negative sequence disturbance and zero sequence disturbance components of the common connection point PCC, the common connection point PCC voltage of phase A is expressed as formula (1):

[0100]

[0101] where V 1 Indicates the positive sequence component of the voltage fundamental wave, V n Indicates the negative sequence component of the voltage fundamental wave, V 0 Indicates the voltage fundamental wave zero-sequence air volume; ...

Embodiment 2

[0132] For the control structure with dual current control units based on positive and negative sequence symmetrical components, the basic disturbance component calculation includes the following steps:

[0133] The dual current control structure is usually used to improve the fault ride-through performance of the converter, such as image 3 As shown, the structure of the dual current control unit adopts a typical structure of adjusting the fundamental wave component FC and the negative sequence component NC respectively, and each control unit adopts the same structure as that of the three-phase voltage source converter described in the first step in the first embodiment, That is, using the same figure 2 The same structure as shown;

[0134] In addition to using the formula (3) in step 1 to obtain the fundamental wave component by the delay signal elimination method of the DSC operation unit, an additional DSC operation unit is added to extract the negative sequence componen...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a fault ride-through performance analysis method based on a converter grid-connected impedance model. An inner loop is used for DQ current control, an outer loop is used for DC voltage control, a three-phase voltage source converter of a phase-locked loop for eliminating fault voltage disturbance is used as an example, and multiple coupling influences and the diversity of a control structure are considered at the same time; through modeling of the converter grid-connected impedance model, a circuit model is constructed so as to analyze AC-DC circuit interconnection characteristics of a converter under a power grid fault condition, and by taking a single-current control unit structure and a double-current control unit structure as examples, a grid-connected sequence impedance calculation method when different control strategies are adopted is explained; and basic disturbance component characteristics are calculated based on the sequence impedance so as to evaluate the fault ride-through performance of the converter.

Description

【Technical field】 [0001] The invention relates to converter technology in electrical engineering, in particular to a fault ride-through performance analysis method based on a grid-connected impedance model of the converter. 【Background technique】 [0002] The power quality of grid-connected converters deteriorates dramatically in the event of a grid fault. Such as literature [1] "M.Castilla, J.Miret, J.L.Sosa, J.Matas, and L.G.de Vicu~na,"Grid-fault control scheme forthree-phase photovoltaic converters with adjustable power qualitycharacteristics,"IEEE Trans.Power Electron ., vol.25, no.12, pp.2930-2940, Dec.2010." and literature [2] "H.Chen, H..Lee, P.Cheng, R.Teodorescu, and F.Blaabjerg," Alow-voltage ride-through technique for grid-connected converters with reducedpower transistors stress, "IEEE Trans.Power Electron., vol.31, no.12, pp.8562-8571, Dec.2016.", Converter AC and increased current harmonic distortion in the DC side circuit is one of the typical adverse effec...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): H02J3/00H02J3/36
CPCH02J3/001H02J3/36H02J2203/20Y02E60/60
Inventor 郭焕刘敏刘雄
Owner JINAN UNIVERSITY