Eureka AIR delivers breakthrough ideas for toughest innovation challenges, trusted by R&D personnel around the world.

Double-voltage closed-loop-control harmonic current detection method and system

A dual-voltage closed-loop, harmonic current technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, reactive power/actual component measurement, etc., can solve detection errors, affect compensation effects, distortion, etc. problem, to achieve the effect of eliminating distortion, wide applicability, and perfect tracking compensation characteristics

Inactive Publication Date: 2015-04-29
STATE GRID CORP OF CHINA +1
View PDF3 Cites 8 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has errors in the detection of fundamental active and reactive currents when the voltage is distorted; secondly, when the load current has a large mutation, the current waveform after compensation will produce a large distortion, which will affect the compensation effect

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
  • Double-voltage closed-loop-control harmonic current detection method and system
  • Double-voltage closed-loop-control harmonic current detection method and system
  • Double-voltage closed-loop-control harmonic current detection method and system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0040] The technical solution of this patent will be further described in detail below in conjunction with specific embodiments.

[0041] i p -i q Detection methods such as figure 1 shown, where e a It is the A-phase voltage signal, and the PLL is a phase-locked loop. The sine and cosine signal generation circuits behind it are controlled by the PLL to generate the sine signal sinωt and the corresponding cosine signal cosωt in the same phase as the A-phase voltage, so as to eliminate the impact of voltage distortion The impact of detection accuracy. According to the definition, i can be calculated p i q , after LPF filtering, i can be obtained p i q DC component of here is corresponding to the current fundamental wave component i af i bf i cf , so by i can be calculated af i bf i cf , and then can calculate i ah i bh i ch .

[0042] When the three-phase voltage is distorted, there is a phase difference between the initial phase angle of the A-phase volta...

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 discloses a double-voltage closed-loop-control harmonic current detection method and system. In an ip-iq detection method, a double-voltage closed-loop control is added so as to eliminate distortion generated during sudden change of load current; a novel low-pass filtering-based a-phase positive sequence voltage extracting unit is used for replacing a PLL phase-locked loop in the ip-iq detection method; under the condition of three-phase voltage distortion, the a-phase positive sequence voltage can be still normally extracted so as to accurately detect harmonic and reactive current. Simulating and studying results that by the double-voltage closed-loop-control harmonic current detection method, the distortion of the current during the sudden change of the load current can be eliminated, and under the condition of the voltage distortion, the harmonic component and the reactive current can be still correctively detected; under the condition that an instruction current has a very large sudden change, DC-side voltage closed-loop control and pressure-equalizing closed-loop control of upper and lower capacitors are added, so that zigzag distortion of grid current during the sudden change of the load current is avoided, and tracking and compensating characteristics are improved; the double-voltage closed-loop-control harmonic current detection method has wide applicability.

Description

technical field [0001] The invention relates to a method for detecting a harmonic current in a power system, in particular to a method and a system for detecting a harmonic current under dual-voltage closed-loop control. Background technique [0002] With the more extensive use of power electronic devices, electric energy has been more fully applied, but accompanied by more and more non-linear and impact loads, the harmonic pollution in the power grid is becoming more and more serious, causing people's attention. In the research of such harmonic suppression and reactive power compensation devices, the power active filter (APF) has been widely used. Compared with passive filters, active filters have the advantages of good dynamic response characteristics, and filtering characteristics are not affected by system impedance. The harmonic current detection method adopted by the APF directly determines the detection accuracy and tracking speed of the harmonics, and is the key to...

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
Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/01
CPCG01R19/06H02J3/01Y02E40/40
Inventor 刘航王春芹陈宁
Owner STATE GRID CORP OF CHINA
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com