Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Variable-step LMS adaptive harmonic current detection method

A harmonic current and detection method technology, applied in the electric power field, can solve the problems that the convergence speed and steady-state error cannot be guaranteed at the same time, and achieve the effects of good dynamic tracking effect, fast initial convergence speed, and high convergence accuracy

Inactive Publication Date: 2019-01-11
XUZHOU NORMAL UNIVERSITY
View PDF5 Cites 11 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the harmonic detection of power system, the fixed step size algorithm was first proposed. Because the fixed step size cannot guarantee the balance between the convergence speed and the steady state error at the same time, the application of the algorithm is subject to many restrictions.

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
  • Variable-step LMS adaptive harmonic current detection method
  • Variable-step LMS adaptive harmonic current detection method
  • Variable-step LMS adaptive harmonic current detection method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0039] A variable step size LMS adaptive harmonic current detection method, comprising the following steps:

[0040] Step 1. Install a voltage sensor or a current sensor on each phase of the grid system to monitor the load current i of each phase L (t) and system voltage u s (t), subscript L stands for load, S stands for system, variable t is time;

[0041] Step 2. For periodic non-sinusoidal load current i L (t) and the active reference signal x of its fundamental current 1 ,x 1 =sin(ωt),reactive reference signal x 2 ,x 2 = cos(ωt) to perform synchronous sampling, respectively to obtain the discrete value i of the load current at the current sampling time n L (n), the fundamental active discrete value x of the reference signal 1 (n) and fundamental reactive discrete value x2(n); where x 1 is the standard fundamental wave voltage, x 2 is its value after phase shifting by 90°, ω is the fundamental frequency;

[0042] Step 3: Calculate the fundamental active discrete val...

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 variable-step LMS adaptive harmonic current detection method, and belongs to the power technology, provides a new variable-step LMS algorithm under low signal-to-noise ratio conditions for the defects of the existing variable step minimum mean square (LMS) algorithm in the aspect of harmonic current detection. The algorithm takes the ratio K(n) of the error signal e(n) inthe signal to be detected as the feedback quantity of the algorithm, and the parameter changes can be dynamically controlled by establishing a Sigmoid function relation of the mean value estimate between the step size factor and the feedback quantity, so that in the case of large noise interference, the harmonic detection process can guarantee both fast dynamic response speed and higher detectionprecision and better dynamic tracking effect. Proving the harmonic detection algorithm has good harmonic detection performance by simulating the harmonic detection algorithm.

Description

technical field [0001] The invention relates to electric power technology, in particular to a variable step size LMS self-adaptive harmonic current detection method. Background technique [0002] As more and more non-linear power electronic devices are put into application, a large number of harmonics generated thereby directly affect the power quality of the power grid, and the problem of harmonic pollution in the power grid is very serious. Corresponding and effective measures must be taken to suppress harmonic problems, so as to reduce or even avoid the impact of harmonics. As a device that can dynamically compensate harmonics, active power filters have been widely valued and applied. Among them, as the core part of the active filter - the harmonic current detection link, which technology and method to use will have a direct impact on the effect of harmonic suppression, so it is very important to research and improve the real-time detection algorithm of harmonic current ...

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): G01R23/16G01R19/00
CPCG01R19/00G01R23/16
Inventor 胡福年朱娜
Owner XUZHOU NORMAL UNIVERSITY
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap 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