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

An Enhanced Virtual Vector PWM Modulation Method

A modulation method and enhanced technology, applied in output power conversion devices, electrical components, and AC power input to DC power output, etc., can solve the problems of inability to eliminate the accumulated DC offset of the midpoint potential, poor anti-interference ability, etc. , to achieve the effect of simple modulation strategy, high voltage utilization, and volume reduction

Active Publication Date: 2017-11-10
SHANDONG UNIV
View PDF1 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But these two methods belong to open-loop control, the anti-interference ability is poor, and the cumulative DC offset problem of the midpoint potential cannot be eliminated

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
  • An Enhanced Virtual Vector PWM Modulation Method
  • An Enhanced Virtual Vector PWM Modulation Method
  • An Enhanced Virtual Vector PWM Modulation Method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0059] The present invention will be further described below in conjunction with accompanying drawings and examples.

[0060] The traditional NPC three-level inverter adopts LC filter and purely resistive load.

[0061] Based on the modulation method of the above-mentioned NPC three-level inverter, specifically:

[0062] The turn-on time of each switching device of the three-phase bridge arm obtained by the virtual vector PWM modulation method passes d xp , d xn (x∈{a,b,c}) three groups of six modulated waves are responded. According to the detected DC capacitor voltage difference or midpoint potential fluctuation, the corresponding modulation wave is corrected, thereby changing the action time of the small vector, eliminating the cumulative DC offset of the midpoint potential, and the corrected PWM signal obtained through The driving circuit controls the three-level inverter.

[0063] figure 1 It is the structure diagram of NPC three-level inverter, which adopts a single...

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 an enhanced VSVPWM (virtual space vector pulse-width modulation) method. The method comprises steps as follows: space vectors are converted into virtual vectors through PWM, and the action time duty ratio of each virtual vector is calculated; duration per unit values of three-phase output voltage at states P and N are figured out according to the correspondence between the virtual vectors and actual space vectors; the duration per unit values of the three-phase output voltage at the states P and N are used as modulating waves respectively, and a three-phase switch state is obtained; small vector action time is adjusted according to the difference between voltage of two direct-current capacitors or the fluctuation magnitude of midpoint potential, and PWM output of an inverter is obtained. With the adoption of the method, the problem of virtual vector PWM midpoint potential cumulative deviation is solved, midpoint potential balance control can be realized within any modulation degrees, the low-frequency fluctuation of the midpoint potential can be completely eliminated, the anti-interference performance of a system is improved, sizes of the direct-current capacitors are reduced, and the output waveform quality is improved.

Description

technical field [0001] The invention relates to an enhanced virtual vector PWM modulation method. Background technique [0002] Three-level inverters are widely used in high-voltage and high-power occasions due to their advantages such as low voltage for switching devices and high-quality output waveforms. However, the inherent problem of unbalanced midpoint potential has obvious restrictions on the promotion of three-level inverter applications. In recent years, many scholars at home and abroad have done a lot of work on this problem. In terms of topology, a mixed-clamp three-level topology was proposed to realize the automatic balance of the midpoint potential; in terms of modulation methods, methods such as zero-sequence component injection and changing the action time of small vectors were proposed and achieved good results. [0003] In the midpoint potential imbalance problem, the fluctuation of the midpoint potential three times the fundamental frequency is called lo...

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 Patents(China)
IPC IPC(8): H02M7/487
CPCH02M7/487
Inventor 陈阿莲王伟胜张承慧柴锦
Owner SHANDONG UNIV
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