Novel three-level NPC current converter modulation and midpoint level control strategy

A potential control and three-level technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., can solve problems such as high switching loss, high switching frequency, and low efficiency

Inactive Publication Date: 2018-11-06
XIAN UNIV OF TECH +1
View PDF4 Cites 14 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a novel three-level NPC converter modulation and midpoint potential control strategy, which

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
  • Novel three-level NPC current converter modulation and midpoint level control strategy
  • Novel three-level NPC current converter modulation and midpoint level control strategy
  • Novel three-level NPC current converter modulation and midpoint level control strategy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0073] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0074] Such as figure 1 As shown, it is a schematic diagram of a diode-clamped three-level converter in the present invention, including a three-phase AC part (if it is a three-level inverter structure, the three-phase AC part is a load; if it is a three-level Rectifier, static var generator and other devices, the three-phase AC part is AC source plus three-phase AC smoothing reactor), the external part of the three-level DC side (if it is a three-level inverter structure, the external part of the DC side Part of it is a DC voltage source, which can be an actual power supply or a DC source obtained by rectifying an AC power supply; if it is a three-level rectifier structure, the external part of the DC side is a load; if it is a three-level static var generator, there is no external part on the DC side), the main circuit part of the three-le...

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 novel three-level NPC current converter modulation and midpoint level control strategy comprising the steps of 1, firstly acquiring an upward modulating wave U*p and a downward modulating wave U*n; 2, decomposing the upward modulating wave U*p into U*p1 and U*p2, decomposing the downward modulating wave U*n into U*n1 and U*n2, and thus acquiring an analytic expression ofthe downward modulating waves under different modulating degrees m; 3, using a model prediction control method, and predicting the midpoint voltage of a (k+1) moment and a (k+2) moment; and 4, comparing the midpoint voltage of the (k+1) moment and the (k+2) moment with a reference voltage Uref, and then deciding whether to switch the modulating wave; then outputting a final PWM pulse to the three-level NPC current converter after the modulating wave is compared with a carrier wave. The control strategy provided by the invention selects the modulating wave through predicting the midpoint voltage values of two future moments to serve as a criterion; and provided is the three-level NPC current converter modulation and midpoint level control strategy which achieves balanced midpoint voltage, small switching loss and high efficiency under full modulating degrees and full power factors.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a modulation and midpoint potential control strategy of a novel three-level NPC converter. Background technique [0002] In recent years, with the wide application of three-level neutral point clamped (NPC) converters in photovoltaic grid-connected systems, the technology of three-level NPC converters has become increasingly mature, but its inherent neutral point potential balance problem Still needs to be perfected. [0003] At present, the modulation methods of the three-level NPC converter mainly include the carrier PWM method and the space vector PWM (spacevector PWM, SVPWM) method. [0004] Space vector PWM (SVPWM) has been widely welcomed due to its high voltage utilization rate and flexible vector selection, but this method has complex algorithms and a large amount of calculation. On the contrary, the basic carrier PWM has the advantages of simple a...

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): H02M7/487
CPCH02M7/487
Inventor 李宁李婉婷张辉王倩高亮何俊成范聪
Owner XIAN UNIV OF TECH
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
Try Eureka
PatSnap group products

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

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap