A neutral-point potential balancing technique implemented at the front end in back-to-back-connected three-level converter

2008 ◽  
Author(s):  
Kai Tian ◽  
Mingyan Wang ◽  
Songbin Liu
Keyword(s):  
Neutral Point ◽  
Front End ◽  
Point Potential ◽  
Level Converter

An Improved VSVPWM Strategy of Considering Neutral-Point Potential Balancing in Three-Level NPC Converter

2014 ◽  
Vol 496-500 ◽  
pp. 1079-1083
Author(s):  
Shi Weng Gui ◽  
Lu Wang ◽  
Sheng Hua Huang
Keyword(s):  
Neutral Point ◽  
Virtual Space ◽  
Space Vector Modulation ◽  
Space Vector ◽  
Multilevel Converters ◽  
Control Approach ◽  
Research Fields ◽  
Point Potential ◽  
Vector Modulation ◽  
Level Converter

Neutral-point (NP)-clamped three-level converter is a widely used topology in the research fields of the multilevel converters, which suffers from the NP voltage drift as its main technical drawback. In theory, it is based on the fact that the virtual space vector modulation approach could completely control the balance of neutral-point potential, so this paper introduces a improved control strategy of neutral-point potential balancing in three-level converter, which combines the space vector modulation approach based on virtual vectors with the algorithm of modifying small vectors pairs distribution time accurately. Relative to the traditional proposed algorithm of setting voltage tolerance range to modify small vectors pairs distribution time,the performance of algorithm of capacitor charge balancing is better and its accuracy of control is more precise. The feasibility of the proposed control approach has been verified via experiment results.

scholarly journals Neutral Point Potential Control for Three Phase 3 - level Neutral Point Clamped Active Front End Converter

2017 ◽  
Vol 9 (2) ◽  
pp. 342-363 ◽  
Author(s):  
Amit Ojha ◽  
◽  
Pradyumn Chaturvedi ◽  
Arvind Mittal ◽  
S Jain ◽  
...  
Keyword(s):  
Neutral Point ◽  
Phase 3 ◽  
Potential Control ◽  
Front End ◽  
Point Potential ◽  
Three Phase

scholarly journals Design of Control System Using Online Tuning of PI Controllers for Three-Phase Active Front End Neutral Point Clamped Three-Level Converter

2020 ◽  
Vol 53 (6) ◽  
pp. 869-882
Author(s):  
Amit Ojha
Keyword(s):  
Control System ◽  
Design Procedure ◽  
Accurate Method ◽  
Good Choice ◽  
Neutral Point ◽  
Front End ◽  
Three Phase ◽  
Pi Controllers ◽  
Level Converter ◽  
Online Tuning

In conventional DC link AC-AC converter system, uncontrolled front end converter has inherent problem of power quality. To overcome the problem associated with uncontrolled front end converter, multilevel front end converter will be good choice for high power applications. In the paper, unity power factor control system (UPC) for active front end (AFE) neutral point clamped (NPC) 3-level converter is presented. PI controllers are used in UPC and for tuning of PI controllers it is essentially required to know the different time constants with their gains exactly for evaluating the optimized controller parameters for steady operation of the NPC rectifier. In this paper a simplified and accurate method of online tuning of PI controllers in UPC is derived and implemented for three phase AFE NPC 3-level converter. Complete design procedure for the design of control system for AFE NPC 3-level is also presented in this paper. Based on developed model, simulations are carried in MATLAB/SIMULIK environment. Experimentation results confirm the simulation results.

Neutral Point Potential Balance of Dual Three-Level Converter Based on Fuzzy Logic Control Strategy

2014 ◽  
Vol 644-650 ◽  
pp. 3788-3792
Author(s):  
Xiao Lin Zhang ◽  
Jing Bo Shi
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Control ◽  
Neutral Point ◽  
Logic Control ◽  
Point Potential ◽  
The Status ◽  
Four Quadrant ◽  
Balance Factor ◽  
Level Converter ◽  
The Relationship

In dual three-level converter system, the rectifier and inverter have unified problems of the neutral point potential imbalance.This paper analyzed the reasons of imbalance of neutral point potential in detail and summarized the relationship between vector status and four-quadrant status of three-level converters.Then a method based on fuzzy logic control (FLC) is proposed,which could be automatically adjust the balance factor.Combined the balance factor with the status of the converter the duration of positive and negative small vectors action could be obtained.Finally the balance of the neutral point potential is achieved.This method could be generally used on rectifier and inverter.At last, the simulation was done on both inverter and rectifier side.The results verified the feasibility of the proposed method.

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