Analysis of 12-pulse rectifier operation under balanced and unbalanced voltage source with input impedance

2011 ◽  
Author(s):  
Mahmoud Kassas
Keyword(s):  
Input Impedance ◽  
Voltage Source ◽  
Unbalanced Voltage

Disturbance-observer based control of voltage-source-converter under unbalanced voltage conditions

2017 ◽  
Vol 14 (6) ◽  
pp. 522-531 ◽  
Author(s):  
Akhtar Rasool ◽  
Esref Emre Ozsoy ◽  
Fiaz Ahmad ◽  
Asif Sabanoviç ◽  
Sanjeevikumar Padmanaban
Keyword(s):  
Disturbance Observer ◽  
Operating Conditions ◽  
Voltage Source ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
Negative Sequence ◽  
First Order ◽  
Unbalanced Voltage ◽  
Low Pass

Purpose This paper aims to propose a novel grid current control strategy for grid-connected voltage source converters (VSCs) under unbalanced grid voltage conditions. Design/methodology/approach A grid voltage dynamic model is represented in symmetrical positive and negative sequence reference frames. A proportional controller structure with a first-order low-pass filter disturbance observer (DOB) is designed for power control in unbalanced voltage conditions. This controller is capable of meeting the positive sequence power requirements, and it also eliminates negative sequence power components which cause double-frequency oscillations on power. The symmetrical components are calculated by using the second-order generalized integrator-based observer, which accurately estimates the symmetrical components. Findings Proportional current controllers are sufficient in this study in a wide range of operating conditions, as DOB accurately estimates and feed-forwards nonlinear terms which may be deteriorated by physical and operating conditions. This is the first reported scheme which estimates the VSC disturbances in terms of symmetrical component decomposition and the DOB concept. Originality/value The proposed method does not require any grid parameter to be known, as it estimates nonlinear terms with a first-order low-pass filter DOB. The proposed control system is implemented on a dSPACE ds1103 digital controller by using a three-phase, three-wire VSC.

Analysis of Noncharacteristic Harmonics Generated by Voltage-Source Converters Operating Under Unbalanced Voltage

2017 ◽  
Vol 32 (2) ◽  
pp. 951-961 ◽  
Author(s):  
Claudionor F. Nascimento ◽  
Edson H. Watanabe ◽  
Oumar Diene ◽  
Alvaro B. Dietrich ◽  
Alessandro Goedtel ◽  
...  
Keyword(s):  
Voltage Source ◽  
Voltage Source Converters ◽  
Unbalanced Voltage

Analysis of non-characteristic harmonics generated by voltage-source converters operating under unbalanced voltage

2017 ◽  
Author(s):  
Claudionor Nascimento ◽  
Edson Watanabe ◽  
Oumar Diene ◽  
Alvaro Dietrich ◽  
Alessandro Goedtel ◽  
...  
Keyword(s):  
Voltage Source ◽  
Voltage Source Converters ◽  
Unbalanced Voltage

Input Impedance Modeling of Single-Phase Voltage Source Rectifier With Consideration of FrequencyCoupling Effect

2020 ◽  
Author(s):  
Jianheng Lin ◽  
Mei Su ◽  
Yao Sun ◽  
Shiming Xie
Keyword(s):  
Input Impedance ◽  
Single Phase ◽  
Coupling Effect ◽  
Voltage Source ◽  
Phase Voltage ◽  
Impedance Model ◽  
Grid Impedance ◽  
Impedance Modeling ◽  
Frequency Coupling ◽  
Time Periodicity

Time-periodicity and non-linearity pose a challenge to the precise input impedance modeling of single-phase power converters. In this study, a precise input impedance model with measurability of the single-phase voltage source rectifier (VSR), which considers the frequency-coupling effect (FCE), is established. Meanwhile, it is revealed that the rectifier input impedance is dependent of the grid impedance. In the proposed modeling approach, only Laplace transform and frequencyshifting operation are required, which avoids the complicated convolution calculation in the frequency domain. In addition, the influence of grid impedance on the input impedance is studied. Simulations are conducted to verify the effectiveness of the proposed method. <br>

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