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1 – 5 of 5Fardin Hasanzad, Hasan Rastegar and Mohammad Pichan
This paper aims to investigate the common-mode voltage (CMV) issue of a three-phase four-leg voltage-source inverter. A new space vector modulation method, named as…
Abstract
Purpose
This paper aims to investigate the common-mode voltage (CMV) issue of a three-phase four-leg voltage-source inverter. A new space vector modulation method, named as three-dimensional active zero state Pulse-width modulation (PWM) (3-D AZSPWM), is proposed to reduce the CMV level.
Design/methodology/approach
PWM is a general method to generate the switching signals of the power converters in order to obtain high-quality output voltages. However, the CMV produced by PWM methods has become a serious problem. 3-D AZSPWM is proposed to solve this issue. In 3-D AZSPWM, instead of using zero voltage vectors with high CMV level, appropriate complementary non-zero vectors are introduced to synthesize reference vector. The proposed method is classified into four types of AZSPWM1(a), AZSPWM1(b), AZSPWM2(a) and AZSPWM2(b) based on different complementary vectors chosen for each type. An extend software simulation using MATLAB/Simulink is performed to verify the superior performance of the proposed methods.
Findings
Compared to other reduced CMV methods, the proposed method not only reduces the CMV but also retains the positive characteristics of the three-dimensional classical space vector PWM (3-D CSVPWM).
Originality/value
The proposed method does not suffer from linear modulation region limitation and also does not impose additional switching loss. Furthermore, calculated output voltage harmonic distortion factor illuminates acceptable quality of output voltage produced by the proposed method.
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Keywords
Ionel Vechiu, Octavian Curea, Alvaro Llaria and Haritza Camblong
Nowadays, distributed generation and microgrids (MGs) are becoming an important research line because of their peculiar characteristics. MGs are composed of small power sources…
Abstract
Purpose
Nowadays, distributed generation and microgrids (MGs) are becoming an important research line because of their peculiar characteristics. MGs are composed of small power sources which can be renewable, placed near customer sites. Moreover, they have the inherent property of islanding: the disconnection of either the MG from the main grid or a part of a MG from the rest of the MG. The purpose of this paper is to study two different control strategies allowing grid connected and islanding operation of the MG.
Design/methodology/approach
In this paper, the behaviour of a particular MG during grid connected and islanding operation is investigated. The studied MG is based on different energy sources: a wind turbine, a photovoltaic array, a backup diesel generator and a storage system. The renewable sources and the storage system are connected on a DC bus which is interconnected with a main grid through a voltage source inverter (VSI). The attention focuses on the control technique of the VSI during grid connected and islanding operation of the MG. The behaviour of the AC signals on the point of common coupling between the MG and the main grid as well as the DC signals on the DC bus on which are connected renewable energy sources of the MG has been investigated by simulation using a MATLAB/Simulink model.
Findings
For the investigated MG, the simulation results show that using a single master VSI and classical control strategies, it is possible to have a good power quality on the MG during grid connection and islanding operation.
Originality/value
This paper investigates the behaviour of a particular MG in order to analyse two different control strategies allowing grid connected and islanding operation.
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Akhtar Rasool, Esref Emre Ozsoy, Fiaz Ahmad, Asif Sabanoviç and Sanjeevikumar Padmanaban
This paper aims to propose a novel grid current control strategy for grid-connected voltage source converters (VSCs) under unbalanced grid voltage conditions.
Abstract
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.
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Ananthan Nagarajan, Sivachandran P., Suganyadevi M.V. and Muthukumar P.
The purpose of this study is to help the researchers, public, industries and government to realize the tremendous trends to improve the power quality of both sources and load side.
Abstract
Purpose
The purpose of this study is to help the researchers, public, industries and government to realize the tremendous trends to improve the power quality of both sources and load side.
Design/methodology/approach
The work carried out in the Facts device and power quality issues.
Findings
Maintaining the quality of electric power is always a challenging task. The effect of power electronics devices leads to improper power quality. The use of FACTS devices is preferably the best approach to treat power-quality-related problems. Usually, all FACTS devices are constructed to operate on the side of either the source side or the load.
Originality/value
This paper explores a broad comprehensive study of various types of power quality problems and classification of FACTS devices with its recent developments. Furthermore unified power quality conditioner (UPQC) is particularly reviewed to highlight the advantages over other compensating devices. An exhaustive study of literature has been carried out and most significant concepts are presented
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Massimo Barcaro and Nicola Bianchi
The purpose of this paper is to give an overview of the design issues of permanent magnet machines for the hybrid electric and plug‐in electric vehicles, including railway…
Abstract
Purpose
The purpose of this paper is to give an overview of the design issues of permanent magnet machines for the hybrid electric and plug‐in electric vehicles, including railway traction and naval propulsion.
Design/methodology/approach
Focus is given on both synchronous permanent magnet and reluctance machines. An overview of the design rules are provided, covering the topics of: fractional‐slot windings, fault‐tolerant configurations, flux‐weakening capability, and torque quality.
Findings
The peculiarities of these machines and the advanced design considerations to fit the automotive requirements are analyzed.
Originality/value
The paper includes a wide description of innovative electrical machines for electric vehicles, including not only the traction capability, but also analysis of features as weight reduction, torque ripple reduction, increase of fault tolerance, and so on.
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