Implementation of drirect torque control method on brushless doubly fed induction machines in unbalenced situations

, Article 7th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2016, 16 February 2016 through 18 February 2016 ; 2016 , Pages 70-75 ; 9781509003754 (ISBN) Ghaffarpour, A ; Barati, F ; Oraee, H ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2016

Abstract

This paper presents a new method for implementing the direct torque control (DTC) on the brushless doubly fed induction machines (BDFM) in presence of turbulence in voltage grid. It is supposed irrupts in three phase voltage grid suddenly. Effects of these events on closed-loop operation are inevitable and in some cases could lead to system instability. It presumed that grid voltages disturbance effect on back-To-back converter's outputs is negligible. Control of a complex machine is problematic. Hence, firstly has explained performance of the control method on BDFM, Proposed a new method for reducing turbulence effects of system operation afterward. Simulation results on BDFM model with...

An integrated and optimal joint scheduling of energy resources to feed electrical, thermal and potable water demands in remote area

, Article Iranian Journal of Electrical and Electronic Engineering ; Volume 12, Issue 4 , 2016 , Pages 281-291 ; 17352827 (ISSN) Ghaffarpour, R ; Mozafari, B ; Ranjbar, A. M ; Sharif University of Technology

Iran University of Science and Technology 2016

Abstract

The continuous spread of distributed energy resources (DERs) such as combined heating and power (CHP), diesel generators, boilers and renewable energy sources provide an effective solution to energy related problems to serve the power and heat demands with minimum cost. Moreover, the DERs may play a significant role for supplying power and heat in rural areas, where grid electricity is not available. Also, some dry areas may face water scarcity and salinity problems. So, one important solution is the use of DERs to drive desalination units in order to solve water scarcity and salinity problems. In this study, the optimal scheduling of DERs and reverse osmosis (RO) desalination unit that feed...

Evaluation of dissimilar welds of 5083-H12 and 6061-T6 produced by friction stir welding

, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 44, Issue 8 , 2013 , Pages 3697-3707 ; 10735623 (ISSN) Ghaffarpour, M ; Kolahgar, S ; Dariani, B. M ; Dehghani, K ; Sharif University of Technology

2013

Abstract

In the present study, the dissimilar aluminum alloys of 5083-H12 and 6061-T6 were joined by friction stir welding (FSW). Then, the design of experiments (DOE), the Box-Benken method, and the response surface methodology (RSM) were used to optimize the effective parameters of the FSW process. The optimized parameters that led to the maximum tensile strength in dissimilar friction stir welded sheets were determined. The predicted results were then compared with those measured experimentally. The results show that there is good agreement between the predicted and measured amounts. By applying the limit dome height (LDH) test, the formability of friction stir welded sheets was studied. During...

Resilience-oriented distribution network optimal planning to improve the continuity of power supply

, Article International Journal of Ambient Energy ; 2018 , Pages 1-9 ; 01430750 (ISSN) Ghaffarpour, R ; Jannati Oskuee, M. R ; Ranjbar, A. M ; Sharif University of Technology

Taylor and Francis Ltd 2018

Abstract

A widely dispersed asset, electric grid has enormous impacts on people’s lives. Recently occurred various high-impact low-probability (HILP) threats have raised the concerns about the classical reliability-oriented view. Therefore, withstanding unexpected and less frequent severe situations still remain a significant challenge. As a critical infrastructure (CI), power systems are more and more expected to be resilient to HILPs. So, utilities put their endeavours to harden enough their networks against HILPs. In this regard, there is a great need to a methodology able to optimise the hardening programme investments. This scheme could potentially save a large amount of money, as well as...

Resilience-oriented distribution network optimal planning to improve the continuity of power supply

, Article International Journal of Ambient Energy ; Volume 41, Issue 4 , 2020 , Pages 466-474 Ghaffarpour, R ; Jannati Oskuee, M. R ; Ranjbar, A. M ; Sharif University of Technology

Taylor and Francis Ltd 2020

Abstract

A widely dispersed asset, electric grid has enormous impacts on people’s lives. Recently occurred various high-impact low-probability (HILP) threats have raised the concerns about the classical reliability-oriented view. Therefore, withstanding unexpected and less frequent severe situations still remain a significant challenge. As a critical infrastructure (CI), power systems are more and more expected to be resilient to HILPs. So, utilities put their endeavours to harden enough their networks against HILPs. In this regard, there is a great need to a methodology able to optimise the hardening programme investments. This scheme could potentially save a large amount of money, as well as...

Resilience oriented water and energy hub scheduling considering maintenance constraint

, Article Energy ; Volume 158 , 2018 , Pages 1092-1104 ; 03605442 (ISSN) Ghaffarpour, R ; Mozafari, B ; Ranjbar, A. M ; Torabi, T ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

In this paper resilience oriented water and energy hub scheduling for a remote area is presented. The optimal operation scheduling considering maintenance programming and reliability indices are presented. Demands which include electricity, heat and drinking waters are supplied by diesel generators, boilers, combined heat and power units, and drinking water sources such as desalination units and transferring water. The considered system contains renewable energy resources such as wind turbine and photovoltaic arrays as well as electrical storage units. In order to enhance resiliency of system against forced outages of components and regular maintenance programs, maintenance constraints and...

Improve the Direct Torque Control Method for Brushless Doubly Fed Induction Machines

, M.Sc. Thesis Sharif University of Technology Ghaffarpour, Ali (Author) ; Oraee Mirzamani, Hashem (Supervisor) ; Barati, Farhad (Co-Advisor)

Abstract

The Brushless Doubly Fed Induction Machine (BDFIM) has the potential to be used as a generator or motor in adjustable speed variables. But the most important application for the BDFM is to work as a wind generator. Due to this ability it can be considered as a rival for the Doubly Fed Induction Generator (DFIG) that is the most common type of the wind power generators nowadays. Because of problems of relater to brushes in DFIG, the BDFM has more resisted structure compared to the DFIG. Thanks to the special “nested loop” structure of rotor and two different coils on the stator without direct coupling between them, three different operation modes are possible for the BDFM.The synchronous...

Friction stir welding parameters optimization of heterogeneous tailored welded blank sheets of aluminium alloys 6061 and 5083 using response surface methodology

, Article Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture ; Volume 226, Issue 12 , 2012 , Pages 2013-2022 ; 09544054 (ISSN) Ghaffarpour, M ; Dariani, B. M ; Hossein Kokabi, A ; Razani, N. A ; Sharif University of Technology

2012

Abstract

Today, tailored welded blank sheets have found various applications in automotive, aeronautic and many other industrial fields. One of the most efficient methods for production of tailored welded blank sheets is application of the friction stir welding process. In the present article, the effect of friction stir welding parameters on the microstructure and mechanical properties of heterogeneous tailored welded blank sheets made from aluminium alloys of types 5083-H12 and 6061-T6 with the similar thickness of 1.5 mm is studied. The considered parameters are rotational speed of the tool, linear speed of the tool, pin diameter and shoulder diameter. In order to come by a tailored welded blank...

Technical English for mechanical engineers

, Book Alemi, Minoo ; Meghdari,Ali

Sharif University Press 2014

Abstract

Local educational institutions produce in-house English for Specific Purpose (ESP) materials according to the curriculum policies designated and developed by the Ministry of Higher Education In Iran. To this end, this book aims to be used in the Iranian setting at the tertiary level for undergraduate students majoring in Mechanical Engineering. Moreover, the style of English usage in this ESP textbook is American.
Regarding the content of the textbook, it has both thematic organizations in which the topics are relevant and includes sufficient treatment of the target language areas necessary for the students. The principle organizing approach of this textbook is theme-based. In addition,...

Feedback control of the neuro-musculoskeletal system in a forward dynamics simulation of stair locomotion [electronic resource]

, Article Proc. of IMechE Part H: Journal of Engineering in Medicine ; 2009, Vol. 223, No. 6, pp. 663-675 Journal of NeuroEngineering and Rehabilitation ; Volume 11, Issue 1, 30 April 2014, Article number 78 Selk Ghafari, A. (Ali) ; Meghdari, Ali ; Vossough, Gholam Reza ; Sharif University of Technology

Abstract

The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of...

Design and Construction of a Soft Actuated Exoskeleton for Hand Rehabilitation of Stroke Patients

, M.Sc. Thesis Sharif University of Technology Razavi Zadehgan, Ali Akbar (Author) ; Ghafari, Ali (Supervisor) ; Meghdari, Ali (Supervisor)

Abstract

The main goal of this thesis is the design and development of a rehabilitation device for helping patients “to improve blood circulation” & retain and recover their abilities if possible that were lost during the stroke or a accident like that (my research in karaj/iran shows that it is possible by just movement of the specific body part). The focus is on hand in this thesis because Injuries to the hand are common and can be very debilitating since our hands are our primary means for interacting with our world. For rehabilitation in case of human hand there are several practices that should be done for patients either in home or in a rehabilitation center, time and money that is supposed to...

Silica chloride/wet SiO2 as a novel heterogeneous system for the deprotection of acetals under mild conditions [electronic resource]

, Article Phosphorus, Sulfur, and Silicon and the Related Elements ; Volume 178:2667-2670, Issue 12, 2003 Mirjalili, B. F. (BiBi Fatemeh) ; Pourjavadi, Ali ; Zolfigol, Mohammad Ali ; Bamoniri, Abdolhamid

Abstract

A combination of silica chloride and wet SiO2 was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives under mild and heterogeneous condition

Earthquake Branch

, M.Sc. Thesis Sharif University of Technology Bagher Shemirani, Ali Reza (Author) ; Bakhshi, Ali (Supervisor)

Abstract

In the past few decades, shaking tables are widely used to evaluate system response of structures under seismic excitations. These devices are used without any fundamental research performed on a shaking table system as an entity model. In most of these studies for simplicity, it is assumed that there exist no considerable vibration and displacement around the shaking tables, and no attention is paid to the peripheral substances such as soil settled under the foundation.
In this thesis, result of ambient vibration test on shaking table system (solid deck, concrete foundation and soil layer) has been presented. Precise sensors known as low frequency and high accuracy accelerometers have...

Selective synthesis of conjugated enynes from α-arylalkynols using LiCl-Acidic Al2O3 under solvent-free conditions [electronic resource]

, Article Journal of Chemical Research ; Volume 2002, Number 8, 1 August 2002, pp. 378-380(3) Pourjavadi, A. (Ali) ; Bagheri Marandi, Gholam

Abstract

Free Content Selective synthesis of conjugated enynes from α-arylalkynols using LiCl-Acidic Al2O3 under solvent-free conditions

Selective preparation of fluorescent 1,8-naphthalimides using acidic alumina under microwave irradiation [electronic resource]

, Article Journal of Chemical Research ; 01/2001; 2001(11):485-487 Pourjavadi, A. (Ali) ; Bagheri Marandi, Gholam

Abstract

7H-benzimidazo[2,1-a]benz[de]isoquinolin-7-one compounds were prepared in a selective manner by reaction between o-phenylenediamines and appropriate 1,8-naphthalenedicarboxylic anhydrides using acidic alumina under microwave irradiation

Comparison between Performance of Stone Columns and RAPs from the Bearing Capacity and Settlement Reduction Viewpoints

, M.Sc. Thesis Sharif University of Technology Golestani Dariani, Ali Akbar (Author) ; Pak, Ali (Supervisor)

Abstract

Out of several ground improvement techniques available, stone columns have been widely used. This technique has been successfully applied to increase the bearing capacity and to reduce the settlement for foundation of structures like liquid storage tanks, earthen embankments, raft foundations, etc., where a relatively large settlement is permissible. This technique has, generally, been proven successful in increasing the stiffness of weak soils, upgrading their safe bearing capacity, and reducing their total and differential settlements, as well as speeding up their consolidation process. The beneficial effects of stone column installation in weak deposits is manifested in the form of...

Performance of Partially Filled Mini-Channels with Porous Media

, M.Sc. Thesis Sharif University of Technology Azimi, Adel (Author) ; Nouri, Ali (Supervisor) ; Moosavi, Ali (Co-Advisor)

Abstract

Laminar forced convection flow through a channel partially filled with a porous material was numerically studied in this thesis. The Navier-Stokes and Brinkman-Forchheimer equations were used to model the fluid flow in the free and porous regions, respectively. Coupling of the pressure and velocity fields was resolved using the SIMPLEC algorithm. The local thermal equilibrium was adopted in the energy equation. The effects of the thermal conductivity ratio, Darcy number, porosity, Reynolds number and height of the porous insert on velocity and temperature field were investigated. The results show that the flow behavior and its associated heat transfer are susceptible to the variation of the...

Improvement of Stability of Haptic Force Interaction with Virtual Environments Using a Haptic Interface with a Separate Tracker

, M.Sc. Thesis Sharif University of Technology Mashayekhi, Ahmad (Author) ; Meghdari, Ali (Supervisor) ; Nahvi, Ali (Supervisor)

Abstract

In the present study, a new version of haptic devices is presented in which user’s hand is in contact with the device just while collision with virtual surface. In this system, the position of user’s finger can be traced by using a camera and the haptic device follows user’s finger at the distance of about two centimeters. While the haptic device approaches to the virtual surface, gradually reduces its speed and stops about two centimeters distant of virtual plane. Then user’s hand collides with the haptic device which is static. Greater fidelity, transparency, more stability and also no need to large actuators are of the advantages of this system. In this project, first we present a new...

Simulation of the Biomolecule Imaging and Manipulation Via AFM by Molecular Dynamics Method

, M.Sc. Thesis Sharif University of Technology Kheiroddin, Mohsen (Author) ; Meghdari, Ali (Supervisor) ; Moosavi, Ali (Supervisor)

Abstract

In this thesis we try to find optimized parameters for imaging and manipulation of a biosample with AFM. For this we have prepared a numerous Molecular Dynamics simulation and find some reliable result. So, first we have focused on imaging process in Non contact mode (the less harmful mode). Then we headed into the manipulation process. The main problem about manipulating a biosample is the environment. In imaging section, the process of imaging a biomolecule by AFM is modeled using molecular dynamics simulations. Since the large normal force exerted by the tip on the biosample in contact and tapping modes may damage the sample structure and produce irreversible deformation, the non-contact...

Characterzing Variation of Small Strain Shear Modulus of Unsaturated Sand During Hydraulic Hysteresis with Bender Elements

, M.Sc. Thesis Sharif University of Technology Shahbazan, Parisa (Author) ; Pak, Ali (Supervisor) ; Khosravi, Ali (Supervisor)

Abstract

Results of previous studies on silt and clay indicated that variations in the small strain shear modulus, Gmax, during drying had a non-linear increasing trend with matric suction with greater values upon wetting. However, due to different material properties and inter-particle forces, different behaviour in Gmax is expected for sand. Although considerable research has been devoted in recent years to characterize the behaviour of Gmax of sand during drying, rather less attention has been paid to the effect of hydraulic hysteresis on Gmax and its variations during wetting. In the study presented herein, an effort was made to characterize the variation of Gmax for specimens of sand during...