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permanent-magnets
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Utilization of Airborne Wind Energy in Iran
, M.Sc. Thesis Sharif University of Technology ; Vesaghi, Mohammad Ali (Supervisor) ; Soltani, Mohammad Reza (Supervisor)
Abstract
A Flying Electric Generator (FEG) can be a wind turbine which operates at high altitudes, where there is a continuous fast flow of air and converts wind energy to electrical power.The related field is an interdisciplinary area and is mostly related to the Aerospace Engineering and Energy Conversion. We focused on Iran, as one of the few lands in the northern hemisphere that has a high overall amount of high altitude wind energy for at least half of the year over it, according to the information of atlas of airborne wind energy in this work.So to install the FEGs in Iran, we had to find, places with a safe aerial space overhead which grant us reliable spots over country. These places found by...
Low Cost Sensor-Less Control of Permanent Magnet Synchronous Motor for Home Appliances
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Proper operation of a permanent magnet synchronous motor (PMSM) requires rotor position information. Commonly a rotor position sensor, such as optical encoder or resolver, is used for this purpose. These sensors add cost, weight and degrade reliability of the drive system. Using position and speed sensors for control of PMSM’s in home appliances is not cost effective. In this thesis, a novel method for predicting position of the rotor and winding inductance of the permanent magnet synchronous machine has been presented. In this method, machine anisotropy is utilized for rotor position estimation purposes like what in the high frequency injection techniques. Each leg of the PWM inverter...
Proposal of a Modular Structure and a Load Sharing Strategy among Back to Back Converters for Wind Turbines
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
The utilization of wind power has been increasing in recent years which lead to enhance the the usage of wind power capacity in the range of MegaWatt. However, due to the limitation ofswitching devices capacity, which exists in power electronic converters, improving the capacity of wind power generation is not accessible. Thus, a feasible solution for this problem is paralleling power electronics converters, which increases both the capacity of power generation and the reliability of wind turbine systems. Nevertheless, paralleling converters may cause a circulating-current which brings current discrepancy, current waveform distortion, power losses, increase in THD of currents, and reduction...
Transient error compensation in sensorless control of PMSM
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 38-43 ; 9781467301114 (ISBN) ; Tahami, F ; Sharif University of Technology
2012
Abstract
Sensorless schemes based on HF carrier injection are capable of estimating rotor position in a wide speed range. In these schemes first an additional HF voltage is injected to stator windings. The corresponding HF current is decoupled from main stator currents and the position of the rotor saliency is estimated based on the decoupled HF current in a closed loop tracking observer. The tracking observer is capable of tracking rotor saliency with no steady state error. Transient error appears when the motor starts to move or whenever the rotor speed changes because of any disturbance or any change in the rotor speed command. In this paper a new solution is proposed in order to compensate for...
Three-phase PFC rectifier with high efficiency and low cost for small PM synchronous wind generators
, Article 7th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2016, 16 February 2016 through 18 February 2016 ; 2016 , Pages 302-307 ; 9781509003754 (ISBN) ; Tahami, F ; Valipour, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Small Permanent Magnet Synchronous Generators (PMSG's) are widely used in low power wind turbines. In order to inject the electrical power, generated by PMSG, to the grid, a back-To-back AC/AC power electronic converter is required. In this paper, a novel low cost efficient AC/DC converter is proposed for rectifier stage to obtain the maximum power per ampere of PMSG by using Power Factor Correction method. The new structure is based on DCM SEPIC converter. Reducing the number of semi-conductor switches has decreased converter cost. Additionally, other advantages of this Converter are employing easy control method to obtain the maximum power per ampere and using Synchronous inductance of...
The select of a permanent magnet brushed DC motor with optimal controller for providing propellant of @home mobile robot
, Article 2010 IEEE International Conference on Mechatronics and Automation, ICMA 2010, 4 August 2010 through 7 August 2010 ; August , 2010 , Pages 1137-1141 ; 9781424451418 (ISBN) ; Khosroshahi, M ; Abbasi, M ; Ghaemi Osgouie, K ; Sharif University of Technology
2010
Abstract
This paper first will describe @Home Mobile Robot and DC motors. In continuous, is designed a Direct current (DC) motor for special task due to specific speed diagram for considered robot. This robot wants to work in intermittent operation condition. Finally is done a speed control on a selected permanent magnet brushed DC motor using of Linear-Quadratic-Regulator (LQR), Linear-Quadratic-Gaussian (LQG) and Fuzzy logic controllers
Theoretical and experimental studies of a magnetically actuated valveless micropump
, Article Journal of Micromechanics and Microengineering ; Volume 27, Issue 1 , 2017 ; 09601317 (ISSN) ; Shafii, M. B ; Moosavi, A ; Sharif University of Technology
Institute of Physics Publishing
2017
Abstract
This paper presents the prototype design, fabrication, and characterization of a magnetically actuated micropump. The pump body consists of three nozzle/diffuser elements and two pumping chambers connected to the ends of a flat-wall pumping cylinder. A cylindrical permanent magnet placed inside the pumping cylinder acts as a piston which reciprocates by using an external magnetic actuator driven by a motor. The magnetic piston is covered by a ferrofluid to provide self-sealing capability. A prototype composed of three bonded layers of polymethyl-methacrylate (PMMA) has been fabricated. Water has been successfully pumped at pressures of up to 750 Pa and flow rates of up to 700 μl min-1 while...
Stand alone performance of permanent magnet synchronous wind power generator with current source matrix converter
, Article Electric Power Components and Systems ; Volume 43, Issue 8-10 , 2015 , Pages 1018-1027 ; 15325008 (ISSN) ; Mokhtari, H ; Chang, L ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
A matrix converter is a voltage/current source AC/AC frequency converter. In grid-connected operation of a variable-speed permanent magnet synchronous wind power generator, the matrix converter is normally controlled as a voltage source converter. In this control method, the generator-side voltage is synthesized from the grid-side voltage source. However, in the stand-alone mode of operation, the grid-side stiff voltage source is not available, and the input filter of the matrix converter is unstable. In this article, a new control method is presented that controls a permanent magnet synchronous wind generator in a stand-alone mode with a matrix converter as a current source converter. The...
Simulation and experimental study of real-time robust control of hybrid stepper motor with QFT method in micro-step operation
, Article Proceedings of the IEEE International Conference on Mechatronics 2004, ICM'04, Istanbul, 3 June 2004 through 5 June 2004 ; 2004 , Pages 364-368 ; 0780385993 (ISBN) ; Vossoughi, G. R ; Sharif University of Technology
2004
Abstract
Real-time linear robust control of a two phase hybrid stepper motor with Quantitative Feedback Theory method in micro-stepping operation is considered in this paper. Utilizing the phase currents as inputs, linear robust controller is derived for a Hybrid Stepper Motor that achieves robustness to parametric and dynamic uncertainties such as viscous friction, load torque, flux linkage and other uncertainties. Simulation and experimental studies are presented to show the efficiency of the control design approach
Sensorless control of PMSMs with tolerance for delays and stator resistance uncertainties
, Article IEEE Transactions on Power Electronics ; Volume 28, Issue 3 , 2013 , Pages 1391-1399 ; 08858993 (ISSN) ; Tahami, F ; Sharif University of Technology
2013
Abstract
Position sensorless control of ac machines at zero and low speed is possible using high-frequency carrier injection methods. These methods utilize anisotropic properties of rotor. Therefore, they may lose their efficiency for nonsalient machines or machines with small rotor saliency. In these machines, measurement noise and offset, existing delays, as well as model uncertainties may lead to inaccurate estimation of rotor position. Stator resistance which is usually neglected in these methods may also lead to a considerable error especially in machines with small rotor saliency. In this paper, a new position estimation method is presented, and it is shown that in comparison to conventional...
Sensorless control of non-salient PMSM using simultaneous injection of two HF signals
, Article Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC ; March , 2014 , p. 2463-2468 ; Yaghoubi, M ; Tahami, F ; Bakhshai, A ; Jain, P. K ; Sharif University of Technology
Abstract
In recent years sensorless techniques based on HF carrier injection have become very popular as they are capable to estimate rotor position in a wide speed range. They can provide precise control over interior PMSMs without the accompanying need for a position sensor. However, in surface-mounted PMSMs, the estimation of rotor position is only reliable at light loads due to the very small saliency arising from main flux saturation. The anisotropy caused by stator flux saturation is not necessarily in alignment with rotor position especially at heavy loads. In this paper a novel solution is proposed to make use of the sensorless scheme in a surface-mounted PMSM even at heavy loads
Sensorless control of non-salient PMSM using asymmetric alternating carrier injection
, Article 2011 IEEE Symposium on Industrial Electronics and Applications, ISIEA 2011, 25 September 2011 through 28 September 2011 ; September , 2011 , Pages 7-12 ; 9781457714184 (ISBN) ; Tahami, F ; Sharif University of Technology
Abstract
Sensorless control of permanent magnet synchronous motors allows reducing cost and complexity, and increasing mechanical robustness and noise immunity. Sensorless methods based on high frequency carrier injection have attracted considerable attention in recent years as they can estimate rotor position in a wide speed range. These methods employ anisotropic properties of rotor to estimate rotor position in ac machines. With internal permanent magnet motors, the high frequency signal injection method can deliver precise sensorless control, however in surface-mounted permanent magnet machines, where a small saliency arises from main flux saturation, the estimation of rotor magnet position is...
Sensor fault-tolerant scheme for IPM synchronous motor drives via nonlinear observer
, Article AUPEC'09 - 19th Australasian Universities Power Engineering Conference: Sustainable Energy Technologies and Systems, 27 September 2009 through 30 September 2009, Adelaide ; 2009 ; 9780863967184 (ISBN) ; Farshidnia, A ; Keivanian, R ; Sharif University of Technology
Abstract
This paper describes a control scheme that allows an IPMS motor drive system to operate in the event of current and speed sensor faults. This task can be achieved by two control strategies: a nominal performance controller and a fault detection part. The nominal controller combines field oriented control and addresses fault tolerance scheme. Fault-tolerant strategy will operate in parallel with the system until a fault is detected. This approach is based on the adaptive backstepping observer. Stator resistance as possible source of system uncertainty is taken into account under different operating conditions. Sensors failure are detected and developed observer is used to estimate currents...
Robust independent and simultaneous position control of multiple magnetic microrobots by sliding mode controller
, Article Mechatronics ; Volume 84 , 2022 ; 09574158 (ISSN) ; Yousefi, M ; Nejat Pishkenari, H ; Vossoughi, G ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Recent development in technology and improvement of manufacturing tools have accelerated the use of microrobots (MRs) in numerous areas such as micro sensing and medical applications. The ability to control multiple MRs simultaneously and independently could lead to higher performance, and even make new applications possible. In this paper, we have proposed a system for simultaneous and independent control of the position of multiple MRs in a plane. The system consists of 2N permanent magnets (PMs) with a circular arrangement in the plane around the workspace and a pair of Helmholtz coil to control N MRs. PMs are rotated by servomotors, and the coil aligns the orientation of the MRs normal...
Resonance frequencies and stability of two flexible permanent magnetic beams facing each other
, Article Journal of Sound and Vibration ; Volume 331, Issue 26 , 2012 , Pages 5745-5754 ; 0022460X (ISSN) ; Mohammadkhani, H ; Sharif University of Technology
2012
Abstract
This paper aims at investigating the interaction of two flexible permanent magnet beams facing each other. The governing equations of motion are obtained based on the Euler-Bernoulli beam model along with Hamiltons principle. Assuming that the beams tips are far enough, each magnet beam is considered as a series of dipole segments and the external force and moment distributions over each beam due to the magnetic field of the other one is calculated in the deformed configuration. The transverse deflections of the beams are written as series expansions of the mode shapes of an unloaded cantilever beam and the Galerkin method is applied to determine the stability and resonance frequencies....
Reactive power control of permanent-magnet synchronous wind generator with matrix converter
, Article IEEE Transactions on Power Delivery ; Volume 28, Issue 2 , 2013 , Pages 575-584 ; 08858977 (ISSN) ; Mokhtari, H ; Chang, L ; Sharif University of Technology
2013
Abstract
In this paper, the reactive power control of a variable-speed permanent-magnet synchronous wind generator with a matrix converter at the grid side is improved. A generalized modulation technique based on singular value decomposition of the modulation matrix is used to model different modulation techniques and investigate their corresponding input reactive power capability. Based on this modulation technique, a new control method is proposed for the matrix converter which uses active and reactive parts of the generator current to increase the control capability of the grid-side reactive current compared to conventional modulation methods. A new control structure is also proposed which can...
Production of (Nd,MM)2(Fe,Co,Ni)14B-type sintered magnets using a binary powder blending technique
, Article Journal of Alloys and Compounds, Lausanne ; Volume 298, Issue 1-2 , 2000 , Pages 319-323 ; 09258388 (ISSN) ; Kianvash, A ; Seyyed Reihani, M ; Yoozbashi Zadeh, H ; Sharif University of Technology
Elsevier Science S.A
2000
Abstract
The anisotropic (Nd,MM)2(Fe,Co,Ni)14B-type magnets were produced using the binary alloy sintering method (MM denotes a Misch-metal). The composition of the master alloy was close to stoichiometric Nd2Fe14B compound, while that of the sintering aid was MM38.2Co46.4Ni15.4. The microstructures of sintered magnets were investigated using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray detector (EDX). X-ray diffractometry (XRD) was also employed for phase analysis. The optimum magnetic properties were obtained for a composition of Nd11.9MM2.9Fe73.9Co3.3Ni1.1B6.9 made of 90 wt.% master alloy and 10 wt.% sintering aid. The two main phases, i.e. the (RE)2(TM)14B phase...
Prediction of chaos in non-salient permanent-magnet synchronous machines
, Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 377, Issue 1-2 , December , 2012 , Pages 73-79 ; 03759601 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
2012
Abstract
This Letter tries to find the area in parameter space of a non-salient Permanent-Magnet Synchronous Machine (PMSM) in which chaos can occur. This area is briefly named as chaotic area. The predicted chaotic area is obtained by checking some conditions which are necessary for existence of chaos in a dynamical system. In this Letter, it is assumed that this machine is in the generator mode, and its model is based on direct and quadrature axis of stator voltages and currents. The information of the predicted area is used in non-chaotic maximum power control of torque in the machine
Performance verification of saturated IPM bearingless motors considering magnetic pull variation
, Article Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016, 25 September 2016 through 28 September 2016 ; 2016 , Pages 643-649 ; 9781509017980 (ISBN) ; Nasiri Gheidari, Z ; Rahman, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Interior permanent magnet (IPM) bearingless motors are becoming a good choice for high-speed applications. In these motors, reducing the thickness of the PM leads to the increase of the radial forces which affects the demagnetizing fields. Various types of PM motors have so far been recommended for enhancement of the radial forces and torque. In the proposed IPM motor the d-axis flux-linkage and the q-axis torque component are raised due to the armature reaction and this saturates the stator teeth. In addition, the magnetic attraction force generated by displacement force depends on the armature reaction. The mathematical model of IPM bearingless motor based on the dq transformation,...
Performance analysis of concentrated wound-rotor resolver for its applications in high pole number permanent magnet motors
, Article IEEE Sensors Journal ; Volume 17, Issue 23 , 2017 , Pages 7877-7885 ; 1530437X (ISSN) ; Nasiri Gheidari, Z ; Tootoonchian, F ; Oraee, H ; Sharif University of Technology
Abstract
High pole number permanent magnet (PM) motors, due to their high torque density, have been receiving considerable attentions in recent years. To achieve an accurate position control in PM machines, resolvers are suggested for industrial applications. Mechanical and electromagnetic considerations in the case of high pole number resolvers lead the machine designers to choose small cores with low slot numbers. This paper proposes two different on-tooth winding configurations to achieve high pole number without increasing the slot numbers, while the accuracy of the detected position is intended to be the maximum value. Variable turn on tooth winding (VTTW) is compared with fractional slot...