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digital-controllers
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Five-leg converter topology for wind energy conversion system with doubly fed induction generator
, Article Renewable Energy ; Volume 36, Issue 11 , 2011 , Pages 3187-3194 ; 09601481 (ISSN) ; Poure, P ; Saadate, S ; Zolghadri, M. R ; Sharif University of Technology
Abstract
In this paper, application of a five-leg converter in Doubly Fed Induction Generator (DFIG) for Wind Energy Conversion Systems (WECS) is investigated. The five-leg structure and its PWM control are studied and performances are compared with the classical six-leg topology. The main drawback of five-leg converter with respect to the six-leg back-to-back converter is the need to increase the dc-link voltage for the same operation point, i.e. the same powers in case of WECS. So, different methods for the reduction of the required dc-link voltage in the five-leg case are studied. The five-leg converter is used to replace the conventional six-leg one, with the same ability. For the performance...
, M.Sc. Thesis Sharif University of Technology ; Sharif Khani, Mohammad (Supervisor)
Abstract
With the advancement of the technology, Design of low power devices such as biomedical systems, wireless sensor network, portable devices and … has received more attention. Digitally controlled oscillator (DCO) is one of the sub-blocks in systems such as all digital phase locked loop (ADPLL) which consumes the major power of the system. Therefore, Design of a low power DCO will decrease the power consumption of the system significantly.
In this thesis, a digital control oscillator which is ultra low power is design for system on chip applications. Coarse-Fine architecture is used with binary weighted cells in this design. For the Coarse tuning stage, a new delay cell is proposed which...
In this thesis, a digital control oscillator which is ultra low power is design for system on chip applications. Coarse-Fine architecture is used with binary weighted cells in this design. For the Coarse tuning stage, a new delay cell is proposed which...
Design and Manufacturing of a Propulsion Engine Thrust Forces Digital Test Stand in 3-DOF
, M.Sc. Thesis Sharif University of Technology ; Ghorbanian, Kaveh (Supervisor) ; Saeedi, Mohammad Hassan (Supervisor) ; Mozaffari, Ali Asghar (Supervisor)
Abstract
Measurements of magnitude and direction of thrust generated by a propulsion engine is important for verification of design, fabrication, assembely and or repare procedure used for a engine. Due to possible simplification in design calculations, human and machine errors in manufacturing process, the resulted thrust generated may be different from those values expected. Also, It is important to determine the dependency of magnitude and direction of thrust forces relative to tolerances and manufacturing processes. It is necessary to have thrust measuring stand with high accuracy with capability to measure the forces in different directions. A new digital engine test stand has been designed,...
Open-and short-circuit switch fault diagnosis for nonisolated DC-DC converters using field programmable gate array
, Article IEEE Transactions on Industrial Electronics ; Volume 60, Issue 9 , October , 2013 , Pages 4136-4146 ; 02780046 (ISSN) ; Jamshidpour, E ; Poure, P ; Saadate, S ; Zolghadri, M. R ; Sharif University of Technology
2013
Abstract
Fault detection (FD) in power electronic converters is necessary in embedded and safety critical applications to prevent further damage. Fast FD is a mandatory step in order to make a suitable response to a fault in one of the semiconductor devices. The aim of this study is to present a fast yet robust method for fault diagnosis in nonisolated dc-dc converters. FD is based on time and current criteria which observe the slope of the inductor current over the time. It is realized by using a hybrid structure via coordinated operation of two FD subsystems that work in parallel. No additional sensors, which increase system cost and reduce reliability, are required for this detection method. For...
A high power high voltage short pulse width pulse generator using direct drive method in application of modulating-cathode tubes drive
, Article IEEE International Symposium on Industrial Electronics, 5 July 2009 through 8 July 2009 ; 2009 , Pages 2097-2102 ; 9781424443499 (ISBN) ; Sadriyeh, S. M. R ; Mohammadi, A ; Maghsoudlou, B ; Mokhtari, H ; Alizadeh, H. R ; Shams Mousavi, S. M ; Sharif University of Technology
Abstract
The power supply of microwave tubes has high voltage and the possibility of produce high power pulse, which called in modulator. In this work, the results of design, construction and characterization of a direct drive pulse modulator for driving high power short pulse-width magnetron are reported. The sub-assemblies of modulator are; a primary high voltage supply, a switch bank with drivers and snubber circuits, a filament circuit, a digital control circuit with sensors and finally a pulse transformer. This paper is concerned with introduction and presentation of experimental evaluation of a new drive method for high power high voltage modulating-cathode microwave tubes. ©2009 IEEE
A fully linear 5.2 GHz - 5.8 GHz digitally controlled oscillator in 65-nm CMOS technology
, Article Microelectronics Journal ; Volume 90 , 2019 , Pages 48-57 ; 00262692 (ISSN) ; Torkzadeh, P ; Sadughi, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
A low-power fully linear integrated CMOS LC-based Digitally Controlled Oscillator is presented. The DCO operates in 5.2 GHz to 5.8 GHz range for using in IEEE 802.11a wireless applications. The system has been designed using 65 nm CMOS technology and 1.2 V supply voltage. By applying a proposed filter in DCO architecture −133.41 dBc/Hz phase noise at 1 MHz offset frequency from the fundamental carrier is achieved. The code generator and digital to analog converter designed to provide the high precision voltage required for fine-tuning. The output frequency swept through 10 control bits with 100 KHz resolution. The measured RMS jitter (∑ [1 KHz – 2 GHz]) from 5.8 GHz carrier is 1.65 fs. The...
Design of Low Phase Noise DCO in All Digital Frequency Synthesizers
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor)
Abstract
A new class of design has been introduced in the RF circuits and Frequency Synthesizers, which is based on the digital circuits. Implementation of the digital synthesizers suppresses the need to use loop filter and thus reduces the loop lock time. In this thesis different topologies of digitally controlled oscillators using inductor and capacitor tank and all digital architectures used in high frequency all digital synthesizers in 0.18um CMOS technology has been inspected and simulated. Novel techniques introduced to improve the ring oscillator-based design’s specifications which doesn’t need inductor. Using the introduced techniques, the phase noise has been lessened acceptably with respect...
Robust fault tolerant explicit model predictive control
, Article Automatica ; Volume 97 , 2018 , Pages 248-253 ; 00051098 (ISSN) ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this study, a new algorithm for explicit model predictive control of linear discrete-time systems subject to linear constraints, disturbances, uncertainties, and actuator faults is developed. The algorithm is based on dynamic programming, constraint rearrangement, multi-parametric programming, and a solution combination procedure. First of all, the dynamic programming is used to recast the problem as a multi-stage optimization problem. Afterwards, the constraints are rearranged in an innovative manner to take into account the worst admissible situation of unknown bounded disturbances, uncertainties, and actuator faults. Then, the explicit solution of the reformulated optimization problem...
Design and implementation of a stable platform digital controller based on DSP
, Article ICSES 2008 International Conference on Signals and Electronic Systems, ICSES'08, Krakow, 14 September 2008 through 17 September 2008 ; 2008 , Pages 453-456 ; 9788388309526 (ISBN) ; Chamani Takaldani, H. R ; Moosavienia, A ; Monfaredi, K ; Ebrahimi Atani, R ; Sharif University of Technology
2008
Abstract
The principle, configuration, and the special features of a stable platform digital controller are presented in this paper. The main goal of this paper is replacing an analog controller with its awaiting digital one. This has been done using TMS320LF2402 digital signal processor which offers the enhanced TMS320 DSP architectural design of the C2xx core CPU for low-cost, low-power, and high-performance processing capabilities. The experimental results show that the digital controller is identical to the analog one and can be a suitable replacement for the analog controller. Copyright © 2008 by Department of Electronics, AGH University of Science and Technology
A nonlinear model predictive controller design for Sheppard-Taylor based PFC rectifier
, Article IECON Proceedings (Industrial Electronics Conference), 3 November 2009 through 5 November 2009 ; 2009 , Pages 1403-1408 ; Tahami, F ; Sharif University of Technology
Abstract
This paper addresses a nonlinear model predictive controller design for a single-phase PFC rectifier exploiting the Sheppard-Taylor converter. After approximation of the tracking error in the receding horizon by its Taylor-series expansion to any specified order, an analytic solution to the MPC is developed and a closed-form nonlinear predictive controller is introduced. The proposed nonlinear model predictive control (NMPC) derived using approximation can stabilize the original nonlinear systems if certain conditions, which can be met by properly choosing predictive times and the order for Taylor expansion, are satisfied. The main advantage of this digital control method is that unity power...
Analysis and design of predictive control strategy for sheppard-taylor based PFC rectifier
, Article 2008 IEEE International Symposium on Industrial Electronics, ISIE 2008, Cambridge, 30 June 2008 through 2 July 2008 ; 2008 , Pages 397-402 ; 1424416655 (ISBN); 9781424416653 (ISBN) ; Tahami, F ; Sharif University of Technology
2008
Abstract
In this paper CCM/CVM operation and modeling of the Sheppard-Taylor topology is reviewed and a predictive control strategy is applied for a Sheppard-Taylor-based power factor correction (PFC) rectifier. Compared to conventional boost or buck - boost PFC's, this topology allows a better current tracking at the AC side, with a relatively reduced voltage at the DC side. Consequently, the high frequency AC filters required by the buck PECs are avoided, and the voltage stresses on the boost switches are significantly reduced. Furthermore In predictive control strategy the duty cycle required to achieve unity power factor in a half line period can be calculated in advance. The main advantage of...
Optimum nonlinear model predictive controller design for flyback PFC rectifiers
, Article ISIEA 2010 - 2010 IEEE Symposium on Industrial Electronics and Applications, 3 October 2010 through 5 October 2010 ; October , 2010 , Pages 70-75 ; 9781424476473 (ISBN) ; Abedi, M. R ; Rezaei, K ; IEEE Malaysia Section; IEEE Malaysia Power Electron. (PEL)/; Ind. Electron.(IE)/ Ind. Appl. (IA) Jt. Chapter ; Sharif University of Technology
2010
Abstract
Single-phase ac-dc Power Factor Correction (PFC) rectifiers have attracted considerable attention in recent years due to the adoption of increasingly stringent power quality regulations. In this paper a nonlinear model predictive controller design for a single-phase Flyback PFC rectifier is presented. After approximation of the tracking error in the receding horizon by its Taylor-series expansion to a specified order, an analytic solution to the model predictive control (MPC) is developed and a closed-loop nonlinear predictive controller is introduced. The main advantage of this digital control method is that unity power factor can be achieved over wide input voltage, load current range and...
FPGA-based reconfigurable control for fault-tolerant back-to-back converter without redundancy
, Article IEEE Transactions on Industrial Electronics ; Volume 60, Issue 8 , May , 2013 , Pages 3360-3371 ; 02780046 (ISSN) ; Poure, P ; Saadate, S ; Zolghadri, M. R ; Sharif University of Technology
2013
Abstract
In this paper, an FPGA-based fault-tolerant back-to-back converter without redundancy is studied. Before fault occurrence, the fault-tolerant converter operates like a conventional back-to-back six-leg converter, and after the fault, it becomes a five-leg converter. Design, implementation, and experimental verification of an FPGA-based reconfigurable control strategy for this converter are discussed. This reconfigurable control strategy allows the continuous operation of the converter with minimum affection from a fault in one of the semiconductor switches. A very fast detection scheme is used to detect and locate the fault. Implementation of the fault detection and of the fully digital...
Intelligent control of chaos using linear feedback controller and neural network identifier
, Article Communications in Nonlinear Science and Numerical Simulation ; Volume 17, Issue 12 , 2012 , Pages 4731-4739 ; 10075704 (ISSN) ; Khodabakhsh, M ; Salarieh, H ; Sharif University of Technology
2012
Abstract
A method for controlling chaos when the mathematical model of the system is unknown is presented in this paper. The controller is designed by the pole placement algorithm which provides a linear feedback control method. For calculating the feedback gain, a neural network is used for identification of the system from which the Jacobian of the system in its fixed point can be approximated. The weights of the neural network are adjusted online by the gradient descent algorithm in which the difference between the system output and the network output is considered as the error to be decreased. The method is applied on both discrete-time and continuous-time systems. For continuous-time systems,...
Fast detection of open-switch faults with reduced sensor count for a fault-tolerant three-phase converter
, Article 2011 2nd Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2011 ; 2011 , Pages 546-550 ; 9781612844213 (ISBN) ; Zolghadri, M ; Poure, P ; Saadate, S ; Sharif University of Technology
Abstract
Fast fault detection and reconfiguration is necessary in power electronic converters in lots of applications to prevent further damage and to make possible the continuity of service. In this paper a very fast fault detection scheme is presented that minimizes the use of voltage sensors. A fault tolerant topology is studied. Control and fault detection system are implemented on a single FPGA and hardware in the loop experiments are performed to evaluate the detection scheme, the digital controller and the structure
Output feedback adaptive control of a class of nonlinear discrete-time systems with unknown control directions and preceded by hysteresis
, Article International Journal of Control ; Volume 88, Issue 11 , Jun , 2015 , Pages 2412-2422 ; 00207179 (ISSN) ; Ghaderi, A ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
This paper considers the output feedback adaptive controller design problem for a class of discrete-time nonlinear systems in output feedback form with unknown control directions and preceded by unknown hysteresis. The problem of lacking in a-priori knowledge on the control directions and unknown hysteresis are solved by using the discrete Nussbaum gain and Prandtl-Ishlinskii model, respectively. The system is transformed into the form of a nonlinear auto regressive moving average (NARMA) model to construct an output feedback control. To overcome the noncausal problem in the control design, future output prediction laws and parameter update laws with the dead-zone technique are constructed...
Model predictive control of non-linear discrete time systems: A linear matrix inequality approach
, Article IET Control Theory and Applications ; Volume 4, Issue 10 , October , 2010 , Pages 1922-1932 ; 17518644 (ISSN) ; Taghirad, H. D ; Haeri, M ; Sharif University of Technology
2010
Abstract
Using a non-linear model in model predictive control (MPC) changes the control problem from a convex quadratic programme to a non-convex non-linear problem, which is much more challenging to solve. In this study, we introduce an MPC algorithm for non-linear discrete-time systems. The systems are composed of a linear constant part perturbed by an additive state-dependent non-linear term. The control objective is to design a state-feedback control law that minimises an infinite horizon cost function within the framework of linear matrix inequalities. In particular, it is shown that the solution of the optimisation problem can stabilise the non-linear plants. Three extensions, namely,...
General Characterization Method and a Fast Load-Charge-Preserving Switching Procedure for the Stepwise Adiabatic Circuits
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 63, Issue 1 , 2016 , Pages 80-90 ; 15498328 (ISSN) ; Sharifkhani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
An analytical method is presented to characterize stepwise adiabatic circuits (SACs). In this method, the SACs are modeled as a discrete time system. Unlike previous methods, the stability is verified for arbitrary load capacitor ratios. Moreover, this method presents analytical derivations to offer an area/energy efficient design methodology. MATLAB simulations, post-layout simulations in the CMOS 0.18 μm technology, silicon measurements, and measurements based on discrete components confirm the precision of the analytical derivations. Using the proposed design methodology, a capacitive tank has been designed which reduces the energy consumption by 20% while the total size of the tank...
Model predictive control of nonlinear discrete time systems with guaranteed stability
, Article Asian Journal of Control ; 2018 ; 15618625 (ISSN) ; Haeri, M ; Sharif University of Technology
Wiley-Blackwell
2018
Abstract
This paper presents the design of a new robust model predictive control algorithm for nonlinear systems represented by a linear model with unstructured uncertainty. The linear model is obtained by linearizing the nonlinear system at an operating point and the difference between the nonlinear and linear model is considered as a Lipschitz nonlinear function. The controller is designed for the linear model, which fulfills the stabilization condition for the nonlinear term. Unlike previous studies that have not considered a valid Lipschitz matrix of nonlinear term in the design process, we propose an algorithm in this paper in which it is considered. Therefore, the closed loop stability of the...
Model predictive control of nonlinear discrete time systems with guaranteed stability
, Article Asian Journal of Control ; Volume 22, Issue 2 , 2020 , Pages 657-666 ; Haeri, M ; Sharif University of Technology
Wiley-Blackwell
2020
Abstract
This paper presents the design of a new robust model predictive control algorithm for nonlinear systems represented by a linear model with unstructured uncertainty. The linear model is obtained by linearizing the nonlinear system at an operating point and the difference between the nonlinear and linear model is considered as a Lipschitz nonlinear function. The controller is designed for the linear model, which fulfills the stabilization condition for the nonlinear term. Unlike previous studies that have not considered a valid Lipschitz matrix of nonlinear term in the design process, we propose an algorithm in this paper in which it is considered. Therefore, the closed loop stability of the...