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    A control strategy for reducing the torque ripple in low speed operation of direct torque controlled induction motor

    , Article 2004 IEEE International Symposium on Industrial Electronics, IEEE-ISlE, 4 May 2004 through 7 May 2004 ; Volume 2 , 2004 , Pages 1203-1208 Kaboli, F. S ; Zolghadri, S. M. R ; Haghbin, T. S ; Homaifar, F. A ; Sharif University of Technology
    2004
    Abstract
    A new switching table is proposed for decreasing the torque ripple in DTC especially in low speed. Each sector is divided to two half sector and a proper vector set is defined for each. Through this new switching table, the torque response is smooth even in the beginning of each sector and it leads to the reduction of torque ripple. None of motor parameters are used in this switching strategy and there is no need to shorten the sampling period. Simulation and experimental results confirm the ability of this method in reducing the torque ripple. ©2004 IEEE  

    Torque ripple minimization in DTC of induction motor based on optimized flux value determination

    , Article The 29th Annual Conference of the IEEE Industrial Electronics Society, Roanoke, VA, 2 November 2003 through 6 November 2003 ; Volume 1 , 2003 , Pages 431-435 Kaboli, S ; Zolghadri, M. R ; Haghbin, S ; Emadi, A ; Sharif University of Technology
    2003
    Abstract
    Torque ripple is a major difficulty in direct torque controlled induction motors. The reference value of the motor flux greatly influences the torque ripple. On the other hand, many motors work in an operating cycle, which includes load intervals of less than their nominal power. In these situations, it is not necessary to set their flux value as the nominal value. In this paper, the effect of the reference value of the motor flux on the motor torque ripple is investigated. A new control algorithm is proposed to determine the reference value of the flux according to the value of the motor torque. Simulation and experimental results justify the validity of the proposed method to reduce the... 

    Effects of the flux value on the torque ripple of the direct torque controlled induction motor drives determination

    , Article 5th International Conference on Power Electronics and Drive Systems, PEDS 2003, 17 November 2003 through 20 November 2003 ; Volume 1 , 2003 , Pages 439-444 ; 0780378857 (ISBN) Kaboli, S ; Zolghadri, M. R ; Haghbin, S ; Homaifar, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2003
    Abstract
    Torque ripple is a major difficulty in direct torque control of induction motors. The reference value of the motor flux greatly influences the torque ripple. On the other hand, many motors work in an operating cycle, which includes load intervals of less than their nominal power. In these situations, it is not necessary to set their flux value as the nominal value. In this paper, the effect of the reference value of the motor flux on the motor torque ripple is investigated. The effect of the flux reference variation on the motor power factor as well as torque dynamics is also presented. Simulation results as well as experimental results justify the validity of the proposed method on the... 

    Online optimal flux controller for DTC based induction motor drives

    , Article IECON 2004 - 30th Annual Conference of IEEE Industrial Electronics Society, Busan, 2 November 2004 through 6 November 2004 ; Volume 2 , 2004 , Pages 1391-1395 Kaboli, S ; Zolghadri, M. R ; Roye, D ; Emadi, A ; Sharif University of Technology
    2004
    Abstract
    A flux search controller is proposed to achieve the best efficiency in a direct torque controlled induction motor with light load. The reference flux value is determined through a minimization algorithm with stator current as objective function. Experimental results show that using motor current instead of motor input power as the objective function causes better performance. © 2004 IEEE  

    A new definition for total harmonic distortion in inverter-fed induction motors including loss considerations

    , Article 42nd International Conference on Large High Voltage Electric Systems 2008, CIGRE 2008, Paris, 24 August 2008 through 29 August 2008 ; 2008 Fard, H. G ; Kaboli, S ; Oraee, H ; Sharif University of Technology
    2008
    Abstract
    Harmonic information is necessary tools in the estimation of motors life and performance. The conventional expression of harmonic amount is carried out by total Harmonic distortion. This distortion factor is only related to amplitude of harmonics while the motor loss is affected by frequency domain of them. In this paper a new definition of this factor has been presented. This definition includes the frequency of harmonics as well as their amplitudes. Experimental results verify the validity of this new definition  

    On the performance of optimal flux search controller for DTC based induction motor drives

    , Article 2005 IEEE International Conference on Electric Machines and Drives, San Antonio, TX, 15 May 2005 through 15 May 2005 ; 2005 , Pages 1752-1756 ; 0780389875 (ISBN); 9780780389878 (ISBN) Kaboli, S ; Vahdati Khajeh, E ; Zolghadri, M. R ; Homaifar, A ; Sharif University of Technology
    IEEE Computer Society  2005
    Abstract
    Application of a flux search controller in direct torque control of induction motor drives produces divergence problem and steady state flux ripple, because of the disturbance in the control loop. In this paper, an investigation about the origin of this noise has been performed. It is shown that the variation of voltage harmonics is the main reason of disturbance in the flux control loop. The minimum allowable value of flux step has been determined based on this analysis to prevent the divergence problem. Feasibility of noise cancellation has been discussed. Experimental results are presented to justify the theoretical analysis. © 2005 IEEE  

    A fast optimal flux search controller with improved steady state behavior for DTC based induction motor drives

    , Article 2005 IEEE International Conference on Electric Machines and Drives, San Antonio, TX, 15 May 2005 through 15 May 2005 ; 2005 , Pages 1732-1736 ; 0780389875 (ISBN); 9780780389878 (ISBN) Kaboli, S ; Vahdati Khajeh, E ; Zolghadri, M. R ; Homaifar, A ; Sharif University of Technology
    IEEE Computer Society  2005
    Abstract
    Flux search controllers are proposed to improve the efficiency of electrical motors especially induction motors. In this paper, a flux search controller is proposed to increase the efficiency of a direct torque controlled induction motor with light load. The reference flux value is determined through a two stage minimization algorithm with the amplitude of the stator current as the objective function. In the transient state, a great flux step is used to speed up the convergence. In the steady state, a noise cancellation algorithm is used to let using small flux step and improves the steady state behavior of flux controller. Simulation and experimental confirm the fast dynamics of the... 

    Flux search control of field oriented control of six-phase induction motor supplied by SVPWM

    , Article Przeglad Elektrotechniczny ; Volume 87, Issue 8 , 2011 , Pages 171-175 ; 00332097 (ISSN) Taheri, A ; Rahmati, A ; Kaboli, S ; Sharif University of Technology
    2011
    Abstract
    This paper deals with the efficiency optimization of Field Oriented Control (FOC) of a six-phase induction motor supplied by Space Vector PWM (SVPWM) using the flux Search Controller (SC) technique. The proposed technique is based on controlling flux to achieve maximum efficiency at light load or low speed. Flux search controller technique is not only cost effective and easy to implement but also robust against parameter variations. Flux control algorithm in six-phase induction machine speed controller reduces 6n±1 harmonic loss as well as other losses like that of copper and core. Simulation results are carried out and they verify the effectiveness of the proposed approach  

    Energy optimization of field oriented six-phase induction motor drive

    , Article Advances in Electrical and Computer Engineering ; Volume 11, Issue 2 , 2011 , Pages 107-112 ; 15827445 (ISSN) Taheri, A ; Rahmati, A ; Kaboli, S ; Sharif University of Technology
    2011
    Abstract
    This paper deals with the efficiency optimization of Field Oriented Control (FOC) of a six-Phase Induction Motor (6PIM) by adaptive flux search control. The six-phase induction motor is supplied by Space Vector PWM (SVPWM) and voltage source inverter. Adaptive flux search controller is fast than ordinary search control technique and easy to implement. Adaptive flux Search Control (SC) technique decreases the convergence time by proper change of flux variation steps and increases accuracy of the SC technique. A proper loss model of 6PIM in conjunction with the proposed method is used. The six-phase induction machine has large zero sequence harmonic currents that can be reduced by SVPWM... 

    A novel fault tolerant reconfigurable concept for vector control of induction motors

    , Article EPE-PEMC 2006: 12th International Power Electronics and Motion Control Conference, Portoroz, 30 August 2006 through 1 September 2006 ; 2007 , Pages 1199-1204 ; 1424401216 (ISBN); 9781424401215 (ISBN) Tahami, F ; Shojaei, A ; Sharif University of Technology
    2007
    Abstract
    AC drive users with sophisticated applications are demanding greater reliability to avoid process interruptions. AC motor drive systems are susceptible to sensors failure. A novel fault tolerant Field Oriented Control system for induction motors is introduced. The system maintains speed control in the event of sensors malfunction and adverse signal conditions, providing enhanced reliability. Different motor models are combined by a Fuzzy aggregation system in order to give a reliable estimate of flux vector. The proposed control system is an effective and easy to implement method giving a potential for motor drive reliability enhancement. © 2006 IEEE  

    A fast flux search controller for DTC-based induction motor drives

    , Article IEEE Transactions on Industrial Electronics ; Volume 54, Issue 5 , 2007 , Pages 2407-2416 ; 02780046 (ISSN) Kaboli, S ; Zolghadri, M. R ; Vahdati Khajeh, E ; Sharif University of Technology
    2007
    Abstract
    In this paper, a flux search controller is proposed to increase the efficiency of a direct torque-controlled induction motor in full load range. The value of the flux reference is determined through a minimization algorithm. The amplitude of stator current is used as the objective function since it is shown that samples of the stator current have better statistical properties than input power. In addition, the stator current has more sensitivity to the flux variation than input power. These two properties allow implementing an adaptive algorithm to determine the proper flux step without waste of time. The minimum allowable value of the flux step has been determined based on this process to... 

    Design and implementation of a predictive controller for reducing the torque ripple in direct torque control based high frequency induction motor drives

    , Article 2004 IEEE 35th Annual Power Electronics Specialists Conference, PESC04, Aachen, 20 June 2004 through 25 June 2004 ; Volume 2 , 2004 , Pages 1169-1174 ; 02759306 (ISSN) Kaboli, S ; Zolghadri, M. R ; Roye, D ; Guiraud, J ; Schanen, J. L ; Sharif University of Technology
    2004
    Abstract
    In Direct Torque Control, selection of each voltage vector is based on the measured parameters in the beginning of the sampling period. Due to the fast dynamic of torque, this delay causes an extra torque ripple. In this paper, a new predictive controller is proposed for compensating this delay and reducing the torque ripple. The stator current is measured in the beginning of each sampling period and its expected value in the end of period is predicted according to an extrapolation algorithm. This algorithm is performed by calculating the slope of stator current variation according to the stator flux variation. Thus, there is no need to solve the high order equations of machine. The... 

    Flux harmonic spectrum proccessing of direct torque controlled induction motor

    , Article Proceedings of the 2003 IEEE International Symposium on Circuits and Systems, Bangkok, 25 May 2003 through 28 May 2003 ; Volume 3 , 2003 , Pages III383-III386 ; 02714310 (ISSN) Kaboli, Sh ; Zolghadri, M. R ; Sharif University of Technology
    2003
    Abstract
    Flux spectrum is greatly influenced by flux and torque controller hysteresis loops (dead bands) in direct torque control of AC motors. On the other hand iron loss in induction motor is closely related to flux harmonics. Hence flux spectrum must be observed in control process to minimize the motor losses. In this paper the relation between the magnetic-flux spectrum and electromagnetic-torque and magnetic-flux controller hysteresis loops (dead bands) as well as machine parameters is investigated. Simulation results are presented to justify the results  

    Direct torque control of induction motor by active learning method

    , Article PEDSTC 2010 - 1st Power Electronics and Drive Systems and Technologies Conference, 17 February 2010 through 18 February 2010, Tehran ; 2010 , Pages 267-272 ; 9781424459728 (ISBN) Ghorbani, M. J ; Akhbari, M ; Mokhtari, H ; Sharif University of Technology
    2010
    Abstract
    This paper presents a high performance direct torque control (DTC) theme for the induction motor (IM). To solve those problems associated with conventional DTC, such as flux and torque ripple, variable switching frequency, inaccuracy in motor model and other parts of system. The Active Learning Method (ALM) is implemented on the DTC. In the Active Learning Method for information modeling, a method known as Ink Drop Spread (IDS) is used. The simulation results of DTC system based on ALM and the comparison of motor performance under the proposed control system with respect to those obtained under conventional DTC confirms its effectiveness and accuracy  

    An Improved aggregated model of residential air conditioners for FIDVR studies

    , Article IEEE Transactions on Power Systems ; Volume 35, Issue 2 , 2020 , Pages 909-919 Hajipour, E ; Saber, H ; Farzin, N ; Karimi, M. R ; Hashemi, S. M ; Agheli, A ; Ayoubzadeh, H ; Ehsan, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Stalling of residential air conditioners (RACs) following a transient fault can delay the voltage recovery ranging from 3 to 20 seconds. This phenomenon is referred to as fault-induced delayed voltage recovery (FIDVR). Several aggregated RAC models have been presented to replicate the actual FIDVR events. However, they usually have two main drawbacks as: i) considering independent stalling voltage and stalling time for all RACs, ii) resulting in only two ultimate modes; either 100% stalled or 100% normal running. This paper amends the abovementioned shortcomings by proposing a simple and effective performance-based RAC model. The proposed model utilizes a simple explicit relation between the... 

    Probabilistic voltage harmonic analysis of direct torque controlled induction motor drives

    , Article IEEE Transactions on Power Electronics ; Volume 21, Issue 4 , 2006 , Pages 1041-1052 ; 08858993 (ISSN) Kaboli, S ; Vahdati Khajeh, E ; Zolghadri, M. R ; Sharif University of Technology
    2006
    Abstract
    In high frequency motor-drives such as direct torque controlled (DTC) induction motor drives, the motor harmonic loss, and electromagnetic interference are largely affected by the spectrum of the motor input voltage. Nonlinear elements in the control loop of DTC drive make harmonic analysis of the drive very complex compared to classical pulsewidth modulated controlled drives. In this paper, a probabilistic method to study the harmonic contents of voltage in DTC of induction motors is presented. The DTC voltage chain is simulated with a random process. Then, the autocorrelation function of voltage vectors is calculated and its power spectrum density is obtained. The effect of flux and torque... 

    Performance analysis of outer-rotor single-phase induction motor based on magnetic equivalent circuit

    , Article IEEE Transactions on Industrial Electronics ; Volume 68, Issue 2 , 2021 , Pages 1046-1054 ; 02780046 (ISSN) Saneie, H ; Nasiri Gheidari, Z ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    Single-phase, outer-rotor squirrel cage induction motors are widely used in ceiling fan applications. Furthermore, they can be employed for pumps, and in-wheel hub drives. In this article, an analytical model based on magnetic equivalent circuit is proposed to evaluate the performance of the motor. The influence of rotor slots' skewing, stator end windings, slots' leakage inductance, and core saturation are included in the model. Furthermore, the windings' copper losses and the core's iron losses are calculated using the proposed model. The results of the presented model are compared with those of time variant finite element analysis (TVFEA) and experimental measurements close agreement... 

    A novel torque hysteresis comparator for torque and current ripple reduction of direct torque control of induction machine

    , Article 9th IEEE International Power Electronics Congress, CIEP 2004, Celaya, Gto, 17 October 2004 through 22 October 2004 ; 2004 , Pages 140-145 Keyhani, H. R ; Zolghadri, M. R ; Haghbin, S ; Sharif University of Technology
    2004
    Abstract
    The notable effeets of time delay aid time discretization on the torque and current ripple amplitude of the direct torque controlled induction motor scheme are investigated. A simply modified torque hysteresis comparator structure is proposed. It minimizes the undesirable effects of the time delay and time discretization on the torque ripple and allows a sensible reduction of torque and current ripple amplitudes and switching frequency in the whole rotor speed range. Numerical simulations and experimental tests have been carried out to validate the proposed torque comparator effect. © 2004 IEEE  

    Hysteresis band determination of direct torque controlled induction motor drives with torque ripple and motor-inverter loss considerations

    , Article 2003 IEEE 34th Annual Power Electronics Specialists Conference, Acapulco, NM, 15 June 2003 through 19 June 2003 ; Volume 3 , 2003 , Pages 1107-1111 ; 02759306 (ISSN) Kaboli, S ; Zolghadri, M. R ; Emadi, A ; Sharif University of Technology
    2003
    Abstract
    The flux and torque hysteresis bands are the only gains to be adjusted in direct torque control (DTC). The torque ripple and harmonic loss of motor and switching loss of inverter greatly Influence them. Hence, these variables must be observed in the control process to maximize performance of the system. In this paper, the effects of flux and torque hysteresis bands on inverter switching loss, harmonic loss, and torque ripple of induction motor are investigated. In order to find their optimum values, a cost function consisting motor harmonic losses, torque ripples, and inverter switching losses is defined. Minimizing this cost function leads to the optimum value of the hysteresis bands of... 

    Effects of sampling time on the performance of direct torque controlled induction motor drive

    , Article IEEE International Symposium on Industrial Electronics, ISIE 2003, 9 June 2003 through 11 June 2003 ; Volume II , 2003 , Pages 1049-1052 ; 0780379128 (ISBN) Kaboli, S. H ; Zolghadri, M. R ; Homaifar, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2003
    Abstract
    The torque ripple and harmonic loss of motor and switching loss of inverter are greatly influenced by sampling time in the direct torque control method. Hence these variables must be observed in the control process to maximize performance of the system. In this paper the effects of sampling time on inverter switching loss, harmonic loss and torque ripple of induction motor are investigated. To find their optimum values a cost function consisting of motor harmonic losses, torque ripples and inverter switching losses are defined. Minimizing this cost function leads to the optimum value of the sampling time. © 2003 IEEE