iosr-JEEE   International Conference on Advances in Engineering & Technology – 2014 (ICAET-2014)

Abstract: A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or a mis-operation of end user equipments. Utility distribution networks, sensitive industrial loads and critical commercial operations suffer from various types of outages and service interruptions which can cost significant financial losses. With the restructuring of power systems and with shifting trend towards distributed and dispersed generation, the issue of power quality is going to take newer dimensions. In developing countries like India, where the variation of power frequency and many such other determinants of power quality are themselves a serious question, it is very vital to take positive steps in this direction .The present work is to identify the prominent concerns in this area and hence the measures that can enhance the quality of the power are recommended. This work describes the techniques of correcting the supply voltage sag interruption in a distributed system. At present, a wide range of very flexible controllers, which capitalize on newly available power electronics components, are emerging for custom power applications A D-STATCOM injects a current into the system to correct the voltage sag, interruption. Results are presented to assess the performance of device as a potential custom power solution. The validity of proposed method and achievement of desired compensation are confirmed by the results of the simulation in MATLAB/ Simulink.

Keywords: D-Statcom,, voltage dips, interruption, power quality, VSC.

[1] N.G.Hingorani,"Flexible AC Transmission", IEEE Spectrum, vol. 30, pp.40-44,1993. [2] N.G.Hingorani, "Introducing Custom Power", IEEE Spectrum, vol. 32 pp.41-48,1995. [3] Anaya-Lara O, Acha E., "Modeling and analysis of custom power system by PSCAD/EMTDC", IEEE Transactions on Power Delivery, Vol.17, and Issue: 1, Jan. 2002. Pp.266-272. [4] M.J.H.Bollen, "Voltage sags in three-phase system" Power Engineering Review, IEEE, Vol.21 Issue:9, Sept.2001.pp.8-11. [5] Haque. M.H, "Compensation of distribution system voltage sag by DVR and D-STATCOM". Power Tech. proceeding. 2001IEEE Porto, vol.11, Issue: Sept. 2001 pp.10-13 [6] Arindam Ghosh, "Performance Comparision of VSC-Based Shunt and Series Compensators Used for Load Voltage Control in Distribution System".IEEE Transaction on power delivery, vol.26, No.1, Jan, 2011. pp.268-278. [7] Arindam Ghosh, "Copensation of Distribution System Voltage Using DVR". IEEE Transaction on power delivery, vol.17, No.4, Oct. 2002. pp.1030-1036. [8] H.P Tiwari and Sunil Kumar Gupta "Dynamic Voltage Restorer against Voltage Sag" International of Innovation, Management and Technology vol.03, pp. 232-237,2010. [9] C.S Chang, Y.S Ho, "The Influence of Motor Load on the Voltage Restoration Capability of Dynamic Voltage Restorer". Power System Technology, Proceedings, Power Con, International Conference, vol.2,pp. 637-642,2000. [10] M.H. Rashid, "Power Electronics" 2nd edition, Elsevier, Inc, Publication, Californial, U.S.A 2007.

Abstract: AC motors are widely used in industries for motion control systems. The advantages of using induction motor over dc motor are rugged construction, high efficiency and maintenance free operation. For electrical drives good dynamic performance is mandatory so as to respond to the changes in command speed and torque. These requirements of AC drives can be fulfilled by the vector control system. With the advent of the vector control method, an induction motor has been controlled like a separately excited DC motor for high performance applications. This method enables the control of field and torque of induction motor independently (decoupling) by manipulating corresponding field oriented quantities. Conventional PI controller regulates the speed and flux value depending upon the given reference. In the outer speed loop of the indirect vector control, the PI controller is used to generate the torque command so as to regulate the actual speed same as the reference speed. This is a simple controller and gives stable operation of motor when tuned properly. But unexpected load changes and environmental conditions cause overshoot, oscillations in motor speed, oscillations of torque, long settling time and thus the deterioration of motor performance. These off line tuned controllers are difficult in dealing because of the continuous motor parameter variation and non-linearity present in the entire system. This problem can be overcome using on line gain adaptive controllers. The fuzzy based intelligent controller can be implemented in place of PI controller. There is some advantage of fuzzy logic controller as compared to conventional PI, PID and adaptive controller such as it does not require any mathematical model, it is based on linguistic rule which is the basis of the human logic. When fuzzy logic based intelligent controller is used instead of PI controller, excellent control performance is achieved even in the presence of parameter variation and drive non-linearity.

Keywords -Vector control, Induction motor, Fuzzy logic controller, speed control and space vector PWM.

[1] AN2388 Application note, "Sensor field oriented control (IFOC) of three-phase AC induction motors using ST10F276", Texas Instruments. [2] Biranchi Narayan Kar, K.B. Mohanty, "Indirect Vector Control of Induction Motor Using Fuzzy Logic Controller" [6] For use with Matlab, "Fuzzy logic's user guide", Fuzzy logic toolbox, MATLAB. Conference/Journal Papers: [4] P.Tripura and Y.Srinivasa Kishore Babu, "Fuzzy Logic Speed Control of Three Phase Induction Motor Drive", World Academy of Science, Engineering and Technology 60, 2011. [5] K. Kouzi, L. MokraniM-S. Nait-Said, "A New Design of Fuzzy Logic Controller with Fuzzy Adapted Gains Based on, Indirect Vector Control for Induction Motor Drive", IEEE proceedings of the 35th Southeastern Symposium on System Theory, 2003. Page(s):362-366 [7] Norman Mariun, SamsulbahariMohd Noor, J. Jasni and O. S.Bennanes, "A Fuzzy Logic based Controller for an Indirect VectorControlled Three-Phase Induction Motor", IEEE Region 10 Conference, TENCON 2004, Volume D, Issue. 21-24 Nov. 2004 Page(s): 1-4 Vol. 4

Abstract: In this paper, a simplified space–vector pulse width modulation technique for multilevel inverters is proposed. This method is based on the simplification of the space–vector diagram of a five level inverter into that of a three level inverter. In turn, the three level inverter space vector diagram is simplified into that of two level inverter. Hence, the algorithm of five level space-vector pulse width modulation become very similar to that of conventional two level inverter If simplified by the proposed method, all the remaining procedures necessary for the three-level and five level inverter SVPWM are done like conventional two-level inverter and the execution time is greatly reduced. The dc-link neutral-point potential control algorithms are implemented more easily. And the proposed method can be applied to the multi-level inverters above three and five level.

Keywords- Multilevel inverter, three level inverter, five level inverter, and space-vector PWM method

[1] Jae Hyeong Seo, Dong Seok Hyun and Chang Ho Choi "A New Simplified Space–Vector PWM Method for Three-Level Inverters" IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 16, NO. 4, JULY 2001 [2] Dj. Lalili, N. Lourci, E.M. Berkouk, F. Boudjema , J. Petzoldt and M.Yasin Dali "A Simplified Space Vector Pulse Width Modulation Algorithm For Five Level Diode Clamping Inverter" SPEEDAM 2006 International Symposium on Power Electronics, Electrical Drives, Automation and Motion. [3] Amit Kumar Gupta and Ashwin M. Khambadkone "A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM" IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 53, NO. 5, OCTOBER 2006 [4] José Rodríguez, Luis Morán, Pablo Correa and Cesar Silva "A Vector Control Technique for Medium-Voltage Multilevel Inverters" IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 49, NO. 4, AUGUST 2002 [5] Gerardo Ceglia, Víctor Guzmán and María I. Giménez "A New Simplified Multilevel Inverter Topology for DC–AC Conversion" IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 21, NO. 5, SEPTEMBER 2006

Abstract: Stressed power system, either due to increased loading or due to severe contingencies, it will lead to situation where system no longer remains in the secure operating region. Under these situations, it is primary objective of the operator to apply control action to bring the power system again into the secure region. Any delay or unavailability of suitable control leads to the unstable system. In fact, contingencies results into voltage limit violations and leads to overloading of lines. The system overloading can be recover by two alternatives firstly by restructuring the power system and secondly by controlling the line parameters. The Power system restructuring requires expanding unused potentials of transmission systems but environmental, right-of-way, and cost problems are major hurdles for power transmission network expansion. Nowadays, FACTS devices are used as an alternative to reduce the flows in heavily loaded lines, it will results in an increased loading, low system loss, improved stability of the network, reduced cost of production. In this paper, first contingency conditions are analyzed after that according to severity of contingency a real power flow performance index (PI) sensitivity based approach and the line outage distribution factor has been used to decide optimal location of series FACTS devices ,Thyristor controlled series compensator(TCSC) and Thyristor controlled phase angle regulator(TCPAR) to restabilize the system. The effectiveness of the proposed controller has been tested on modified IEEE 14 bus system using Power world simulator 12.0 software. Keywords: Optimal location of series FACTS device, Thyristor controlled series compensator (TCSC), Thyristor Controlled Phase Angle Regulator (TCPAR), Contingency analysis, Sensitivity (Severity) index method, Line outage distribution factor (LODF) , Power World Simulator Software version 12.0.

[1] S.N.Singh, " Location of FACTS devices for enhancing Power systems security", power Engineering 2001, "LESCOPE‟ 01, 2001 Engg large engg system conference on 2001. pg no.162-166 [2] J.G. Singh, S.N. Singh and S. C. Srivastava, "Placement of FACTS controllers for enhancing power system Load ability", IEEE Trans. On power delivery, vol 12, No. 3, July 2006 [3] R.Narmatha Banu D.Devaraj, "Optimal Power Flow for Steady state security enhancement using Genetic Algorithm with FACTS devices", 2008 IEEE Region 10 Colloquium and the Third ICIIS, Kharagpur, pp-1-6,2008. [4] P.S.vaidya, V.P.rajderkar, "Optimal location of series FACTS devices for enhancing power system security", 2011 IEEEE computer society, pp-185-190. [5] Mrs. Veenavati Jagadishprasad Mishra & Prof. Manisha D. Khardenvis, "Contingency Analysis of Power System" , 2012 IEEE Students‟ Conference on Electrical, Electronics and Computer Science, 2012 [6] Jondea kim, Victor wong, Gamal maria, "Contingency ranking and simulation for on-line use", IEEE Transactions on Power Apparatus and Systems, Vol. PAS-104, No. 9, September 1985, pp-2401-2407. [7] F.M. EL-Kady, "Contingency analysis in the presence of Series FACTS in power System"2001 IEEE, pp-241-246 , 2001. [8] Ejebe G. C. and Wollenberg, B. F., "Automatic Contingency Selection", paper F78 228-9, presented at the IEEE-PES Winter Meeting, New York, NY, January 1979.

Abstract: Congestion Management is one of the major tasks performed by system operators to ensure the operation of transmission system within operating limits. In the emerging electric power market the congestion management becomes extremely important and it can impose a barrier to the electricity trading. The method of congestion management based on Optimal Power flow are proposed to alleviate congestion in transmission lines and tested. This method requires re-dispatching on the basis of economic cost involved in making required changes to re-dispatching method. Alleviation of the emergency transmission line overload is a Critical problem in the present day power system operation; hence a control strategy is necessary to effectively reduce the line overloads to the security limits in the shortest time, by generation re-dispatching, not giving priority to the economic consideration. In the literature many methods have been reported for determining a secure operating point. Most of these methods use conventional optimization techniques, which are generally time consuming from computation point of view, especially for large systems. Further the conventional optimization techniques update all the controllers for most of the operating conditions. Under emergency conditions the operator has to make quick decisions, with little concern for the theoretical optimality of the operating point and also the operator cannot move all the controllers to different settings within less time. In this context a simplified expert system approach has been proposed in this paper for security and economy oriented power system operation. The proposed approach is used to remove the congestion in transmission line by generation re-dispatching. This paper presents a software tool for congestion management. The congestion management is based on a reformulated optimal power flow, whose main goal is to obtain a feasible solution for the re-dispatch minimizing the changes in the dispatch proposed by the market operator. The calculation is performed by MATPOWER fronted software with Graphic user interface facilities. Under emergency operating conditions the proposed approach helps the operator in load dispatch centre for improving the system security with the re-dispatching the few number of generators for overload relieving with less incremental fuel cost. The Paper includes a case study for IEEE 9 bus power system.

Keywords: Congestion Management, Optimal Power flow

[1] A.J. Wood and B.F. Wollenberg, Power generation, operation and control: John Wiley and sons,Inc.1996.

[2] P. F. Penner, Electric Utility Restructuring: A guide to the competitive Era. Vienna, VA: Public utilities reports Inc. 1997.

[3] F. Nishimura, R.D. Tabors, M. D. IIic and J. R. Lacalle-Melero, " Benefit-optimization of centralized and decentralized power system in a multi-utility environment", IEEE transactions Aug 1993,PWRS vol 8, No. 3 pp.1180-1186.

[4] H. Rudnick, " Pioneering Electricity reform in south America" , IEEE spectrum pp. 38-44 , Aug 1996.

[5] S. Soft, " Power system economies: Designing Markets for electricity" Available: http/www.stoft.com/x/book/index.shtml.

[6] J. Bower, D. Bunn, " A model based comparison of Pool and Bilateral market mechanism for electricity Trading", Energy Market group, London Business School, May 1999. [7] Surachai Chaitusaney, Naebboon Hoonchareon, Bundhit Eua-Arporn, " Generation dispatch with Pool and Bilateral Coordination", IEEE transaction on power system 2002 pp. no. 1355-1359.

Abstract: Transmission Pricing has been an important issue on the ongoing debate about power system restructuring and deregulation. The purpose of the transmission pricing is to recover cost of transmission encourage efficient use & investment. This paper aims to establish a methodology for evaluating the wholesale or retail prices in a power market which ensures not only the recovery of expense for utilities or regional networks but also provide reasonable electricity prices for consumers, reflecting the market competition. In the power market under consideration it is assumed that there are multiple IPPs (Independent Power Producers) bidding electric power to a utility or regional network, and that the utility supplies electric power to customers by a fixed transmission network. By looking at current publications on electricity markets liberalization it becomes obvious that the question is no longer if competition should be introduced but how to organize markets in order to achieve an optimum performance. Power delivery is nowadays a bundle of many services including mainly generation, transmission and distribution. This paper focuses on problems related to energy transmission and its pricing in an open electricity markets. This paper presents a software tool for transmission price determination in electricity market. It also presents and analyses several approaches for transmission cost allocation in a centralized pool based electricity market environment that include composite marginal transmission pricing mechanism. It also highlights the need of pricing simulator with techno-economical analysis of trading philosophy with background calculations performed by MATPOWER. The transmission price computation considers the physical impact caused by the market agents in the transmission network. It includes existing system costs and also costs due to the initial congestion situation and losses costs. The paper includes a case study for the IEEE- 9 bus power system.

Keywords: Transmission Pricing, Optimal power flow.

[1] A.J. Wood and B.F. Wollenberg, Power generation, operation and control: John Wiley and sons,Inc.1996. [2] P. F. Penner, Electric Utility Restructuring: A guide to the competitive Era. Vienna, VA: Public utilities reports Inc. 1997. [3] F. Nishimura, R.D. Tabors, M. D. IIic and J. R. Lacalle-Melero, " Benefit-optimization of centralized and decentralized power system in a multi-utility environment", IEEE transactions Aug 1993,PWRS vol 8, No. 3 pp.1180-1186. [4] H. Rudnick, " Pioneering Electricity reform in south America" , IEEE spectrum pp. 38-44 , Aug 1996. [5] S. Soft, " Power system economies: Designing Markets for electricity" Available: http/www.stoft.com/x/book/index.shtml. [6] J. Bower, D. Bunn, " A model based comparison of Pool and Bilateral market mechanism for electricity Trading", Energy Market group, London Business School, May 1999. [7] Surachai Chaitusaney, Naebboon Hoonchareon, Bundhit Eua-Arporn, " Generation dispatch with Pool and Bilateral Coordination", IEEE transaction on power system 2002 pp. no. 1355-1359. [8] M. Judite Ferreira, Zita A vale, Jose Cardoso, " A Congestion Management and transmission Price Simulator for competitive Electricity Market" , IEEE transaction on power system 2007 pg. no.1-7.

Abstract: Optimization of active power loss in Electrical Power systems is complicated because of large, complex, and geographically widely distributed power systems. It is advisable to use the most efficient optimization technique based on its suitability to find an optimized solution of the problem. Active power loss minimization in a system is obtained by controlling the flow of reactive power. The reactive power flow control can be achieved through generator bus voltage, transformer tappings and shunt capacitor banks. An overview of different artificial intelligence (AI) optimization techniques used in power optimization problems are discussed in this paper. Hybrid or improved AI techniques having peculiar characteristics are also presented. This paper studies different techniques implemented for active power loss minimization.

Keywords: Artificial intelligence, genetic algorithm, particle swarm optimization, active power loss minimization, reactive power optimization.

[1] D.E. Goldberg. Genetic Algorithms in Search, Optimization and Machine Learning. Addison-Wesley, New York, 1989. [2] Kenji Iba, ―Reactive Power Optimization by Genetic Algorithm‖, IEEE Transactions on Power Systems, Volume 9, Issue 2, May 1994, pp 685-692.

[3] Yuhui Shi, Russell C. Eberhart, "Empirical Study of Particle Swarm Optimization", Evolutionary Computation, CEC 99, Vol 3, 6-9 July 1999.

[4] Yuhui Shi, Russell C. Eberhart, ―Comparing Inertia Weights and Constriction Factors in Particle Swarm Optimization‖, Proceedings of the Congress on Evolutionary Computation, La Jolla, CA, Vol1, 2000, pp:84-88. [5] M.A. Abido, "Optimal Power Flow using Particle Swarm Optimization", International Journal of Electrical Power and Energy Systems, Elsevier, Vol24, Issue 7, October 2002, pp:563-571

[6] A. H. Mantawy, M. S. Al-Ghamdi, "A New Reactive Power Optimization Algorithm", IEEE Bologna PowerTech Conference, June 23-26, Bologna, Italy

[7] Wen Zhang, Yutian Liu, "Reactive Power Optimization Based on PSO in a Practical Power System", IEEE Power Engineering Society General Meeting, Vol.1, 6-10 June 2004, pp:239 - 243 [8] J. Hazra, A. K. Sinha, "A Study on Real and Reactive Power Optimization using Particle Swarm Optimization", Second International Conference on Industrial and Information Systems(ICIIS-2007), 8 – 11 August 2007, Sri Lanka

Abstract: The aim of this paper is to automate the operation of Gummer using Advance drive rectifying system (IGBT).For highly control dynamic and motion control application, for demanding the highest degree of seed and torque accuracy over a large speed control range and for a group drives. This application enables innovative, customized drive solution, enable quick and easy extension and modification of drive concept, enables customer requirement to be met both flexibly and economically, reduces engineering cost. This is the time for an attempt to design a point to point control technique on AC servo motor position control systems. The object of this Paper is to simplify the machine with great accuracy. Mechanical part incredibly replacing by drives with intelligent positioning control. There are several application of drives control. Basically Gummer is design to operate on mechanical gear and cam follower system which is having large drawback of accuracy in degree and cutting system.

Keywords: Gummer machine,AC servo motor, delinting ,IGB

[1] JOON HYUK KANG, CHUNG HYUK YIM, AND DONG I1 KIM, "ROBUST POSITION CONTROL OF AC SERVO MOTORS" 0-7803-3026- 9/95 1995 IEEE.
[2] DONGMEI YU, QINGDING GUO AND QING HU"POSITION CONTROL OF LINEAR SERVO.SYSTEM USING INTELLIGENT FEEDBACK
a. CONTROLLER" INTERNATIONAL CONFERENCE ON INTELLIGENT SYSTEMS DESIGN AND
b. APPLICATIONS (ISDA'06)0-7695-2528-8/06 © 2006.
[3] K. Zagar, A. Vodovnik, "Program Generators and Control System Development",
a. PCaPAC 2002,Frascati,Oct 2002
[4] Firoozian, Riazollah "Industrial Servo Control Systems: Fundamentals and Applications" Second edition
a. Revised and expanded By Fond du lac
[5] http://www.compumotor.com/catalog/cataloga/A72-A96.pdf
[6] http://www.indiamart.com/soniinds/cotton-processing-machinery.html.

Abstract: A number of Flexible AC Transmission System (FACTS) controllers based on the rapid development of high power electronics technology have been proposed in recent years for better utilization of existing transmission facilities. FACTS devices have shown very encouraging results for improvement of power system steady state performance. Unified Power Flow Controller (UPFC) is a versatile FACTS device which has the ability to adjust the three control parameters, i.e. the bus voltage, the transmission line reactance, and the phase-angle between two buses. During transients, it can be used to improve the damping rate of low frequency oscillations. Multi-Machine (3-machines 9-Bus) electrical power system incorporated with UPFC has been simulated in the present work with the aim of analyzing the response of the device for enhancing transient stability of the electrical power system. LabVIEW tool has been used for the simulation purposes. LabVIEW is a new research tool which is capable of representing dynamic systems in block diagram form, along with a provision of simulation of system behavior in total. Results obtained are encouraging and indicate that the proposed simulation model is very near to the physical simulation.

Keywords- LabVIEW, FACTS, Transient Stability, UPFC.

1] G. Hingorani, L. Gyugyi, "Understanding FACTS Concepts Technology of Flexible AC Transmission Systems", IEEE Press, New York, 2000.

[2] S.Tara Kalyani, G.Tulasiram Das, "Simulation of Real and Reactive Power Flow Control with UPFC Connected to a Transmission Line", Journal of Theoretical and Applied Information Technology, pp 16-22, 2008.

[3] M.L.Kothari and N. Tambey, "Design of UPFC Controllers for a Multimachine system", IEEE PES Power System Conference and Exposition, Vol.3, pp 1483-1488, 2004.

Abstract: The aim of this paper is the study of speed sensorless control of IM drive by using dc link quantities. The sensorless control method is to determined the appropriate moment when the motor winding should be commutated. This moment is determined by the rotor position. In this type of drive, the limitations of using various sensors for the measurement of rotor speed, stator current & voltages are minimized by estimating these quantities with the help of algorithms. The aim of reconstruction is to achieve the required motor output without exceeding either the short-term or the long-term motor and inverter ratings. These restraints inevitably mean that a number of working currents within the drive must be monitored. All these currents are difficult to measure accurately in the presence of high di/dt and dv/dt switching transients. In a three-phase motor, at-least two motor phase currents must be measured. It is difficult to get current sensors with equal gain over a wide range of frequencies, voltages and currents used in a practical inverter. Therefore we are using the stator current reconstruction method to reduce the physical sensors. The input current and voltage signals to the speed estimation algorithm are the reconstructed waveforms of stator current & voltages obtained from the dc link & not directly on the stator side. In this paper, the focus is given on study of DTC and compare its performance with other speed controlling techniques such as scalar and vector control. A current sensor is usually present in the dc link of most drives that is employed for the over current protection. To reconstruct the three phase currents from the dc link, information regarding the inverter switching states is required. The whole studies has been performed in MATLAB/Simulink environment.

Keywords - Induction motor, space vector PWM, DTC, sensorless control, reconstruction.

[1] Paul.C.Krause, "Analysis of Electrical Machinery", Mc-Graw-Hill, 1986.

[2] B.K.Bose, "Morden Power Electronics and AC Drive", Prentice-Hall, 2002.

[3] Peter Vas , "Sensorless Vector and Direct Torque Control" Published in the United States by Oxford University Press,Inc.,New York,1998. [4] Maurizio Cirrincione , Marcello Pucci and Gianpaolo Vitale, "A Novel Direct Torque Control of an Induction Motor Drive with a Three-Level Inverter", IEE Conference on Power Tech, Italy, June 2003. [5] F.Khoucha, K.Marouani, K.Aliouane and A. Kheloui, "Experimental Performance Analysis of Adaptive Flux and Speed Observers for Direct Torque Control of Sensorless Induction Motor Drives, IEEE Conference on Power Electronics Specialists, Germany, pp. 2678-2683, 2004. [6] D. Casadei, G. Serra, A. Tani, and L. Zarri, "Assessment of direct torque control for induction motor drives", IEEE Trans, Technical Sciences, Vol. 54, No. 3, 2006.

[7] S. B. Bodkhe and M. V. Aware, "Speed-sensorless, adjustable-speed induction motor drive based on dc link measurement", International Journal of Physical Sciences Vol. 4 (4), pp. 221-232, April, 2009.

Abstract: The basic scheme presents a contribution for detailed comparative analysis between Field- Oriented Control and Direct Torque Control techniques for high performance induction motor drive. The toque and flux are controlled simultaneously by applying suitable voltage vectors, and by limiting these quantities within their hysteresis bands, de-coupled control of torque and flux can be achieved. This paper presents the evaluation technique of space vector modulation applied to the induction machines. The simulations were carried out using MATLAB/SIMULINK simulation package. Evaluation is made based on the drive performance, which includes dynamic torque and flux responses, feasibility and the complexity of the systems. However, the basis of DTC SVM strategy is the calculation of the required voltage space vector to compensate the flux and torque errors exactly by using a predictive technique and then its generation using the Space Vector Modulation. We can note a slight advance of DTC scheme compared to FOC scheme regarding the dynamic flux control performance and the implementation complexity. The choice of one or the other scheme will depend mainly on specific requirements of the application. General Terms : Sector implementation, ripple in torque, ripple in current, inverter states. Keywords: Induction motor, Field oriented control (FOC), Direct torque control (DTC), Sensorless, Space Vector Pulse Width modulation (SVPWM).

[1] Naceri Farid*, Belkacem Sebti†, Kercha Mebarka and Benmokrane Tayeb* University of Batna/Department of Electrical Engineering, Batna, Algeria" Performance Analysis of Field-Oriented Control and Direct Torque Control for Sensorless Induction Motor Drives"July27-29, 2007, Athens-Greece T21-002
[2] F. Parasiliti, "Appunti delle lezioni di Azionamenti Elettrici: Controllo Vettoriale and Orientamento di Campo", Università degli Studi di L‟Aquila
[3] R. Di Gabriele, F. Parasiliti, M. Tursini, "Digital Field Oriented Control for induction motors: implementation and experimental results", Universities Power Engineering Conference (UPEC‟97)
[4] Riccardo Di Gabriele, "Controllo vettoriale di velocità di un motore asincrono mediante il Filtro di Kalman Esteso", Tesi di Laurea, Università degli Studi di L‟Aquila, Anno Accademico 1997-98
[5] L.Zhang, C. Wathanasarn, F. Hardan, "An efficient Microprocessor-Based Pulse Width Modulator using Space Vector Modulation Strategy", IEEE 1994
[6] Satoshi Ogasawara, Hirofumi Akagi, Akira Nabae, "A novel PWM scheme of Voltage Source Inverters based on Space Vector Theory", EPE Aachen 1989 [8] Joachim Holtz, "Pulsewidth Modulation-A Survey", IEEE 1992
[7] Werner Leonard, "Control of Electrical Drives", 2nd Completely Revised and Enlarged Edition, Springer
[8] F. BLASCHKE, « The principle of field oriented as applied to the new Tran- vector closed-loop control systems for rotating machines », Siemens Rev, vol. 39 n°4, pp .217-220, 1972.
[9] C. Lascu, I. Boldea, and F. Blaabjerg, « A modified direct torque control for induction motor sensorless drive », IEEE Trans. Industry Appl, vol. 36, pp .122-130, Jan/Feb 2000.
[10] Takahashi , T. Noguchi, « A new quick-response and high efficiency control strategy of an induction machine » IEEE Trans. Industry Appl, vol. 22, pp. 820-827, Sep/Oct 1986.

Abstract: Direct torque control method is a powerful control technique for specially Induction motor drive. Now a days Direct Torque Control using Digital signal processors more popular in the ac motor control, in particular the induction motor drives. The quick response and smooth control of DSP's are being utilized to perform real time simulation on the ac motor variables, such as electromagnetic torque, fluxes, mechanical speed, etc. This paper presents the implementation of a high performance induction motor control technique known as direct torque control (DTC) utilizing three level inverter and compare between basic DTC scheme and modified DTC scheme(Three level inverter) to minimize the sampling period of the implemented drive system, DTC drives. Experimental results of this high performance drive system on a5hp standard induction motor are as expected and agree with the theoretical work Index term: Induction motor3phase, 5HP, Voltage source Inverter

[1] Yatim A.H.M ;Idris N.R.N "Implementation of Direct torque control of induction machine utilizing TMS320C31digital signal processor",Signal Processing and Its Application, Sixth International,Symposium,2001volume :2 digital object identifier; 10.1109/ISSPA.2001.950223,publication year:2001,pages:627-630

[2] Toh, C.L.; Idris, N.R.N.; Yatim, A.H.M.;Muhamad,N.D.; Elbuluk, M."Implementation of New Torque and Flux controllers for Direct Torque Control (DTC) of Induction Machine Utilizing Digital Signal Processor(DSP)" ,Power Electronics Specialists Conference,2005,Pages:1594-1599. P ESC''05 IEEE 36th digital Object Identifier: 10.1109 /PESC.2005.1581843Publication Year: 2005 , Page(s): 1594 - 1599

[3] Toh,C.L.;Idris,N.R.N.;Yatim,A.H.M.;Muhamad,N.D;Elbuluk,M " Implementation of a New Torque and flux Controllers for Direct Torque control of Induction Machine Utilizing Digital Signal Processor and Field programmable Gate Arrays" Power Electronics Zhou, L.Q. " DSP- controlled Direct Torque Control of Induction Machines" ,Industrial Electronics and Application ,2007.ICIEA 2007.2nd IEEE conference on Digital Object Identifier: 10.1109/ICIEA.2007.4318718,Publication year :2007,pages:1790-1793IEEEconference Publication