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INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROLInt. J. Robust Nonlinear Control 2004; 14:767769 (DOI: 10.1002/rnc.811)

BOOK REVIEW

electric motor drives: modeling, analysis

and control, R. Krishan, Prentice-Hall, UpperSaddle River, NJ, 2001, xxviii + 626 pp. ISBN 0-13-0910147

1. INTRODUCTION

This newly published textbook, by R. Krishnan, aprofessor at Virginia Tech, Blacksburg, VA,presents the basic concepts of power converter-fed drive technology including DC and ACinduction and permanent magnet motors. In asystematic way each chapter address the study ofsteady-state and dynamic performance followedby design of controllers and their implementation.Control algorithms and an analysis have beencarried out to facilitate dynamic simulation usingpersonal computers. Theoretical considerationsare supported by 48 clearly explained examplesand simulation. Moreover, each chapter is sup-plemented with an illustrative drive exampleselected from industrial environment, short com-ments to present research status, list of references,review questions and exercise problems.

2. GENERAL COMMENTS ANDCONTENTS OF THE BOOK

Most of the text and reference books devoted tocontrol of converter-fed drives published in thelast decade are restricted to AC motor drives [18]. This is quite understandable, because ACmotors}especially induction cage rotor mo-tor}thanks to their simple construction, relia-bility, ruggedness, and low cost have found wideindustrial applications. Furthermore, in contrastto DC brush motors, they can be used inaggressive or volatile environments since thereare not problems with sparks and corrosion. Also,induction motor is much more attractive forcontrol engineers because is multivariable, non-linear and coupled system, which requires ad-vanced control methods. For mathematicaldescription of drive systems with AC motors, the

concept of aspace vectorsis commonly employed.However, in European countries (Europeanauthors) complex number representation [610]and in the USA two-axis real number representa-tion is preferred [1, 2, 4]. The space vector basedAC motor equations can be analysed in differentreference coordinates (frames), e.g. stationary orrotated. The co-ordinates rotating synchronouslywith the rotor (stator) flux linkage vector arecalled field coordinates. In the field coordinates}for constant rotor flux amplitude}there is alinear relationship between control variables andspeed. Moreover, like in a separately excited DC

brush motor, torque and flux can be controlledindependently (decoupling). Thus, the analogywith DC motor control is a basis ofField OrientedControl(FOC)}also known as Vector Control}which is now de facto standard in high perfor-mance AC industrial drives. Therefore, Author ofthe book under review starts from modeling(Chapter 2) and control of line converter-fed(Chapter 3) and chopper-fed (Chapter 4) DCmotor drives. These three chapters explain indepth the control properties of DC drives andcreate a good basis for understanding vectorcontrol of induction and permanent magnetmotor drives which are presented in further

Chapters 8 and 9, respectively. The four types ofAC motor drives (induction cage and wound rotormotor, permanent magnet synchronous motor(PMSM) and brushless DC motor) are covered inproper relation to their significance. Thus, I find itright to devote the largest portion to inductionmotor drives (over 300 from total 626 p).

The basic theory of three-phase inductionmotor including construction, operation, para-meter measurements, static characteristic, dy-namic modeling and space vector (phasor) modelis presented in Chapter 5. The operation ofdirect and indirect (based on voltage sourceinverter (VSI) and current source inverter (CSI))frequency changers as well as their interfacingwith induction machine are systematically dis-cussed in Chapter 7. In addition, also basic lowperformance speed control methods like constantVolts/Hz, constant slip frequency, and constantair gap flux, for variable frequency drives aredescribed.

ReceivedCopyright# 2004 John Wiley & Sons, Ltd. Revised

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Chapter 8 is devoted to vector control ofinduction motors and various schemes of directand indirect FOC are analyzed in connection withVSI- and CSI-fed drives. Also, such an importantproblems like flux and torque estimation, para-

meter sensitivity and its compensations, fieldweakening operation, and speed controller designare properly addressed in that Chapter. However,the classification adopted by Author for controlschemes seems to me inadequate. Based on thespace vector description of the AC motors, thecontrol systems for induction motor can be clearlydivided as follows [9, 1, 5]:

Scalar control (low dynamics): V/Hz control,stator current/slip frequency control,Vector control(high performance):Field oriented control (FOC)

(a) indirect FOC (K. Hasse),

(b) direct FOC (F. Blaschke),

Direct torque control (DTC)

(a) hexagon flux path (M. Depenbrock),(b) circular flux path (I. Takahshi and T.Nogouchi).

The title of the Section 8.3.5: Direct Vector(Self) Control in Stator Reference Frames withSpace-Vector Modulation is misleading becausethe term Space Vector Modulation}(SVM) is inpower electronics community commonly used formost popular pulse width modulation (PWM)algorithm [3, 11], whereas the method describedby Author is the switching table based DTC withcircular flux trajectory (see oscillograms in Fig-ure 8.13). So, in this scheme (Figure 8.12) there isno pulse width modulator, which calculatesswitching states of power transistors from refer-ence stator voltage vector according to a pre-scribed algorithm like SVM. The powertransistors are switched by selecting from theswitching table an appropriate voltage vector thatminimize instantaneous flux and torque errors.Note that SVM can also be used to implement thiscontrol scheme.

In the whole text Author used linear time-invariant continuous time models of the plants,

and controller design is systematically done basedon transfer function approach for both DC andAC drive systems. Consequently, the standardrules of controller parameter setting likesymmetryoptimum are used for current and speed/positionloops design. However, the principles and limita-tions of thesymmetry optimum and its connection

with modulus optimum are not explained in thebook. Also, I would expect more attention paid tothe problems related to digital controllers, becausepresented approach is valid only for continuousand/or fast sampled discrete systems. Especially,

predictive and dead-beat discrete controllers usedin PWM current regulated inverters are notdiscussed [11, 4].

Other important topics, such as control ofPWM rectifier/inverter-fed drives [2], double-fedinduction motor [10] as well as stator flux orientedcontrol [2, 3, 10] and decoupling in field orientedcurrent controller [9] are missing.

3. DETAILED COMMENTS

(a) The reference number given on p. 426 bottomshould be [53] not [46]!

(b) Symbols used in the book are not unified, e.g.compare PI controllers in Figure 3.26, 3.29, 6.24,7.18, 8.2, 8.24, 8.26, 8.39, 9.38, etc. Symbols usedin Figure 7.52 are totally different.(c) In Figure 7.18 the term 1=2p is needlessbecause the control loop is designed in per unitsystem.(d) The scheme shown in Figure 7.30 is known ascurrent programmed flux control [1] or slipfrequency/current control [10].(e) In figure 7.53(ii), cited figure number 7.54(i)must be 7.53(i).

4. CONCLUSIONS

The book under review, in spite of some criticalsuggestions given in Sections 2 and 3, is valuablecontribution to the fast growing multidisciplinaryarea of power electronic drive control. It includeswell-balanced text with good selected examples,which made all material easy and good under-standable for graduate-level course on converter-fed drives.

The group of modern nonlinear methodsdeveloped in the last decade, like exact lineariza-tion [1214], passivity based and backsteppingdesigns [15] are not included in the book. There isno doubt that they will offer a new, interesting

perspective for future research. However, from thepresent industrial point of view, they representonly an alternative solution to existing FOC andDTC schemes. Therefore, they need more researchefforts and understanding among power electro-nics and drive control specialists to be includedinto an academic textbook in coming decades.

Copyright # 2004 John Wiley & Sons, Ltd. Int. J. Robust Nonlinear Control2004; 14:767769

BOOK REVIEW768

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Finally, I recommend this attractive, up-to-datetextbook for a wide audience as an introductoryfollowed by advanced graduate course (twosemesters). Also, this book will be useful forpracticing engineers who are interested in modern

methods of drive control and design. Courseinstructors can obtain a copy of the 200 p.solutions manual with Matlab programs for mostof the exercise problems.

REFERENCES

1. Bose BK. Power Electronics and AC Motor Drives.Prentice-Hall: Englewood Cliffs, NJ, 1986.

2. Bose BK (Ed.), Power Electronics and VariableFrequency Drives. IEEE Press: New York, 1997.

3. Bose BK.Modern Power Electronics and AC Drives.Prentice-Hall: Englewood Cliffs, NJ, 2001.

4. Novotny DW, Lipo TA. Vector Control and

Dynamics of AC Machines. Oxford: ClarendonPress, 1996.5. Rajashekara K, Kawamura A, Matsue K.Sensorless

Control of AC Motor Drives. IEEE Press: NewYork, 1996.

6. Trzynadlowski AM. The Field Orientation Principlein Control of Induction Motors. Kluwer AcademicPublisher: Boston-Dordrecht-London, 1994.

7. Vas P. Vector Control of AC Machines. ClarendonPress: Oxford, 1990.

8. Vas P.Sensorless Vector and Direct Torque Control.Clarendon Press: Oxford, 1998.

9. Boldea I, Nasar SA. Electric Drives. CRC Press:Boca Raton-Ann Arbor-London-Tokyo, 1999.

10. Leonhard W.Control of Electrical Drives (2nd edn).Springer Verlag: Berlin, 1996.

11. Holtz J. Pulsewidth modulation for electronic powerconversion. In Proceedings of the IEEE 1994;82(8):11941214.

12. Bodson M, Chiasson J, Novotnak R. High perfor-mance induction motor control via input-outputlinearization. IEEE Control Systems, 1994; 2533.

13. Isidori A. Nonlinear Control Systems, Communica-tions and Control Engineering. Springer Verlag:Berlin (Sec. edn, 1989).

14. Marino R, Valigi P. Nonlinear control of inductionmotors: a simulation study. In European ControlConference, Grenoble, France, 1991; 10571062.

15. Ortega R, Loria A, Nicklasson PJ, Sira-Ramirez H.Passivity-based Control of Euler-Lagrange Systems.Springer Verlag: London, 1998.

16. Krzeminski Z. Nonlinear Control of InductionMotors. In Proceedings of 10th IFAC World

Congress, Munich, 1987; 349354.17. Mohan N. Electric Drive; An Integrative Approach,MNPERE: Minneapolis, 2000.

18. Mohan N. Advanced Electric Drives; Analysis,Control and Modeling using Simulink. MNPERE:Minneapolis, 2000.

MARIAN P. KAZMIERKOWSKI*

Institute of Control and Industrial Electronics

Warsaw University of Technology, Koszykowa 75

00-662 Warsaw, Poland

* Correspondence to: M.P. Kazmierkowski, Institute of Control and Industrial Electronics, Warsaw University ofTechnology, Koszykowa 75, 00-662 Warsaw, Poland.

Copyright # 2004 John Wiley & Sons, Ltd. Int. J. Robust Nonlinear Control2004; 14:767769

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