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T. Lehtla. Power Electronics and Electrical Drives. TTU, Dept. of Electrical Drives andPower Electronics. Tallinn, 2003. 103 p.The textbook is completed by the support of EU Leonardo da Vinci program projectDevelopment of Engineering Curriculum for Remote Colleges of Technical Universities,CURENGCOL (EE/01/B/F/PP - 135 004).© T. Lehtla, 2003. tlehtla@cc.ttu.ee© TTU, Dept. of Electrical Drives and Power Electronics, 2003.Kopli 82, Tallinn, 10412Tel. 620 3700, 620 3702, 620 3704© Translation T. Lehtla, (Chapters 1, 2 and 3);M. Lehtla (Chapter 4) andR. Jansikene (Chapters 5 and 6)ISBN 9985-69-029-X2
PrefacePower electronics and electric drives are two fields of technology, very closely connected.Power electronics devices are the most advanced and effective switches of high power electriccircuits. Frequently, they are used as switches for the commutation of windings of electricmachines. The system which includes an electric machine, a power converter, based onsemiconductor switches, and several control devices is known as an electric drive. Todayabout 60 % of the electric energy produced will be converted and used by electric drives oftechnological machines.The flexible control of speed and torque of electric machines is possible due to modernmicroprocessor control and advanced power electronics devices. Optimal motion control oftechnological machines is a very urgent problem, the solution which will lead to higherproductivity of machines and essential energy saving.This textbook is intended for students of universities of applied sciences and remoteengineering colleges who study the courses of electronics. It is also useful for students ofother specialities, e.g. mechatronics or electric drives and power electronics. The book couldserve as a guide from the low power electrical world of micro-amps and milli-volts to the highpower world of kilo amps and kilo volts. By help of this book you may development anunderstanding that switching of power circuits is not only a logical operation, but also energyconversion. Every commutation in a power circuit will be accompanied with complex voltageand current transients.In contrast to the microchips that must be protected against static voltage charges and shortcircuitcurrents, power electronics devices must be protected against the commutation overvoltagesand over-temperatures.The turn-on or turn-off process in power circuits is not only a logic-level operation. The mainpurpose is the energy conversion. Consequently, power electronics operates in the field ofenergy conversion and control of energy flow in different technological equipment.Inappropriate operation of energy can cause not only malfunction or failure of equipment, butalso a major technological catastrophe. This is the through-going idea of this textbookElectric drives and motion control are the main application areas of power electronics devices,and the electromagnetic compatibility of power circuits is one of the most urgent problems inmodern power electronics. A flexible control of energy flow helps us to save energy and theenvironment and guarantee a sustainable global development.Tõnu Lehtla3
Page 1: Tallinn Technical UniversityDepartm
Page 5 and 6: INTRODUCTION1.1. Overview of electr
Page 7 and 8: Other processes of energy conversio
Page 9 and 10: contact switches. To guarantee effe
Page 11 and 12: drives includes a thyristor convert

power electronics and electrical drives - of / [www.ene.ttu.ee]

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