الفهرس 
History of De DrivesOnly 14 pages are availabe for public view
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Abstract
The use of adjustable speed dc motor drives is used in industrial utility and
many processes. The versatile control of characteristics of dc motors have
contributed to their extensive use in industry.
This Thesis presents the design and testing of a microprocessor controlled
separately excited dc motor supplied from a PWM GTO-thyristor converter. The
three-phase GTO thyristor converter employing PWM scheme has been found to
offer better overall performance than the phase control. The motor speed is
controlled by adjusting the armature voltage by PWM GTO thyristor converter.
The closed loop system for speed control of dc motors is designed and tested by
using three-series loops techniques for the speed and current control.
The Thesis contains seven Chapters as follows:
Chapter one contains an introduction to the history of de drives and the
different types of converters. Chapter two discusses the features of GTO thyristor
and different types of its gate drive circuits. The indirect gate drive circuit for
wide frequency range application, used in this work, is explained in details.
In Chapter three, the bridge converter is discussed. The one-quadrant sixGTO
thyristor bridge converter and its protections are explained in details. The
different types of PWM schemes for the converter is discussed. The EPWM
scheme, used in this work, is explained in details.
In Chapter four, converter-de motor drive system is designed and tested,
where the speed control of the system has been achieved by using 8088
microprocessor control. A software program was developed to generate the ontime
periods of the converter in the proper sequence, which is synchronized with
the supply frequency. The torque and speed characteristics of the motor are
simulated at different on-time periods and different loading conditions.Chapter five presents a mathematical analysis for the converter-de motor
drive system and the performance of the drive system has been studied for
continuous and discontinuous armature current operations.
In Chapter six, the closed loop control system is studied and designed. The
three series loops techniques are used for implementing speed and current
controllers, which give good performance for the speed control of the de motor
drive system. The details of the required software and hardware for the closed
loop control system are described. The improvement of the motor transient
performance in the closed loop operation is clearly shown from the experimental
results.
The conclusions are introduced in Chapter seven.