Lokesh kumar al. International Journal of Recent Research Aspects ISSN: 2349-7688, Vol. 1, Issue 3, December 2014, pp. 45-48 © 2014 IJRRA All Rights Reserved page - 45- Review and analysis Of Computational Technique on Speed Control of DC Motor Lokesh Kumar 1 , Dr. Kamal Sharma 2 , Himansu Gupta 3 1 Student, M. Tech, EMGOI, Ambala 2 Professor, Dept. of ECE, E-Max group of Institutions, Ambala 3 Assistant Professor, Dept. of EEE, E-Max group of Institutions, Ambala Abstract— The purpose was to achieve accurate trajectory control of the speed, specially when motor and load parameters are unknown It has been observed that one of the major challenges in speed control of dc motor is to reduce rise time as well as peak overshoot.introduced an artificial neural network based high performance speed control system for a dc motor. Performance of the identification and control algorithms was evaluated by simulating them on a typical dc motor model. Keywords- Membership function (MF) ), proportional–integral–derivative controller (PID), fuzzy logic controller(FLC) I. INTRODUCTION 1.1 GENERAL DC machines play an important role in industries and in our daily life. The outstanding advantage of DC machines is that they offer easily controllable characteristics. Their main disadvantage is high initial investment. In spite of this, DC machines still hold a strong competitive position for industrial applications because of their attractive features. Large DC motors are used in machine tools, printing press, conveyors, pumps, hoists cranes, paper mills and so forth. Small DC Machines (in fraction horse power rating) are used preliminary as control devices such as tacho-generators for speed sensing and servo motors for positioning and tracking. DC Motors still dominate traction motors used in transit cars and locomotives as torque speed characteristics of DC motors can be varied over a wide range while retaining high efficiency. DC Motors possess excellent torque-speed characteristics and offer a wide range of speed control. Though efforts are being made to obtain wide range speed control with AC motors, yet the versatility and flexibility of DC motor can't be matched by AC motors. Thus, the demand for DC motors would continue undiminished even in future. 1.2 CONSTRUCTION OF DC MOTOR The stator of dc motor has poles which are excited by dc current to produce magnetic field. The rotor has ring shaped laminated iron core with slots. Coils with several turns are placed in the slots. The distance between the two legs of the coil is about 180 electric degrees. The coils are connected in series. To keep the torque on dc motor from reversing every time the coil moves through the plane perpendicular to the magnetic fields, split ring device called a commutator, is used to reverse the current at that point. The commutator consists of insulated copper segments mounted in a cylinder. The electrical contacts to the rotating ring are called “brushes”. Modern motor normally use spring loaded carbon contacts. Two brushes are pressed to the commutators to permit current flow. The brushes are placed in neutral zone to reduce arcing. The stator of large DC machine consists of several poles. The interpoles reduce the field in to the neutral zone and eliminate the arcing of the commutator. A compensation winding is placed on the main poles to increase field during hard load. The iron core is supported by cast iron frame. The rotor iron core is mounted on the shaft. Coils are placed in the slots. A dc motor is rarely installed in a situation where it is required to run at a constant speed under constant load, since an AC induction motor performs such duties satisfactorily with cost only a fraction of price of DC machine of equal power and speed and requires minimum maintenance. Many simple speed variable systems are inherently stable in operation, so that steady state behavior of DC motor is frequently all that an engineer needs to take into consideration. For simple system a DC shunt motor excited from single source is often satisfactory and provides a reasonable range of adjustable speeds and torque. 1.3 Types of dc motor On the basis of excitation there are in general two types of dc motors:  Separately excited  Self-excited  Separately excited dc motor When the field winding of dc motor is connected to separate or external DC source motor is said to be separately excited dc motor. The voltage of external dc source has no relation with the armature voltage. 1.3.1 Self-exited dc motor When the field winding is excited by its own armature, motor is said to be self-exited DC motor. A self-exited DC motor can be sub divided into two forms. Shunt dc motor: In this type of motor, field winding is connected in parallel or in shunt with the armature. Therefore the voltage across armature terminal and shunt field is same. Series DC motor: In this type of motor, the field winding is connected in series with armature. Therefore field current depends on the armature current. 1.4 Principle Of Operation In any electric motor, operation is based on simple electromagnetism. A current carrying conductor generates a