ISSN: 2319-5967 ISSN: 2319-5967 ISO 9001:2008 Certified International Journal of Engineering Science and Innovative Technology (IJESIT) Volume 2, Issue 2, March 2013 619 Performance Analysis of Fuzzy based DC Motor Drive Astha Tiwari, Dr. S. P. Dubey M.E. (Power Electronics) RCET, Bhilai, Professor & Dean RCET, Bhilai Abstract- This paper presents a simulation of speed control of a DC motor drive using fuzzy logic control at MATLAB environment. Separately excited DC motor is used and armature voltage control method is applied. Required control voltage based on motor speed error (e) and it changes (ce). The performance of DC motor drives system was evaluated through digital simulation using simulink toolbox of MATLAB. DC chopper is used as a diver in this work to change the average value of load voltage applied from a fixed DC source. To control average output voltage, pulse width modulation (PWM) technique is used. Fuzzy logic is used for defining membership function and rule for FLC. Fuzzy logic controller is able to cope with system uncertainty which is the disadvantage of traditional controller. Simulation result show that proposed controller gains optimal performance and wide range of speed control is possible by means of fuzzy logic controller. Index Terms: DC Motor, Fuzzy Logic, Speed Control. I. INTRODUCTION DC motors are widely used having good starting and breaking performance in such technologies as electric power drive automatic control system, such as, rolling mills mining machines and mine hoist machines. Because of their high reliabilities, flexibilities and low costs, DC motors are widely used in industrial applications, robot manipulators and home appliances where speed and position control of motor are required [1]. We are using armature voltage method, in the armature voltage control method, the voltage applied to the armature circuit; Va is varied without changing the voltage applied to the field circuit of the motor. Therefore, the motor must be separately excited to use armature voltage control. Because of the flexible control characteristics, separately excited d.c. motors or permanent magnet field d.c. motors are used in servo applications. In the past, the series motor was mainly used in traction. Presently, the separately exited motor is also employed in traction. The high starting torque was the main reason for using the series motor. However, the series motor has a number of limitations. The field of series motor cannot be easily controlled by static means. If field control is not employed, the series motor must be designed with its base speed equal to the highest desired speed of the drive. The higher base speeds are obtained using fewer terns in the field windings. However, this reduces the torque per ampere at zero and the low speed. Further, there are a number of problems with regenerative braking of series motor. On the other hand, regenerative braking of a separately exited motor is fairly simple and can be carried out down to very low speed. Because of the limitations of series motor, separately exited motors are now preferred even for traction applications. DC choppers used as a driver in this work change the average value of load voltage applied from a fixed DC source by switching a power switch such as thyristor, BJT. II. DRAWBACK OF CONVENTIONAL CONTROL METHOD The process equipment may not be available for experimentation, the procedure would usually be very costly, and for a large number of input values it is impractical to measure the output and interpolation between measured outputs would be required. The disadvantages are several: Linear techniques are valuable because they provide good insight. Besides, there exists no general theory for the analytic solution of nonlinear differential equations and consequently no comprehensive analysis tools for nonlinear dynamic systems. Two main problems encountered in motor control are the time-varying nature of motor parameters under operating conditions and existence of noise in system loop. Fuzzy control system is able to cope with system uncertainty. Fuzzy logic controller is chosen as a controller for this project because it consist several advantages. It provides parallel or distributed control, linguistic control, robust control, and It is suitable for application such as the speed control of dc motor which has non linearity. In this study FLC system design for operating at fixed speed under different load conditions are simulated at MATLAB/ Simulink environment.