A Flexible Closed Loop PMDC Motor Speed Control System for Precise Positioning

The speed control of DC motor is very significant especially in applications where precision is of great importance. Due to its ease of controllability the DC motor is used in many industrial applications requiring variable speed and load characteristics. So the precise speed control of a DC motor is very crucial in industry. In this case microcontrollers play a vital role for the flexible control of DC motors. This current research work investigates the implementation of an ATmega8L microcontroller for the speed control of DC motor fed by a DC chopper. The chopper is driven by a high frequency PWM signal. Controlling the PWM duty cycle is equivalent to controlling the motor terminal voltage, which in turn adjusts directly the motor speed. H-bridge circuit is implemented for the bi-directional control of the motor. A prototype of permanent magnet DC motor speed control system using the microcontroller is developed and tested