Microcontroller performance for DC motor speed control system

The electric drive systems used in industrial applications are increasingly required to meet higher performance and reliability requirements. The DC motor is an attractive piece of equipment in many industrial applications requiring variable speed and load characteristics due to its ease of controllability. Microcontrollers provide a suitable means of meeting these needs. Certainty, part of the recent activity on microcontrollers can be ascribed to their newness and challenge. In this paper, implementation of the MC68HC11E9 microcontroller for speed control of DC motor fed by a DC chopper has been investigated. 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. Experimental results have been obtained that show the employment of microcontroller for speed control and over current protection of a DC motor.