Control of DC Motor Using GSM Technology

Abstract

Electric drive systems used in many industrial applications require higher performance, reliability, and ability to vary the speed. One of the attractive features of the DC motor over all other types of motor is the relative ease with which speed control can be achieved. In this paper, speed control of DC motor using GSM technology has been investigated. It is a closed-loop real time control system, where the control circuit is coupled to the motor shaft to provide the feedback speed signal. A cell phone is attached to the control circuit which serves as a trigger. Pulse Width Modulation (PWM) technique is used, where its signal is generated in the microcontroller. The PWM signal will be send to motor driver to vary the voltage supply to motor. Controlling the PWM duty cycle is equivalent to controlling the motor terminal voltage, which in turn adjusts directly the motor speed, switch ON or switch OFF the motor supply. The microprocessors computes the actual speed of the motor by sensing the terminal voltage and the current, it then compares the actual speed of the motor with the reference speed and generates a suitable control signal which is fed into the triggering unit. This unit drives Power MOSFET amplifier, which in turn supplies a PWM voltage to the DC motor. Dual-tone multi-frequency (DTMF) signaling is used for telephone signaling over the line in the voice-frequency band to the call switching center