Abstract—Single phase induction motor has been used widely in discipline industry and household where a simple motor starter can't let vary speed in starting and also running with mechanical load. This paper introduces a method for controlling the speed of an AC single phase induction motor. Combination of micro controller unit & TRIAC has been used. A single phase induction motor adjustable speed control is implemented with hardware setup and software program. The main feature used in PIC17C756 microcontroller to control speed is pulse width modulation technique. Voltage drop across two terminals of TRIAC MT1 and MT2 is controlled with its gate voltage. Gate is controlled by DIAC and its input is controlled by an R-C triggering circuit. In triggering circuit variable resistor is used to vary TRIAC gate voltage through DIAC. DIAC gate voltage, TRIAC input voltage and output voltage are also simulated by “Electronic Workbench” software. One chip and re-programmable ROM avoids nonlinearity and it can replace mechanical speed variation. Output voltage and capacity of the system can also be varied.

Index Terms—Pulse width modulation, micro controller unit,triode for alternating current, diode for alternating current,silicon controlled rectifier, metal oxide semiconductor field effect transistor

The authors are with with Islamic University of Technology,Bangladesh. (e-mail: riasatkhan87@hotmail.com; e-mail:mdriyadhsharif@gmail.com).

Cite: R.Khan and M.M.S. Riyadh, "PWM Speed Control of AC Single Phase Induction Motor Using MCU Series Combined With TRIAC Technology," International Journal of Computer and Electrical Engineering vol. 3, no. 6, pp. 865-868, 2011.