This research is design and construct of Sine Pulse Width Modulation (SPWM) 4-leg voltage source inverter for controlling speed of asymmetrical two-phase induction motor. The Sine PWM switching signal is generated by ARM7 (Adu7024) microcontroller which is programmable and cheap, while having high frequency to generating switching signal. Two ICs No. IR2130 are used for motor driving part. The characteristics of output current signal are nearly closed to sinusoidal pattern resulting to high efficiency for motor control. In order to control the speed of induction motor, ratios of voltage to frequency (V/f) are controlled and constant torques are obtained by implementing technique of PI close-loop control.