Single-phase induction motors are widely used in home appliances and industrial control. The multispeed operation and multipurpose operation are provided by controlling the speed of these motors.
This project includes building a variable speed drive of single phase induction motor using frequency control method. It is to develop the solid state control system to be reliable and economically feasible to use with fractional horse power motors. The proposed variable speed drive includes power conversion sections (AC to DC using power Diode Bridge and DC to AC using H-bridge). Through using a suitable Pulse width Modulation technique, the H-Bridge can generate two variable frequency and variable amplitude AC waveforms which are 90 degrees phase shifted supplied to both the main and auxiliary windings of the single phase induction motors allowing the rated torque to be achieved from the motor at any speed with the motor operating at a small slip. The control of the H-bridge is done using a microcontroller.