CONTROLLER DESIGN FOR UNITY POWER FACTOR SUPPLY TO INDUCTION MOTOR DRIVE

Abstract

Induction motors are widely used in industry and agriculture pumps due to the fact that they are relatively cheap, rugged and maintenance free. However, they need reactive power for its operation. Thus, a large reactive power is required to be supplied and transmitted by the supply to the load. Inorder to improve efficiency of transmission lines as well as efficiency of induction motor, it is desired to improve the power factor by reducing the reactive power requirement. This can be done using upf controller which uses SPWM technique. In the present work, unity power factor on the supply side is obtained using sinusoidal pulse width modulation. Further, vector control for the control of speed of induction motor is used in the present study, which has widespread use in high performance induction motor drives. It allows, by means of a co-ordinate transformation, decoupling of the electromagnetic torque from the rotor flux. The decoupling control between the flux and torque allows induction motor to achieve fast transient response. Therefore, it is used in high performance motor applications. In the present work, an indirect vector control scheme is implimented with hysteresis current controller.