Design and Development of V/F Controlled Induction Motor Drive

Abstract

The V/f control method is one of speed control methods for induction motors. In V/f control methods, the stator voltage is adjusted in a part of the supply frequency, except for low and above base speeds. At low frequency operation the voltage drop across stator resistance must be taken into account. The boost voltage is required to compensate the voltage drop across the stator resistance. The speed of induction motor is controlled by varying frequency and amplitude of stator voltage simultaneously, keeping ratio of V/f constant. The V/f control scheme maintains actual speed of motor to that of reference speed. There are two implementation methods: open loop scheme and close loop scheme. Simulation of close loop control of V/f controlled induction motor drive is carried out to obtain wide range of speed control at constant maximum torque. The objective is to develop a model to implement V/f control of an induction motor.