| There are various methods for speed control of induction motors. This paper specifically describes one of the methods: speed control using variable frequency. The proposed system is a MATLAB simulink model, which is a closed loop model designed to achieve desired speed control of a three-phase induction motor by varying its frequency. The simulink model has four main blocks, namely the inverter, synchronous machine, proportional integral control and current hysteresis control. For accuracy of output results and simplicity, we have used dq to abc transformation block and sin function block. The inverter is comprised of six integrated gate bipolar transistors (IGBTs), which are fired by gate pulses generated by current hysteresis control block. The inverter generates variable frequency and variable voltage output, which is given to motor terminals. The project presents the working principle of variable frequency drive (VFD), its performance, and the use of Pulse Width Modulation (PWM) in a three-phase inverter to control the frequency and thus the speed. The proposed method conformed to performance predictions and delivered the desired outputs. |
