Scalar Controlled Three Phase Induction Motors using Variable Frequency Drives

摘要

This report is mainly concerned with the speed control of three phase induction motors (IMs) using variable frequency drive (VFD). Detailed study of conventional two levels, three-leg voltage source inverter (VSI) is adopted using pulse width modulation (PWM). The proposed control strategy adjusts theIM speed by changing both the voltage magnitude and frequency of the VSI. This approach is so-called "constant V/F" where the ratio of voltage magnitude and frequency is kept constant in order to maintain the magnetic flux which in turns keep fixed torque under varied speed conditions. A dedicated case study is introduced illustrating the mathematical modeling of induction motor and respective characteristics. The modeling of the proposed..