Synchronous Current Control of Three phase Induction motor by CEMF compensation

Abstract

The performance of the machine largely depends on quality of applied current control strategy. Hysteresis-band PWM current control is one of the methods whose task is to force the actual current to track reference wave by means of switches. In low speed region of the machine, when CEMF is low, there is no difficulty in current controller tracking. However at higher speed, the current controller will saturate in part of the cycle due to higher CEMF and will be less and its phase will lag with respect to command current. PWM frequency is not constant (varies within a band) and as a result non-optimum harmonic ripple is generated in machine current. Fundamental current suffers a phase lag which increases at higher frequency. This phase deviation causes problems in high performance machine control. Synchronous Current Control is implemented using MATLAB/SIMULINK