Simplified stability analysis of a three-phase induction motor drive system

Stability analysis is one of the most important aspects to determine the performance of electric drive system during dynamic and steady state operating conditions. This is especially important since the motor operates in wide range of frequencies with the complex types of control strategies such as field oriented control and direct torque control. A new dynamic model is developed to study the instantaneous effect of varying voltage/current. In addition small signal equations are developed to evaluate the control performance by using conventional techniques such as Bode plot, Nyquist plot etc. In practice voltage-current relationships are used to perform such study. In this paper, the dynamic model based on voltage-flux-linkage relationship is utilized to evaluate the control performance of the three phase induction motor drive system. The presented model offers advantage of simplified analysis and provides more meaningful information. A study of voltage-current model and voltage-flux-linkage model has been carried out in this paper and important inferences are drawn from it. Analytical and simulation approach is used in the paper.