Stability Analysis of a Rectifier-Inverter Induction Motor Drive

A stability study of a rectifier-inverter induction motor drive system is performed by neglecting the harmonic content of the stator voltages and applying Nyquist stability criterion to the small- displacement equations obtained by linearization about an operating point. This investigation reveals that system instability can occur over a wide speed range if the system parameters are improperly selected. It appears that the method of analysis presented in this paper is sufficient to predict stability of practical rectifier-inverter induction motor drive systems. Also, with slight modifications, this method of analysis can be applied to rectifier-inverter systems which supply reluctance-synchronous machines or synchronous machines.