Low frequency stability study of a three-phase induction motor

A suitable volt/Hz control strategy is proposed for stability improvement in low frequency operation of induction motors fed from variable voltage and variable frequency supply. The analysis based on small scale perturbation method applied to the linearized model of state-space equations. Stability analyses are carried out through evaluation of eigen values of the linear model characteristic equation. Stability investigation shows that the simultaneous adjustment of stator voltage and frequency provides a convenient means for maintaining stability of induction motor. The results are verified by standard transient analysis method and demonstrate a very close agreement.