Stability Analysis of a Five Phase Closed Loop Induction Motor Drive System Using D - partition Technique

This paper deals with the stability analysis of a five phase induction motor drive system which operates in closed loop constant v/f control mode. A very old and efficient technique called d-partition technique or parameter plane technique is utilized to determine the stability of a five phase induction motor drive. This is a very powerful technique which not only determines the relative stability of the system but also enables to find out the drive parameter values for which fastest transient response can be obtained. Using d-partition technique variation of inverter time constant (Tin) and gain (K) is made to determine the effect of stability on the induction motor drive system at a different values of voltage and frequency keeping v/f ratio constant. Different graphs are plotted in terms of parameters of the drives and relative idea of degree of stability is obtained. PI controller can also be designed for variable frequency operation and maximum stability and minimum settling time. This stability analysis of the drive is helpful for the determination of the relative stability of the induction motor drive with which fastest transient response can be obtained. Using d-partition technique stability analysis of the induction motor drive is carried out with the help of Matlab codes.