Modelling and simulation of unsymmetrical supplied three-phase induction motor

A general mathematical model of a three-phase symmetrical induction motor expressed by means of state equations with line-to-line voltages as input variables is presented. Such a model permits the analysis of the dynamic behaviour of the motor supplied with unsymmetrical sinusoidal or non-sinusoidal voltage wave-forms. Simulation programs were written by means of MATLAB/Simulink software package. The presented model was used to simulate transient behaviour of the motor with unsymmetrical supplied voltages and its operation when fed from a symmetrical source (the mains) and from a six-step inverter. A mathematical model representing the induction motor operated with one phase disconnected was developed and simulated. Experimental results were compared with the simulated ones and good resemblance was observed.