Modelling and computer simulation of induction machine

The dynamic modelling of induction machines involves the development of accurate and reliable models that can adequately account for the machine’s non-linearities. The work presents the modelling of the Squirrel-cage rotor bar. To effectively account for Skin-effect in the rotor bar, a T-network lumped parameter model is developed. An optimisation algorithm which provides a good correlation between the actual bar impedance and the model impedance for varying frequency at approximately 6% error is achieved. MATLAB Programs are developed and used to solve the steady and transient mathematical models of the machine. A comparison between the predicted transient torque and speed in the conventional model and that with Skin or/and Saturation effects shows a remarkable difference. The simulated machine model with both skin-effect and saturation effect included gives a better result. The study also investigates the estimation of induction machine mean temperatures at different parts. It is observed that the computed mean temperatures of the machine parts at No-load, rated load and blocked rotor operations compare satisfactorily well with the measured temperatures.