Modelling and Steady State Performance of Dual Winding Induction Motor

Abstract

Dual winding induction motors have aroused quite a lot of interest and controversy over the past years. The question of whether dual winding induction motors have improved performance characteristics over their single winding counterpart has yielded varying answers. In this research work, the equivalent circuit of the dual winding induction motor for steadystate operation is obtained through standard induction motor analysis methods. The equations derived are used to simulate the motor performance in MATLAB/Simulink environment and comparison is made between the dual winding induction motor and an equivalent single winding induction motor. The simulation results are presented and discussed. The results of the study show that the dual winding induction motor has a higher starting current than that of the single winding equivalent which is unattractive considering that high starting current is one of the drawbacks of the conventional motors. The high starting current is however responsible for the rather impressive starting torque in the dual winding induction motor which is desired. The starting and maximum torque of the dual winding motor are 18.4Nm and 36Nm respectively which is an improvement over those of the single winding motor (3.2Nm and 12.1Nm respectively). There is a marked improvement in other performance characteristics of the motor under study. The power factor is at 0.9 compared to 0.7 of the single winding motor and the efficiency of the motor also improved from 78% for the single winding motor to 88% of the dual winding induction motor. This shows a 12.8% improvement in motor efficiency, and translates to reduction in energy demand by this motor