Steady State Analytical Study of Stator Current Harmonic Spectrum Components on Three-Phase Induction Motor under Unbalanced Supply Voltage

Almost all induction motor applications suffer from unbalanced supply voltage. Under such conditions the motor operation can be seriously affected. Performance, control and monitoring are directly connected to the knowledge of the supply harmonics effects on the motor. Therefore there is a real need to derive a general mathematical formula predicting the harmonics growth in one hand, and to describe, through an analytical analysis in steady state operation the impact of unbalanced voltage supply on induction machine in the other hand. In this paper, an original analytical formula of harmonics components is developed to propose an accurate indicator of unbalanced supply voltage fault. The validity of this analytical study is confirmed by a comparison with simulation and experimental results.