The Induction Machine Operating from a Voltage Supply, Unbalanced and Polluted with Harmonics: A Practical Approach

In this paper the authors applied analytical, and experimental procedures for investigating the operation of the three-phase induction motor (IM) energized from an unbalanced voltage supply and in the presence of harmonics. The main direction of investigation focuses on motor performance. The analytical model of the IM includes the effects of the voltage unbalance through the presence of positive and negative sequence parameters, as well as the effects of harmonics. The model takes into account the skin effect due to the presence of the higher frequency harmonics. The overall procedure proven to deliver a complete mapping of the IM operation, including the calculation of the unbalanced current, all categories of loss, developed torque, as well as the assessment of the harmonic effects. The final result of the work becomes useful in regards to IM rerating for the reason of preserving its lifespan.