Bacterial Foraging Algorithm application for induction motor field efficiency estimation under harmonics and unbalanced voltages

The time harmonic flow in industrial electrical grids with voltage deviations and unbalance, significantly affects three phase induction motor operation and makes difficult energy characterization. There are different methods for in situ estimation of motors efficiency. However, none of them have been sufficiently precise for the analysis under non-sinusoidal, deviated and unbalanced voltage conditions. This paper presents a method based on the equivalent circuits, with losses segregation and using Bacterial Foraging Algorithm (BFA). It allows determining under field conditions and low invasiveness, energy efficiency of induction motors operating under the before mentioned conditions. This method was tested successfully on a 0.55 kW motor, fed with significant levels of unbalance and voltage harmonics.