Efficiency Evaluation of Induction Motors Supplied by VFDs

This paper presents an evaluation of the effects of variable frequency drives (VFDs) on induction machines efficiency. For this purpose, an experimental evaluation using international standards IEEE 112, IEC 60034-2-1 and IEC 60034-2-3 (draft version), was set up. These standards estimated the induction machine's efficiency based on a loss segregation approach to consider the stator, core, friction, rotor, stray-load, and additional losses contribution. Additionally, the machine's losses were studied using a time-stepping, 2D, Finite Element Method (FEM) analysis on the open-source software Gmsh-GetDP. This analysis used voltage waveforms suggested by IEC 60034-2-3 and a motor design with the same rated characteristics to those used in the experimental stage.