Exploring the MMF of a Three-Phase Induction Motor with Twelve-Zone Stator Windings

Currently, the main direction in increasing the energy efficiency of induction motor drive (IMD) is the implementation of control systems, which have the function of regulating technological processes in addition to reducing electricity consumption. However, about 70% of all induction motors (IM) are low and medium power motors being a part of uncontrolled electric drive systems. Therefore, significant savings of fuel and energy resources can be achieved only through the improvement of the energy efficiency of the induction motor itself. One of the most important areas for further improvement of the energy characteristics of the IM is the structure of the stator winding, which in turn will positively affect the conditions of electromechanical conversion. The principles of construction of asymmetric twelve-zone stator windings and possible variants of combination of separate sections are reviewed in the paper. A method for calculating the magnetomotive force (MMF) for a given connection scheme of individual coils of a stator winding and the values of phase currents is suggested. The suggested method for calculating the MMF is implemented in MATLAB. A decrease in the level of higher harmonics of MMF created by an asymmetric twelve-zone winding in comparison with a conventional stator winding design is substantiated, making it possible to predict an improvement in the operational characteristics of an IM with an asymmetric twelve-zone stator winding.