A New Approach to Energy Efficiency Evaluation of Induction Motor

The paper presents two important aspects of the energy efficiency evaluation of induction motors: the performance of a comparative analysis between the energy efficiency of an induction motor powered by two categories of sources - purely sinusoidal symmetrical three-phase source, respectively, frequency converter, and also, a new way of finding the energy efficiency of induction motors - in case of using frequency converters (and the existence of harmonics) - starting from the determination of the fractal dimension of the variation curves of the applied voltage, currents in the windings and the developed electromagnetic torque. The stated purpose is to show the influence of non-uniformity degree of the specific parameters of the induction motor, supplied by power electronics, on its energy efficiency - through a simple law - and to open the possibility of online evaluation of the energy efficiency in case of drive systems with continuously monitored induction motors. The entire study was carried out using PSIM and MATLAB software (to determine the fractal dimension).