. Experimental evaluation, diagnosis, and prediction of the impacts of power quality disturbances in IE2, IE3, and IE4 class efficiency motors.

Abstract

Electric motors remain the largest end-use of electricity in the world and a fundamental part of the industrial sector. In addition, with technological advances, their applications have expanded into new categories such as electric vehicles, transportation, and navigation, among others. Europe has started to upgrade to IE4 efficiency motor classes, and it is expected that other regions will follow the transition to higher efficiency motor classes. In some regions, the operating voltage may differ from the nominal voltage according to IEC 60038-2009. This, together with other disturbances such as unbalance and voltage harmonics, can affect the performance of these new technologies. In this context, significant efforts have been made in predictive maintenance to improve existing techniques with new proposals that increase their effectiveness in diagnosing the health of rotating machines in the presence of different disturbances present in SEPs. This work evaluates the impact of voltage variations, voltage harmonics, and different percentages of under and over-voltage unbalances on the temperature and performance of low-power induction motors of IE2, IE3, and IE4 classes. The study includes technical, economic, statistical, and thermal analysis to obtain important indicators related to energy consumption, efficiency, power factor, and temperature. In the search for innovative and complementary techniques, this study also presents a new Electric Motor Degradation Indicator (EMDI) based on frequency domain analysis of electric motor current waveforms for the diagnosis of rotating machinery integrity. The results show that under ideal operating conditions, the permanent magnet motor of the IE4 class has a better performance in terms of power consumption and temperature, but it has a non-linear characteristic. Then, in the presence of certain disturbances, the scenario changes, with lower performance compared to squirrel-cage induction motors under the same operating conditions. The analysis performed will allow to identify and quantify the impact of the different perturbations present in the electrical power systems on the performance of the new electric motor technologies to be introduced. Regarding the proposed motor health diagnostic indicator, the results presented strongly support the effectiveness of the proposed approach in facilitating the implementation of predictive maintenance practices. Another important contribution of this thesis is that its results will form the basis for the implementation of a new regulation for the introduction of minimum efficiency requirements for electric motors in Honduras.