Simulação e ensaio de um motor de indução para obtenção de suas grandezas de modo comum e correntes de rolamento

Abstract

Induction motors driven by Pulse Width Modulation (PWM) inverters offer excellent performance but introduce significant challenges related to high-frequency phenomena. The rapid switching of semiconductor devices generates common-mode voltages and transient over voltages that excite intrinsic parasitic capacitances and induce high-frequency currents, negatively impacting component lifespan, especially bearings, through Electric Discharge Machining (EDM) currents. This work is dedicated to theoretical modeling, numerical simulation, and experimental validation of these phenomena, aiming to build a robust and precise equivalent circuit model for predicting and mitigating these issues. The developed methodology integrates lumped-element electrical modeling with detailed Finite Element Method (FEM) simulations. Parasitic capacitances (winding-to-frame, winding-to-rotor, and rotor-to-frame), stator winding and core impedance, and coil end inductance were characterized, explicitly considering the frequency dependence of these parameters, as well as skin and proximity effects. For current analysis, the Vector Fitting technique was employed for multi-frequency simulations of circulating currents, and a dynamic model was used for bearing EDM currents. The dissertation's main contribution lies in the rigorous validation of the proposed model through high-resolution experimental measurements, which confirmed the predictive capability of the approach in representing the machine's electromagnetic behavior and high-frequency current paths. The results obtained emphasize the necessity of considering these effects from the design and specification phases of inverter-fed motors. This study deepens the understanding of premature bearing failure mechanisms and provides a solid technical foundation for developing effective mitigation strategies, combining theoretical accuracy with practical validation.