Estimação da Velocidade em Motores de Indução Trifásicos Via Análise do Espectro da Corrente

Abstract

Because it is robust, reliable and relatively low cost, the Three-Phase Induction Motor (MIT) is the main means of motive power used in industries, being used in a wide variety of industrial applications, from conveyor belts to machine tools. To increase the efficiency and consequently the useful life of three-phase induction motors, it is essential to employ some level of control, being essential the ability to measure their rotation speed, although in many cases this action is impractical due to the high cost of installing physical sensors at the end of the motor shaft or due to the difficult access location they are. This work proposes a simple and efficient method to estimate the rotation speed of MITs by analyzing the armature current signal spectrum. The collection of current signals under different load conditions and their subsequent analysis by the proposed method, resulted in an average percentage relative error of only 0.041% compared to the speed measured directly on the motor shaft. The proposed method is an efficient and viable alternative for estimating rotational speed in MITs in a non-invasive way, which can reduce costs and even be used online.