Özet:

The electric drive with a squirrel-caged induction motor working in frequent start-stop modes is the object of this study. These drives have wide applications nowadays, such as in electric vehicles and hybrid electric vehicles, so improvement of their efficiency during the transients is an important task today. The one of the problems of such drives lays in the high energy consumption during the transients, especially if we talk about the acceleration of the motor. Due to the high starting currents large amount of consumed energy is dispersed as heat on the motor windings. The experimental studies carried out in this work have proved the necessity of limitations of these currents. However, such a decision will lead to the increase of the motor acceleration period which means that the starting currents, even having lesser magnitude, will last longer. This consequence will, therefore, also cause higher energy losses. So, there should be a point of the optimum – the acceleration period, during which the electric drive consumes the least possible energy. In order to determine the optimal acceleration period, the computer model of the electric drive with a squirrel-caged induction motor, controlled by a smooth start device, was developed in this paper. The smooth start device provides the possibility of evenly increasing of the voltage from zero to the rated value. The research has proven the existence of the optimal voltage increasing period, during which the motor acceleration heat losses are minimal. This optimal point depends only on the motor-drive system parameters and remains consistent for any applied load. The research results provide the possibility of improving the efficiency of the electric drives working in frequent start-stop modes due to a slight increasing of the motor acceleration period that leads to the reduction of the starting currents. Author Biographies Mykola Ostroverkhov, National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», 37, Peremohy ave., Kyiv, Ukraine, 03056 Doctor of Technical Sciences, Professor, Head of DepartmentDepartment of Theoretical Electrical Engineering

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