Use of frequency converters in the stator circuit of a doubly-fed induction motor of a hoisting unit

Abstract

Abstract One of the currently accepted options for modernizing an induction electric drive is the use of a frequency motor control. In this case, a frequency converter is connected to the motor stator with the ability to control the voltage parameters at its output. Usually, frequency control is applied to induction squirrel-cage motors, including special machines designed for frequency control. In this case, as a rule, the frequency changes “down” from the nominal frequency of the voltage on the stator of the machine, and the speed control range is determined by the minimum frequency of the voltage applied to the stator. At the same time, for motors used in the electric drive of hoisting installations, the speed control range is limited to 2:1 due to the deterioration of the properties of the magnetic system of the machine. Speed regulation below half the rated speed can be carried out using a controlled rotor current converter.