Reactive Power of Asynchronous Electric Drives with Semiconductor Converters

Abstract

The purpose of the article is to obtain a ratio for determining the reactive power of induction motors when powered by semiconductor converters. The task is to determine the dependence of reactive power on control parameters of the converters. The research method used is computer simulation of electric drive based on Fryze power theory for non-sinusoidal currents. The result is the obtained expression for the calculation of reactive power, which takes into account the rated idle current of the motor with sinusoidal power supply and the type of converter, due to introducing special coefficients. Numerical values of the latter, depending on the control parameter, are obtained on computer models with their subsequent approximation. The scientific novelty of the research is in the further development of Fryze power theory in the direction of decomposition of non-sinusoidal current components using computer models. The practical significance is the obtained expression for determining the reactive power of an asynchronous electric drive with a thyristor voltage converter, on the basis of which the capacity of compensating capacitors is calculated to increase its energy efficiency.

The Evaluation of Electric Power by Separate Analysis of Fourier Transform Components

“…The problem of accurate active and reactive power evaluation remains pretty actual for many practical issues existing in electrical engineering. Mentioned problem has a significant importance, for example, in technical applications which regard the control and monitoring of the electrical energy [1][2][3][4], the analysis of technical performance of asynchronous electric drivers with semiconductor converters [5] and also, taking into account that the deterioration of electrical insulation is accompanied by the increasing of the dependent on dissipated in dielectric material active power dissipation factor [6], for problems which are inextricably linked with the assessment of quality of the electrical insulation [7,8].…”