STATIC CHARACTERISTICS OF A CONTROLLED ELECTRIC DRIVE IN DYNAMIC BRAKING MODE

Abstract

This paper is devoted to the study of controlled electric drives of direct and alternating current operating in the dynamic braking mode using high-frequency pulse converters. Increasing requirements for energy efficiency, reliability, and controllability of industrial electric drives necessitate an in-depth analysis of the processes occurring in the power circuit during braking, as well as an assessment of the influence of discontinuous and continuous current modes on static and mechanical characteristics. The aim of the research is to substantiate the parameters of the power part of a controlled electric drive and to determine the boundaries of the stable operating range of pulse converters in the dynamic braking mode. To achieve this goal, circuit solutions were analyzed, simulation models were developed, static and mechanical characteristics were investigated, and boundary duty cycle values of pulse converters were determined. Using analytical methods and simulation modeling in the MATLAB–Simulink environment, families of static and mechanical characteristics for electric drives of various power ratings were obtained. It was established that with increasing motor power, the region of discontinuous current operation significantly decreases, while the continuous current region expands. Boundary duty cycle values corresponding to the transition between current modes were determined, and it was shown that these values weakly depend on the armature time constant and are mainly governed by the back electromotive force. The obtained results confirm the proposed hypothesis and contribute to the development of scientific knowledge on controlled dynamic braking modes of electric drives. The practical significance of the study lies in the applicability of the results to the design and tuning of automatic control systems for industrial electric drives.