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This article describes the standard field reduction system of traction electric motors of a contactor-resistors type using inductive shunts, its drawbacks are revealed. An improved field reduction system of traction electric motors of an AC locomotive based on IGBT transistors has been developed and proposed. The proposed solution will allow to exclude the copper-containing inductive shunt from the power circuit, while providing reliable protection in non-stationary operating modes of the electric locomotive, as well as reduce electricity consumption for train traction. To prove the advantages of the proposed the field reduction system of traction electric motors, a method of comparative analysis of electromagnetic processes of the mathematical model of the standard and proposed systems of the field reduction of traction electric motors of an electric locomotive obtained in the MatLab Simulink environment was applied. As a result, it is proved that the implementation of the field reduction systems of traction electric motors using IGBT transistors with the developed control algorithm provides an increase in the power factor of an electric locomotive on average by at least 4%, and also significantly reduces the ripple current of the traction electric motor.

In this article, the authors have studied the electromagnetic processes of an inverter based on thyristors and IGBT transistors of an AC electric train in the regenerative braking mode. To accomplish this task, a method was used to compose instantaneous replacement schemes and systems of differential equations corresponding to a certain time interval of the rectified voltage diagram and the currents of the inverter arms. On the basis of the study were given the disadvantages of thyristor inverter and the advantages of transistor.

An urgent issue is to increase the power factor of electric rolling stock. One of the ways to increase the power factor in the traction and regenerative braking modes was proposed by the scientists of IrGUPS - this is the use of a rectifier-inverter converter on IGBT with modified control algorithms. This solution allows to significantly reduce the consumption of reactive current from the contact network, increase the capacity of railway sections, increase the technical speed, increase the efficiency of the traction power supply system, and also increase the amount of electricity returned to the contact network in the regenerative braking mode. The study of the performance of this converter is of interest. The transported volumes of goods on the railway lines of the Russian Federation continue to increase. One of the key links in ensuring the specified growth rates of tonne-kilometer work is the availability of powerful traction rolling stock equipped with an appropriate traction drive. A powerful traction drive is characterized by the consumption of significant current. To ensure its flow over the arms of the converter, a parallel connection of power semiconductor devices is used. For modern converters of electric locomotives, 4 parallel branches of power switches are used in the arm. The features of the parallel operation of the arm branches affect the performance of the converter on IGBT transistors. This article proposes to consider one of these features, namely the influence of parasitic inductances on the distribution of currents in the parallel branches of the converter, depending on the connection point of the AC power bus. The study was carried out using the Matlab Simulink software package. The article discusses various options for the topology of connecting power buses and presents diagrams of the distribution of currents in the parallel branches of the arm for each connection method. An assessment was made of such parameters as the spread of the peak current of switching on the branches of the arm, the time of current equalization during the conduction period, and the difference in the magnitude of the current in specific branches. Based on the results of the study, as well as taking into account the existing dimensions for the equipment of AC electric locomotives, a conclusion was made about the most optimal option for connecting power buses.

The paper deals with benefits of a new rectifier-inverter converter of an electric locomotive based on IGBT-transistors. Main directions of heavy haul traffic's development are considered for Siberia and Russian Far East electrified railways. Throughput and carrying capacity of power supply devices extremely depends on the voltage level in the catenary network of electrified sections of railways. Objects of our research are electric parameters of the 25 kV, 50 Hz AC traction power supply system. Operation parameters of two different types of the electric locomotive’s rectifier-inverter converters are calculated and discussed. We investigated operation parameters for thyristor-based and IGBT-transistors- based rectifier-inverter converter. Current and voltage curves for the thyristor and the transistor type of the rectifier-inverter converter are given and discussed. Similarity factor of current curves for electric locomotives was calculated by equivalent sinusoid’s .method. Quantitative assessment of the voltage level, currents and voltage losses in the AC catenary network is given. The graph-analytical method was used for constructing currents and voltages vector diagrams. It is proved that electric locomotives with a new rectifier-inverter conversion based on IGBT transistors provides a reducing of the total voltage losses in three times in the traction network comparing the thyristor conversion's operation.