Rectifier-inverter Converter Research Articles

Повышение эффективности электропривода электровоза с управляемым преобразователем возбуждения тяговых двигателей

Purpose: To substantiate the circuit design and algorithms for individual smooth and automatic control of single-phase direct current electric locomotives according to the laws of constant traction force and constant power without breaking the electric locomotive power circuits in order to increase the efficiency of its electric drive with controllable traction motor excitation converters. As a circuit design solution, it is proposed to apply a power electrical circuit with two rectifier-inverter converters for each section of the electric locomotive for bogie-based traction control, as well as individually controlled bridge transistor converters, shunting field windings, for axial traction control within each bogie. Methods: The development of circuit solutions using modern power semiconductor converters; theory of automatic control and design of finite state machines; mathematical modeling of electromagnetic, electromechanical and mechanical processes. Results: The developed control algorithms provide the possibility of obtaining traction characteristics of an electric locomotive that vary according to the laws of constancy of traction force or constancy of power, bringing the traction characteristics of electric locomotives with collector traction motors to the characteristics of electric locomotives with asynchronous traction motors. The calculations performed confirmed the possibility of implementing an algorithm for individual control of traction motor currents and their excitation currents, as well as traction forces, which ensures a smooth increase in the traction force of an electric locomotive.Practical significance: The developed technical solutions applicable in the manufacture of modern and modernization of operated electric locomotives will ensure an increase in the traction properties of singlephase DC electric locomotives and will contribute to an increase in the throughput and carrying capacity of the railway network.

Improving the Parameters of the Regenerative Braking Mode of the Thyristor Rectifier-inverter Converter by Addition the Diode-transistor Discharge Branch and New Operation Algorithm

Thyristor rectifier-inverter converters are widely used. The power factor of the standard converter of locomotives does not exceed 65% in this mode, which does not meet the requirements of the national standard for electric locomotives with collector traction motors. This fact is due to the need to turn on the thyristor in advance, in the wrong half-period, from the point of view of energy transfer to the electrical network. Such turning-on of the converter leads to a large amount of reactive energy transmitted to the electrical network by an electric locomotive. The purpose of this work is to compare the modes of the standard and new rectifier-inverter converters. The new rectifier-inverter converter in the recovery mode works with switching of the diode–thyristor branch and with a new algorithm of operation. Both the mathematical model of converters and physical models are investigated.

Improving maintenance system for controlled asynchronous electric drives of electric locomotives based on their diagnosis

The article assesses the reliability of improving the maintenance of the control system of an asynchronous traction electric drive of an electric rolling stock with a rectifier-inverter converter based on power IGBT transistors, increasing the power factor in traction mode and regenerative braking.

Влияние блока балластных резисторов на КПД электрической цепи электровоза переменного тока

In order to reduce electricity consumption when handling heavy freight trains, it is necessary to increase the performance characteristics of a regenerative braking mode of electric locomotives, the energy performance characteristics of which are currently unsatisfactory. In this article, the effect of the ballast resistor block on the efficiency indicator of the electric circuit of an alternating current electric locomotive is considered. The ballast resistor block is designed to ensure the static stability of the regenerative braking mode when organizing the inversion process of a thyristor rectifier-inverter converter with a constant margin angle δ = const. However, the use of ballast resistors in the anchor chain of traction electric engines negatively affects the energy performance characteristics of the electric locomotive in the regenerative braking mode. In order to eliminate this drawback, a method is proposed to ensure the stable operation of the regenerative braking mode without the block of ballast resistors of the alternating current electric locomotive with a rectifier-inverter converter based on IGBT transistors. The calculation of the efficiency performance characteristics of the electric circuit of an alternating current electric locomotive for the regenerative braking mode is presented both in the presence of the ballast resistor block in the power circuit and in the absence of it.

Рабочее диагностирование тиристорных плеч выпрямительно-инверторного преобразователя электровоза переменного тока

The article considers the principle of working diagnostics in real time of a rectifier-inverter converter of an AC electric locomotive in case of shoulder control failure. The proposed principle is based on the harmonic analysis of the rectified voltage curve and identification of the relative content of individual harmonics that are missing in normal mode. To increase reliability of detection of the damaged shoulders, it is proposed to use a diagnostic criterion based on assessment of changes in the resulting energy output of the converter at certain intervals of the mains voltage period. Due to the joint application of several criteria, damage detection with the necessary level of sensitivity is achieved. For each criterion, two groups of boundary values are calculated, due to which the selectivity of determining the failed shoulder is realized. The justification of the selected boundary conditions that distinguish the emergency mode from the normal one is presented. A simulation model has been created in the MatLAB Simulink software package, which allows exploring the possibilities of diagnosing a rectifier-inverter converter for various operating conditions. The results of simulation modeling confirming correctness of the proposed solutions are presented. It is indicated that the proposed diagnostic method should be used together with the alternative converter control algorithm that ensures operability of the electric part of the electric locomotive in case of failure of one of the arms.

Increasing the Efficiency of Recuperation Through the Use of Energy Storage Systems for the Own Needs of Traction Substations

The use of regenerative braking by electric rolling stock on DC railways makes it possible to increase the energy efficiency of the transportation process. The effective use of regenerative braking is associated with creation of conditions for receiving energy obtained through it. For these purposes, rectifier-inverter converters and energy absorbing devices are currently used in the traction power supply system.A promising technology that provides an increase in theefficiency of the use of regenerative braking is energy storage, which allows this energy to be used in the future to cover the traction load curve. A feature of the use of regenerative braking on singletrack sections of DC railways with low traffic intensity is the need to use converters or energy absorbing devices. One of the options for increasing the efficiency of recuperation energy use is the adoption of energy storage systems for the own needs of traction substations. The use of this technical solution is advisable on single-track sections with intensive use of regenerative braking, the effectiveness of which is explained through a decrease in power consumption for own needs of the substation from the external grid.The international research allows us to identify the widespread trend towards the application of electricity storage technology in various fields: from renewable energy sources to electric power systems, including transport power supply systems. International practices demonstrate successful implementation of pilot projects of adoption of energy storage systems for solving problems of increasing the efficiency of electric urban and suburban transport, as well as of metro systems.The objective of the work is to assess the energy performance of energy storage systems when using recovered energy for own needs of a traction substation. The study is based on the methods of mathematical and simulation modelling, optimisation, and mathematical statistics.The discussed issues refer to the use of energy storage systems to provide power supply for own needs of DC traction substations. Main issues of operation of storage systems are considered with the help of a substation case study. The features of the recuperation load curve are described to explain the use of hybrid technologies for developing a storage system. The example of the considered traction substation helps to demonstrate the solution to the problem of determining main parameters of the storage system, considering the specifics of operation of electrochemical and electrical modules.

Моделирование работы электровоза переменного тока в режиме рекуперативного торможения

Regenerative braking is one of the most important energy-saving resources on electric rolling stock (EPS) of railways and feasibility of its use is confirmed by a rich half-century history. The development of the recovery mode begins with the release of the experimental AC electric locomotive of the VL61 series № 012 and continues with the release of the modern series of electric locomotives 2 (3, 4) ES5K and EP1v/i. The use of recuperation allows you to achieve significant energy savings, to ensure the safety of driving heavy trains on the track profile with long descents. In the regenerative braking mode, the EPS has rigid braking characteristics, ensuring maintenance of constant train speed, increasing the technical speed of the train and capacity of the railway section. This article presents the results of mathematical modeling of operation of an AC electric locomotive in the regenerative braking mode using a standard rectifier-inverter converter (RIC) and presence of ballast resistor blocks (BRB) in the power circuit, and using a promising RIC based on IGBT transistors, for which a method for implementing regenerative braking on AC electric locomotives without the use of BRB in the anchor circuit of traction electric motors is developed, with the help of which it is possible to increase the amount of electricity given to the contact network, as well as to expand the area of braking characteristics of the electric locomotive.

Влияние плавного и ступенчатого регулирования ослабления возбуждения тяговых электродвигателей электровозов на скорость движения электроподвижного состава

ter reaching the maximum voltage at the 4th control zone of the rectifier-inverter converter of an AC electric locomotive, a further increase in speed is achieved by connecting the field attenuation system (FA) of traction electric motors (TEM). All domestic electric locomotives use the FA TEM system of the inductively active type with step switching. However, it has drawbacks, one of them is that step switching causes speed losses and slows down the acceleration of electric rolling stock (ERS). By 2025, the goal is to increase the speed of freight trains, which will increase freight turnover on the railway network [1]. One solution is to improve the ERS. In this regard, it is proposed to improve the standard FA TEM system of an electric locomotive by using IGBT transistors, which allow smooth regulation of the excitation current. In the article, using the graphical method of the RM, a curve of the train speed is constructed, which proves that the smooth control of the electric locomotive FA TEM allows you to quickly reach the maximum permissible speed of the electric locomotive on the section and to move at a higher speed in the ascent than with step-by-step regulation. The simulation of the 3ES5K series electric locomotive in the «Cortes» software complex on the Winter - Irkutsk-Sortirovochny section was also carried out, which proved that with the smooth regulation of the FA TEM, the technical speed of the ERS increases by at least 2,5 km/h.

Study of electromagnetic processes in the system “contact network—electric locomotive” while reducing the minimum opening angle of the thyristors in the rectifier-inverter converter

A new method is proposed for increasing the power factor of an electric locomotive by changing the minimum opening angle of thyristors α 0 of a rectifier-inverter converter. The decrease in the angle α 0 is due to changes in both the structure of the transducer and the zone of its regulation. A pulse synchronization device has been developed that makes it possible to generate pulses with strong distortions of the mains voltage U c at the points of natural transition of the voltage of the fundamental frequency U с through the zero line. Based on this device, an α 0 pulse-forming device was developed that eliminates the influence of pre- and post-switching voltage fluctuations. A “contact network—electric locomotive” model was created in the environment of MatLab/Simulink, taking into account the nonlinearity of the longitudinal parameters of the contact network. The effect of decreasing the angle α 0 on the character of pre- and post-switching voltage fluctuations was analyzed, and the parameters of transient processes were calculated. Particular attention was paid to modeling the parameters of traction network. The primary network parameters adopted in the model correspond to theoretical parameters for the selected type of contact suspension. Their high convergence is confirmed by the calculation of the coefficient of determination R 2. Calculations on the “contact network — electric locomotive” model show that compared with the standard scheme of the electric locomotive, where the minimum opening angle of the thyristors is α 0 = 9° el., the decrease in the angle α 0 to 4.5° el. leads to an almost twofold decrease in the amplitude of pre-switching voltage fluctuations and a small decrease in the amplitude of post-switching voltage fluctuations. The model results indicate that a decrease in the minimum thyristor opening angle α 0 leads to an increase in the power factor of the electric locomotive.

Energy efficiency assessment of the 3ES5K electric locomotives when using interval regulation technology in the form of "virtual coupling"

One of the promising ways to increase the capacity of railways is the way to reduce the interval between trains and its packet-mode handling. This method is implemented through the introduction of technology for interval regulation of train traffic. More advanced at present is the technology of interval regulation of train operation according to the "virtual coupling" type, which organizes the operation of trains with a minimum interval between them, which is safe for motion at and between stations. This technology removes the problem of extending the receiving and departure tracks, reduces peak loads on the traction power supply system and the formation time of the virtual coupling structure, and increases the train speed to the yellow traffic signal with safety guaranteed. The technology is implemented due to the presence of an interval control system for train operation, the introduction of on-board automatic locomotive signaling devices ALS-EN and ALS-R, on-board complexes BLOK and KLUB-U (safety devices with satellite navigation and electronic route map), ISAVP-RT-M (auto-driving system for coupled trains) and radio modems for data transmission. The use of these devices in packet mode traffic schedule will reduce the time interval along the sections of the railway and reduce the loss of time when the train runs to the yellow traffic signal. The set of tasks to increase the energy efficiency of applying the technology of interval regulation of train operation according to the "virtual coupling" type should also include the tasks of developing modern rectifier-inverter converters VIP-4000M on AC electric locomotives together with the reactive current block developed in the Railway Implementing Center of the Krasnoyarsk Railway. These developments provide a high power factor of the electric locomotive in the traction and regenerative braking modes (up to 0.96), which will reduce the specific electric energy consumption by electric locomotives for train traction, which will increase the efficiency of the application of the technology of interval regulation of train operation according to the "virtual coupling" type. In July 2019 pilot operational tests of this technology were carried out on the Far Eastern Railway, which showed generally positive results. The paper also presents an analysis of the results on the specific consumption of electric energy for traction and its return to the contact network during regenerative braking by 3ES5K electric locomotives participating in the technology of interval regulation of train operation of the "virtual coupling" type in the sections Khabarovsk-2-Ruzhino and Ruzhino-Khabarovsk-2 of the Far Eastern Railway. These results show an increase in the energy efficiency of electric locomotives using this technology.

Method of Increasing the Performance of Rectifier-Inverter Converters of Electric Transport in the Regenerative Braking Mode

Method of Increasing the Performance of Rectifier-Inverter Converters of Electric Transport in the Regenerative Braking Mode

Improving the energy performance of alternating-current electric vehicles

Russian Railways has taken an active position on the implementation of programs aimed at energy saving. The strategic priority of these programs is the development and introduction of new types of energy-efficient rolling stock, as well as modernization of existing and procurement of new locomotives with improved energy characteristics. After a long period of stagnation in the transport-engineering industry, railway- equipment manufacturers have started to use advanced resource-saving technologies. However, ac electric locomotives with rectifier–inverter converters and electrical locomotives with diode rectifiers equipped with a step-voltage regulator for the traction transformer are still used by Russian Railways. Despite the fact that starting and speed control of ac electric locomotives are carried out without losses in starting resistances, the increased consumption of reactive power and distortion of the form of current consumed from catenary system are a common problem for electric locomotives of this generation. The main methods and circuit design of reactive power regulators and selectors of current high harmonics and voltage in ac electric rolling stock, as well as the principle of operation and structure of the active and hybrid filters and power correctors, are considered in this article. Examples of various technical solutions providing active filtration of higher harmonics are given.

Analysis of electromagnetic processes in a homogeneous long line

Dependences between the currents and voltages at terminals of a homogeneous long line were analyzed. They make it possible to more correctly explain the changes in current and voltage in an electric-traction network when switching the thyristor arms of a rectifier–inverter converter than do conclusions obtained during replacement of a long line with a circuit with lumped parameters. An imitation model of the homogeneous low-loss long line in the MATLAB/Simulink software environment is proposed that adequately represents the propagation of incident and reflected electromagnetic waves along the line. Transfer functions are presented that approximate the frequency dependences of the specific parameters of the equivalent rail–ground loop and the overhead catenary–ground loop calculated taking into account the increase in the resistance of the wires due to the eddy currents and the surface effect. The influence of frequency dependences of the specific electric parameters of an electric-traction network calculated by various methods on the free voltage oscillation decay on the electric locomotive pantograph obtained by modeling the electromagnetic processes in the traction substation–electric traction network–electric locomotive system is revealed.