DEVELOPMENT OF AN ENERGY-EFFICIENT POWER SOURCE FOR THE POSITION OF NON-DISASSEMBLED VIBROACOUSTIC DIAGNOSTICS OF AN ELECTRIC ROLLING STOCK WITH A DC TRACTION MOTOR

ABSTRACT

Conducting experimental studies under operating conditions, transition to mathematical modeling of the wheel-motor unit of the electric rolling stock (EPS) at the position of in-place diagnostics of the bearings of the traction electric motor. Simulate a diagnostic complex that allows you to determine the technical condition of the wheel-motor unit in locomotive depots. An approach has been defined for selecting and evaluating the parameters of power sources at the position of in-place vibroacoustic diagnostics of the wheel-motor unit of the EPS in locomotive depots. The analysis of the methodology for designing semiconductor converters has been carried out. An algorithm for determining the state of bearings indiscriminately has been developed. The moment of inertia of the wheel pair connected to the anchor of the electric motor in the raised state of the electric rolling stock is determined. An experiment was carried out in the locomotive depot "Uzbekiston" JSC "Uzbekiston temir yullari" to determine the moment of inertia of the wheel-motor units.

АННОТАЦИЯ

Проведение экспериментальных исследований в условиях эксплуатации переход к математическому моделированию колесно-моторного блока электрического подвижного состава (ЭПС) при позиции безразборной диагностики подшипников тягового электрического двигателя. Моделировать диагностического комплекса, позволяющие определять техническое состояние колесно-моторного блока в локомотивных депо. Определён подход для выбора и оценки параметров источников питания при позиции безразборной виброакустической диагностики колесно-моторного блока ЭПС в локомотивных депо. Выполнен анализ методологии проектирования полупроводниковых преобразователей. Разработаны алгоритм определения состояния подшипников без разбора. Определён момент инерции колесной пары, соединенной с якорем электрического двигателя при поднятом состоянии электроподвижного состава. Проведён эксперимент в локомотивным депо «Узбекистон» АО «Узбекистон темир йуллари» для определения момент инерции колесно-моторных блоков.

Keywords: Electric rolling stock, power supply, traction electric motor, wheel-motor unit, vibroacoustic diagnostics, moment of inertia.

Ключевые слова: Электроподвижной состав, источник питания, тяговый электродвигатель, колесно-моторный блок, виброакустическая диагностика, момент инерции.

An analysis of equipment failures for electric locomotives on the railway network of the Republic of Uzbekistan shows that 25–35% of their total number are damage to traction motors (TED) [1–2].

The most important and vulnerable link of the EPS with DC traction motors is the bearings of the wheel-motor unit (KMB). The labor intensity of current, medium and major repairs of TED windings is from 30 to 70% of the total amount of work [1-2]. In turn, KMB bearings are the most reliable EPS element. During operation, defects occur with them;

Diagnostic complexes that determine the technical condition of the EPS in motion require special attention from specialists. For example, to determine the state of bearing assemblies by the intensity of infrared radiation when the train passes through specialized points using the KTSM diagnostic complex and places it on the stage. When EPS enters for maintenance or repair in a locomotive depot, the ARGUS complex is used to determine the state of the wheel pair rolling surface [7, 8].

To determine the state of bearing assemblies, their acoustic manifestations during rotation are used. In accordance with the rules for the repair of electrical machines, electric locomotives and electric trains must periodically undergo routine maintenance (TR-3) in a depot under collapsible conditions. This, as usual, takes a lot of time, labor, including energy costs due to the use of different stands [1-8].

Therefore, one of the most important tasks is to determine the method for detecting LCM defects in the CIP mode. In recent years, in the CIS countries, when repairing an EPS equipped with a KMB with collector engines, internal depot positions of vibroacoustic in-place diagnostics of traction electric drive anchor units began to be used [1-7].

The essence of the process of vibroacoustic diagnostics is as follows:

• an electric locomotive or a motor car is installed on a ditch equipped with jacks;
• then the diagnosed object is hung out on jacks and voltage is supplied to the power circuit from a special power source (PS), which is selected based on the results of several experiments carried out in the mathematical model, based on energy efficiency and reliability;
• upon reaching the required number of revolutions of the wheel pairs, with the help of special equipment, an assessment of the vibroacoustic manifestations of the anchor units is made and a conclusion is made about their condition.

It should be noted that the power required to drive the motors can be tens of kilowatts [1-8].

Improving the safety and reliability of train traffic is one of the priority tasks in Uzbekistan Temir Yollari JSC, which is inextricably linked with the overall performance and structural changes that are being implemented in railway transport. Figure 1 shows the number of identified bearing defects for the period 2019-2021.

Figure 1. Bearing defects for three years

In order to determine approaches for selecting and evaluating the parameters of power sources at the position of in-place vibroacoustic diagnostics of the KMB in the locomotive depot, an analysis of the methodology for designing semiconductor converters was performed.

When analyzing the technological process of in-place diagnostics of anchor nodes, it is required to justify the feasibility of using a portable mobile power source to determine sufficient power while simultaneously powering four TEMs [1-8].

Improvement of methods and tools for CIP bearing diagnostics of KMB is inextricably linked with the development of non-standard equipment for the implementation of the diagnostic process. You can imagine non-standard equipment with a modern controlled rectifier with transfer capabilities. To achieve this goal, a task is set that formulates the technical requirements for the power source of the position of vibroacoustic diagnostics, performing a quantitative analysis of the energy efficiency criteria for power source options [1-8].

Due to the laboriousness and cost of conducting experimental studies under operating conditions, the transition to mathematical modeling of the wheel-motor unit in the position of in-place diagnostics of TED bearings is a more optimal solution for the task. To determine an energy-efficient power supply as a load, the KMB mathematical model is used, described in the Matlab program in the Simulink package (Figure 2) [1-8].

Figure 2. KMB Model in Matlab/Simulink

In works [2-6], specialists considered the simulation of a switching power supply for carrying out the technological process of plasma-electrolytic oxidation, with the aim of building voltage-raising circuits; the pulse-width control circuit is synchronized with the supply network. Overview of modern static converters, various methods of frequency conversion with pulse-width modulation. Time diagrams of currents and voltages on the circuit elements were obtained when operating on an active load and an equivalent active-reactive equivalent circuit of the electrolyzer. A separate class of industrial consumers is singled out as requiring low-frequency power supply without its regulation, including dewaxing systems. Advantages and disadvantages relative to other types of frequency converters. The control voltage was received by a device, the main elements of which are two active pulse-width modulated converters connected by a common DC link. Recommendations are given for the construction of power sources for technological installations of plasma-electrolytic oxidation. A method of computer simulation has been obtained; experimental time dependences of electromagnetic processes and oscillograms are in qualitative agreement with each other and with theoretical data.

The power supplies discussed above are designed and calculated for different devices. The load value is important for conducting an experiment in the Matlab/Simulink environment to determine the energy efficiency of power supplies [2-6].

When modeling the KMB in the Matlab/Simulink environment, it is necessary to determine the values ​​of unknown parameters, such as the moment of inertia of the wheelset connected to the armature of the electric motor in the raised state of the ERS [2-6].

The moment of inertia in the wheel pair model connected to the electric motor armature is determined by the coast down method and the coefficient (1 + y) is calculated, taking into account the inertia of the rotating parts. To do this, in the depot during the experiment, the body is accelerated to a frequency slightly higher than the nominal one, then it is transferred to the run-down mode and the rotational speed of the electric motor n is measured at certain time intervals. As a result, it is possible to obtain a characteristic of the run-out time (T1) (Figure 3) [2-6]:

The characteristic allows you to determine the moment of inertia J of the rotating parts of the installation, kg m²:

where M_с is the moment of resistance of the motor armature, N m:

where Р_н is the rated power of the DC traction motor, W;

n_н - rated frequency of rotation of the electric motor, rpm.

Figure 3. Run-out time characteristic of a wheel pair connected to an electric motor armature

To determine the moment of inertia, it is necessary to take into account the diameter of the wheelset of an electric train and an electric locomotive (they are different) and perform an experiment for each pair.

The experiment was carried out in the locomotive depot "Uzbekiston" JSC "Uzbekiston temir yullari". In the mode of the technological position of the in-place vibroacoustic diagnostics of rolling bearings of the ERS of wheel pair rotation 150 rpm. According to the results of the experiment carried out several times, the average parameters of the moment of inertia were analyzed and determined (Table 1).

Table 1.

The average parameter of the moment of inertia of the EPS

 Conclusion

Based on the results produced in the locomotive depot "Uzbekiston" JSC "Uzbekiston temir yullari" for the development of an energy-efficient converter power supply, a mathematical model of the KMB was developed, which should be performed on the basis of the initial data obtained from the results of the experiments.

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