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MOTOR
1Berdiev Usan Turdievich, 1Khasanov Fozil Farhod ogli, 1Kutbidinov Odiljon Mukhammadjon ogli, 2Norboev Anvar Eshmuminovich
1Tashkent state transport university, 2Karshi engineering economics institute
Abstract: This article covers at one of the high-priority areas for auxiliary electric drives using asynchronous electric motors controlled by a three-phase autonomous voltage inverter. Various auxiliary electrical equipment is used to ensure the optimal use of electrical energy supplied by the power supply system and the safe movement of rolling stock. Carry out technical and organizational actions linked to energy saving and rational energy usage to ensure the normal and trouble-free functioning of auxiliary electrical equipment.
Key words: Train traction, converting, drive, regulatory problems, contact network, dissymmetrical, devices and systems, functional, fan motor
UCH FAZALI AVTONOM VOLTAJLI INVERTERDAN ASENCHRON MOTOR BO'LGAN YORQIMCHI ELEKTR CHAYVAN
1Berdiev Usan Turdievich, 1Hasanov Fozil Farhod o'g'li, 1Kutbidinov Odiljon Muhammadjon o'g'li, 2Norboyev Anvar Eshmuminovich
1Toshkent davlat transport universiteti, 2Qarshi muhandislik-iqtisodiyoti instituti
Annotatsiya: ushbu maqola uch fazali avtonom kuchlanish inverteri tomonidan boshqariladigan asenkron elektr motorlaridan foydalangan holda yordamchi elektr drayvlar uchun ustuvoryo'nalishlardan birini qamrab oladi. Elektr ta'minoti tizimi tomonidan ta'minlangan elektr energiyasidan optimal foydalanish va harakatlanuvchi tarkibning xavfsiz harakatlanishini ta'minlash uchun turli xil yordamchi elektr jihozlari qo'llaniladi. Yordamchi elektr jihozlarining normal va muammosiz ishlashini ta'minlash uchun energiyani tejash va energiyadan oqilona foydalanish bilan bog'liq texnik va tashkiliy tadbirlarni amalga oshirish. Kalit so'zlar: poyezdni tortish, konvertatsiya qilish, boshqarish, tartibga solish muammolari, kontakt tarmog'i, nosimmetrik, qurilmalar va tizimlar, funktsional, fan motori
Results. The most promising technical solution in the field of auxiliary ED ERS can be considered today as the organization of power supply for three-phase AD from a three-phase AVI. In this case, it is possible to obtain a symmetrical three-phase supply voltage stabilized in magnitude on the AD stator, the frequency of which is adjustable, providing a variable performance of motor-fans, as well as the formation of starting and braking modes of motor-compressors. Thanks to the noted properties, it is possible to achieve a high use of the installed power of the AD, there is no need to overestimate it in case of a decrease in the supply voltage, the current operating modes are optimized by eliminating current surges during start-up and
switching. The disadvantage when powered from the AVI is the additional losses in the AD from the higher time harmonics of the current, as well as losses in the AVI circuit. Static converters of modern FCED, including those used to power three-phase AD in the auxiliary ED of the ERS, have a high efficiency (about 95% in nominal mode) [7-10], and also make it possible to obtain the efficiency of the supplied AD close to the nominal one.
Conclusion. Actual tasks in the development of new and analysis of processes in existing systems of auxiliary ED based on FCED with AVI and AD are, including in terms of energy efficiency: -ensuring electromagnetic compatibility of the frequency-controlled asynchronous ED;
- selection of optimal AD start-up modes;
- issues of reactive power compensation.
Completion of these tasks can be achieved by improving the quality of development and operation of an auxiliary electric drive of electric locomotives by creating calculation methods, studying with their help the performance and quality of operation of auxiliary electric drive circuits in various modes.
Methods. Statistical analyzes were used to analyze asynchronous machines powered by a three-phase voltage antonym inverter.
Introduction
Auxiliary circuits of electric rolling stock (ERS) are electric machines and devices that provide cooling of traction drive electrical equipment, supply of compressed air to the pneumatic braking system of the train, power supply of control circuits, creation of the necessary comfortable conditions in the driver's cab and passenger cars [1-3]. Auxiliary electrical equipment is divided into power converters, electrical machines and control systems.
The conversion of alternating current with a frequency of 50 Hz into an electric current of other parameters is necessary to ensure the efficient use of electrical energy supplied through the power supply system to the electric rolling stock (ERS) when it is converted into mechanical energy of the train.
New opportunities for converting electric current, provided by modern power electronics, have opened a promising direction in the traction electric drive based on the use of more reliable and economical three-phase brushless electric motors -asynchronous and synchronous machines. To power three-phase current traction motors, three-phase current energy is required with smooth frequency and voltage level control for starting and smooth control of train speed [3-6].
Squirrel-cage induction motors are the preferred option for driving auxiliary ERS equipment due to their low cost, reliability and ease of maintenance. On most AC electric locomotives, auxiliary asynchronous motors receive three-phase power from a phase splitter, which is a short-circuited asynchronous machine that simultaneously performs the functions of a single-phase motor and a three-phase generator.
A modern adjustable electric drive is an electro-mechanical system that includes a power electric converter, an electric motor, a transmission mechanism and a control device, which, based on information received using sensors or observers from the constituent elements of the electric drive and the power supply, generates command signals that ensure the movement of the mechanical part
actuator with a given speed and acceleration and the operation of the entire device in the optimal (according to a certain criterion) mode. At the same time, many modern electric drives have such an arrangement; where the power converter, electric motor, gearbox and control device are a single module that is controlled via an information network similar to the Internet. Such an "intelligent module" has energy, technical and informational advantages compared to a "distributed" electric drive, where the electric motor, power converter and control system can be located tens of meters apart [3,5]. However, it should be noted that at present 75-80% of electric drives are unregulated, mainly due to the fact that there is no need for this technology, except for the cheek and protection conditions [9]. And only 20-25% of all electric drives, according to the conditions of technological processes, require precise control of speed and torque in steady state and transients. This group of electric drives is evolving towards the creation of an "intelligent power electromechanical module". At the same time, it should be noted that the cost of a power converter in an adjustable electric drive is 3-5 times higher than the cost of an electric motor [3,7]. The control device of the electric drive most often includes a motion controller that determines the position and speed of the actuator, and a control controller, or electrical controller, by which the voltage (flux linkage, torque) or current of the electric motor is regulated in accordance with the output of the motion controller. There are already developments where both of these controllers are combined. It turns out that the control device of an adjustable electric drive with high requirements for static and dynamic performance significantly affects the total cost of the electric drive. Therefore, despite the tendency to reduce the cost of elements of power electronics and microprocessor technology, the feasibility study of controlled electric drives should take into account the economic need to minimize costs while observing the technological requirements imposed by the technological process. In this regard, the issues of using a controlled electric drive should be solved on the basis of an analysis of its structures from the simplest to more complex, with a comparison of energy and cost indicators, functional and informational capabilities of the electric drive.
One of the important, multifaceted and complex elements of the energy systems of electrified railway transport is the electric drive (ED) on board the electric rolling stock (ERS). As you know, the concept of ED includes the following components: an energy source, an electrical converter, a motor device, a transmission device, a working machine or an actuator, a control and information device. Each of the listed components of the ED can be represented by a considerable variety of options.
The stationary electric power industry of railway transport provides for the widespread use (as in other industries) of electric drives for ventilation and pumping installations, where in recent decades the position of a frequency-controlled electric drive (FCED) based on AVI with AD has been significantly strengthened. A steady increase in the share of FCED also occurs in the traction and auxiliary ED of locomotives.
Features of the AD power supply in the auxiliary ED on the ERS are the asymmetry of the phase supply (when powered by an electromechanical phase
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frequency
The most promising technical solution in the field of auxiliary ED ERS can be considered today as the organization of power supply for three-phase AD from a three-phase AVI. In this case, it is possible to obtain a symmetrical three-phase supply voltage stabilized in magnitude on the AD stator, the frequency of which is adjustable, providing a variable performance of motor-fans, as well as the formation of starting and braking modes of motor-compressors. Thanks to the noted properties, it is possible to achieve a high use of the installed power of the AD, there is no need to overestimate it in case of a decrease in the supply voltage, the current operating modes are optimized by eliminating current surges during start-up and switching. The specificity of the mechanisms in the auxiliary ED is as follows (regulation of the rotor position is not required, the range of speed regulation is relatively small (with V/f-regulation without speed feedback, the speed regulation range is about 20, when using feedback it can be increased to 200 ), precision speed control is not required, high speed is not required, it is possible to power several AD from one AVI), which is currently the most widely used AVI with scalar control. The main element base of fully controlled semiconductor switches for AVI auxiliary ED are insulated gate bipolar transistors (IGBTs and high-voltage HV IGBTs ).
The disadvantage when powered from the AVI is the additional losses in the AD from the higher time harmonics of the current, as well as losses in the AVI circuit. Static converters of modern FCED, including those used to power three-phase AD in the auxiliary ED of the ERS, have a high efficiency (about 95% in nominal mode) [7-10], and also make it possible to obtain the efficiency of the supplied AD close to the nominal one.
Possible schemes of power circuits of static converters for use in auxiliary ED are diverse [3] (see Figure 1.). In the diagrams in Figure 1, galvanic separation of highvoltage power supply circuits (contact network) and low-voltage consumers with a voltage of 380 V and 220 V is provided [3-5]. In modern practice, a two-level three-phase AVI with hard switching of keys, made according to a bridge circuit, has become widespread .
Figure 1. - Scheme of the auxiliary converter of an electric locomotive with a two-level AVI and a
three-phase transformer
For example, in the structure of the power part of the auxiliary electric power supply, there are: power source - winding of the auxiliary needs of the traction transformer; uncontrolled rectifier; impulse DC voltage converter (ICDV) step-up type; a DC link at the input of the AVI, containing smoothing and resonant (tuned to a harmonic with a frequency of 100 Hz) electric LC filters; three-phase AVI according to the bridge circuit; AD power cables. Conclusion
Actual tasks in the development of new and analysis of processes in existing systems of auxiliary ED based on FCED with AVI and AD are, including in terms of energy efficiency:
-ensuring electromagnetic compatibility of the frequency-controlled asynchronous
ED;
- selection of optimal AD start-up modes;
- issues of reactive power compensation.
Completion of these tasks can be achieved by improving the quality of development and operation of an auxiliary electric drive of electric locomotives by creating calculation methods, studying with their help the performance and quality of operation of auxiliary electric drive circuits in various modes.
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