Traction Asynchronous Motor Research Articles

The analysis of principles of continuously variable transmission of tractors

BACKGROUND:Modern agricultural activity requires the use of hightech equipment such as, in particular, a multifunctional tractor, which, according to actual trends, should be an autonomously controlled mobile power plant. In modern tractors, meeting current requirements, multiflow shaft-planetary gearboxes with cumulative effect are used.
 AIMS:Comparison of the operation principles of two types of automatic tractor transmissions: with hydrostatic drive and with electromechanical drive.
 METHODS:During the research, a literature review of printed and online publications with technical description of the transmissions of the considered design was carried out.
 RESULTS:The operation principles of two types of automatic tractor transmissions were considered: with hydrostatic drive (Fendt VarioDrive) and with electromechanical drive (Ruselprom-electroprivod LLC).
 The operation principle of the Fendt VarioDrive transmission (planetary multiflow transmission with mechanical and hydrostatic branches) consists in dividing the torque coming from the internal combustion engine by a planetary gearbox into mechanical and hydrostatic branches, followed by summation of flows by a collecting shaft. The change in the gear ratio and movement direction of the tractor is controlled by the ECU by means of controlling the hydrostatic branch of the transmission. The transmission is nominally continuously variable due to the absence of gears as such.
 The set of traction electrical equipment of the transmission developed by Ruselprom- electroprivod LLC, installed on a tractor, includes:
 an synchronous motor generator with a power converter and a microprocessor control system;
 a traction asynchronous motor of the central drive with a power converter and a microprocessor control system;
 a DC-DC converter for energy supply of auxiliary equipment.
 power converters and a DC-DC converter are integrated into the power electronics unit;
 a top-level controller with controls and indicator panel in the drivers cab.
 The control system of the electromechanical transmission provides with full control of its operation and the functioning of the internal combustion engine. The operation principle of the system is based on the essentials of hybrid transport operation. Tractor movement is possible in one of two ranges: range 1, operational (0...18 km/h) and range 2, transport (0...42 km/h)
 CONCLUSIONS:Due to the modern concept of electric drive units, layout solutions with an electromechanical drive having an electric generator in their design are more promising and applicable in the future, especially for trailed equipment.

Analysis of the traction motor electrical parameters of the trolleybus

The technical equipment of modern trolleybuses (increased power of traction motors, regenerative-rheostatic braking, anti-slip and anti-lock systems, an on-board computer for monitoring and controlling the operation of the traction drive, GLONASS satellite systems, Internet access) increases the requirements for the quality of electrical energy and the electromagnetic compatibility of the installed equipment. In the course of the study, the electrical performance of the trolleybus traction asynchronous motor (voltage, current, voltage sinusoidal shape, total coefficient of harmonic voltage components) has been analyzed. Due to difficulties in the supply of foreign electrical equipment, primarily power electronics elements used to control the operation of the traction motor, there is an increasing need to improve measures for the maintenance of trolleybuses to increase the reliability and uptime of the equipment. The advantages of using the methods of quantitative thermography, analysis of the quality of electrical energy and control of the hardness of cable insulation have been experimentally established. With the help of an analyzer of electric energy quality, measurements of the quantitative indicators of the operation of the electric motor have been carried out; the thermal imager has been used to assess the thermal state of contact connections and cable routes. The use of new diagnostic methods is of particular relevance in the course of continuous long-term operation of electric transport in the Far North.

Aspects Regarding the Optimization of Cross Geometry in Traction Asynchronous Motors Using the Theory of Nonlinear Circuits

Modern electrical traction uses asynchronous motors for driving railway vehicles because these motors have a lot of advantages in comparison with the classical, direct current motors. Reducing active and reactive electrical energy consumption is a concern in the case of these motors, meaning a decrease in exploitation costs. The research carried out shows, by results and simulations, the effects of the geometry optimization for the stator and rotor lamination and emphasizes how much the total and exploitation costs. Cross geometry optimization means preserving constant electromagnetic stresses, using the same gauge dimensions, preserving the constant ampere-turn for a pole pair, having a maximum torque exceeding the imposed limit, and increasing the air-gap magnetic induction. The results obtained indicatea decrease in the total cost, by 42,600 € (12.31%), for a asynchronous tractionmotor in comparison with the existing variant.

Modeling vector control of the asynchronous drive of electric rolling stock auxiliary machines

Introduction. The development of power semiconductor devices and technology served the basis for fundamentally new types of frequency-controlled electric drives with traction asynchronous motors on the rolling stock of electrified railways. Therefore, problems of theoretical and experimental study of the operating modes of the mentioned drives become actual. This article is a theme continuation of the asynchronous machines control on the AC locomotive, which was presented in no. 5 of Russian Railway Scientific Journal in 2021.Materials and methods. For analysing the frequency converter operation, the authors used mathematical modeling methods, which allowed evaluating the motor operation in various modes without resorting to time-consuming full-scale tests. Recently, software packages for visual programming have been developed, aimed mainly at domestic users, which are not inferior in their capabilities to leading foreign counterparts. Among such software products is SimInTech software for modeling technical systems, developed by 3V Service. The software focuses on solving various applied problems, particularly, on modeling a vector control system for an asynchronous drive.Results. The authors developed a mathematical model of an asynchronous drive of auxiliary machines of an electric locomotive in a rotating coordinate system d – q by the SimInTech application package and concerning the cross-impact influence of d and q control channels.Discussion and conclusion. The developed complex of an asynchronous motor and a vector control system enable to work out various algorithms for improving the energy efficiency of the operation of asynchronous auxiliary machines of an electric locomotive by applying the proposed algorithm for choosing the optimal value of the rotor flux linkage. The presented vector control structure also enables to implement it on the basis of modern microcontrollers, helping to reduce programming time.

ESTIMATION OF ENERGY INDICATORS OF A MULTI MOTOR TRACTOR ELECTRIC DRIVE FOR PUBLIC TRANSPORT

The purpose of the work is to analyze the energy parameters of a multi-motor asynchronous traction electric drive in a city vehicle to ensure a reduction in electric energy losses when driving along the route. The research was carried out for a lightweight double-decker bus, the maximum number of passengers transported is set at 100 people. To achieve the goal, mathematical modeling was used in the MatLab package, in which energy losses were calculated in the multi-engine electric drive of a bus with a different number of traction asynchronous motors. The calculation was carried out for the most characteristic sections of the city cycle of the bus: constant modes of movement with different speeds and transient modes of acceleration. To control the speed of the engines, a proportional law was used to change the voltage on the stator winding and frequency, which correspond to the voltage frequency values at the stator winding of 25 Hz and 50 Hz and, respectively, the standard phase ratio of 110 V and 220 V. The change in the loading moment of the vehicle engines due to the change in the rolling friction force of the wheels for three cases of a complete, half-complete and empty bus is taken into account. The load change due to air resistance when the speed changes is taken into account. In operation it is shown that application of multi-motor asynchronous electric drive allows to reduce energy losses in traction asynchronous electric motors when vehicle is moving at constant speed and at acceleration at different number of carried passengers. Moreover, in order to achieve energy saving, the number of engines used in a multi-motor electric drive must vary depending on speed and acceleration, as well as on the total load moment of the multi-motor electric drive.

The transfer function of a traction asynchronous motor controlled by a four-square converter

An expression for the transfer function of a traction asynchronous motor with a four-square converter is derived. It is shown that the basic properties of the traction motor, which are a four-square converter, correspond to the linearization coefficients. The values of linearization coefficients for a typical system in the entire region of equilibrium states are given.

Systems mutual loadings of traction asynchronous cars

The review of methods of post-repair tests of traction asynchronous motors under conditions of locomotive depot is carried out.The necessity of introducing special stands for post-repair tests is shown in order to improve their quality, reduce the number of failures of service equipment, improve safety of the railway transport. Let’s consider a question of power supply of the research asynchronous engine in wide frequency range and also a possibility of creation of the universal stand for testing important asynchronous engines of the electrorolling stock. Survey of possible versions of the scheme mutual loadings of asynchronous electrical machines which can be used for testing traction asynchronous engines of the rolling stock is executed. Such systems can be constructed both with use of the static converter of frequency, and without it. The given short characteristic of each alternative, certain advantages and shortcomings of each of system options. It is shown that systems with use of static converters of frequency differ in high power efficiency, allow to carry out tests in the wide frequency range of power supply, however have higher prime cost. Schemes without converters of frequency differ in smaller power efficiency, impossibility to carry out tests in the wide range of frequency of power supply, high level of consumption of reactive power . The results of the carried-out analysis can be used when choosing rational option of a system mutual loadings of asynchronous electric motors which will differ in higher functionality and power efficiency. Use of such systems will allow to lower capital expenditure for creation new and modernization of traction electrical machines that exist at the station for test.

Development of the ñonverter structure that enables power supply to traction induction motors of mine electric locomotives from different levels of voltage

We have proposed an adjustable structure of the converter of energy of electric drive in the electrotechnical complex of a mine electric locomotive from power sources with different voltage levels ‒ from a contact network and a battery of traction accumulators. A characteristic feature of the converter is the presence of inverter units that can be connected either sequentially or in parallel. When powered by a low­voltage source, inverter units are connected in parallel over the entire range of change in the output voltage. When powered by a high voltage source, inverter units are connected sequentially in the range of low output voltages and in parallel in the range of high output voltages. Such an approach makes it possible to align the power voltage levels of traction asynchronous motors of a mine electric locomotive at a lower level. The expected alignment of voltage levels is carried out at a lower level compared to a standard circuit of the three­phase bridge autonomous inverter and is achieved by controlling the paired bridges in the power circuit of traction induction motors. Given this, the frequency of voltages of width­pulse modulation does not change, which is important for the process of reducing dynamic losses of power in the drive’s elements. It has been confirmed that an increase in the output voltage distortion coefficient in the IGB­transistors of the inverter with the minimal level of energy losses in the electric drive’s elements is achieved by modulating the voltage at a constant switching frequency at different voltage levels. We have proven the fact that the best indicators for the harmonic coefficient were obtained at frequencies about 30 Hz, which are the working ones, so the converter operating mode is most effective at these frequencies. The result of analysis of the classical scheme of the inverter has revealed that increasing the frequency of pulse­width modulation by three times significantly increases electrical losses in the windings of traction electric motor. In the proposed circuit of the voltage inverter of engine’s power, at leveling the voltage at low level, there is no need to increase the frequency of pulse­width modulation, which does not lead to a growth in the electrical losses in a traction motor

Simulation of Traction Electric Drive with Vector Systems of Direct Torque Control

The article deals with investigation of electromechanical and energetic characteristics of traction electric drive with vector systems of direct torque control. As a controlled object the traction asynchronous motor ДТА-1У1, which is used to drive the trolley-bus is considered. At the present time the usage of traction asynchronous electric drives for town transport is relevant. Due to development of power electronic devices and microprocessor-based control systems it became possible to replace DC electric drives with electric drives with asynchronous motors. The article contains brief description of two different types of control systems: field-oriented control (FOC) and direct torque control (DTC). Principles of work for both systems are considered and the main advantages and disadvantages associated with the use of these systems are pointed out. The models of both systems for traction asynchronous electric drive, built in modeling environment MATLAB/Simulink, are given in this article for further comparative analysis. As the main quality factor of control total harmonic distortion (THD) is used.

Several peculiarities of designing traction asynchronous motors. Part 2

Examples of designing asynchronous traction motors with an optimized geometry of active parts are shown. The influence of dimensions and parameters of active parts on motor performance is studied. Problems of matching the parameters of traction motor and power converters and control synthesis are discussed. Examples of vehicles equipped with electrotechnical equipment developed at Ruselprom are shown.

Traction and energetic characteristics of a trolley bus drive and the algorithm of a controlling traction asynchronous motor

The results of bench and operational tests of AT250L4Y2 traction electric motors in a system of the traction drive of a trolley bus are described. An example is given of implementing testing equipment enabling one to simulate the operation of the traction motor and the drive at the conditional settlement stage.

The temperature effect on the performance of a traction asynchronous motor

The faults and damages of the asynchronous motors currently used in the traction rolling stock are reviewed. It is shown that a significant number of failures in operation are due to the excessive temperature in the stator coil and how it affects the mechanical characteristics and the traction performance of the asynchronous motor windings.