Traction Motor Research Articles

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.

Mathematical modeling of torsional vibrations of the wheel-motor unit of mains diesel locomotive UZTE16M

The article considers methods for studying torsional vibrations of the wheel-motor block of a diesel locomotive UZTE16M. The diesel locomotives in question were modernized at the structural enterprise “O’ztemiryo’lmashta’mir” (Machine building and repair in Uzbekistan Railways company) under the joint-stock company “O’zbekiston temir yo’llari” (Uzbekistan railways). The authors of the article developed a dynamic model for the analysis of torsional vibrational movements that occur in the traction transmissions of the UZTE16M diesel locomotive, taking into account the geometric dimensions of the electric traction motors of the main locomotives and the degree of their wear. Based on the model of the wheel-motor block of mainline locomotives, differential equations of the torsional-vibrational motion of traction gears are obtained in the form of Lagrange equations of the 2nd kind. The results of numerical studies of the amplitudes of torsional vibrations of the wheel-motor block of the UzTE16M locomotive at different frequencies are presented. All calculations were performed in the MATHCAD 15 environment.

Моделирование процесса определения технического состояния тяговых электродвигателей электровозов 2ЭС6

Or positive results in reducing the number of failures of electric traction engines, predictive diagnostics in operation is proposed. The development of malfunctions in electric traction engines directly affects the registration of analog signal values by on-board equipment. Some distinctive criteria have been identified by which the technical condition of electric traction engines can be assessed. The previously developed algorithm for searching for electrical damage has been improved. The presence of a difference in armature current between adjacent bogies and pairs of the same type of electric traction engines is pointed out, the dependence between a serviceable and faulty electric traction engine in the form of discrepancy in correlation coefficients is revealed. All the revealed conditions are added to the algorithm for determining the technical condition, the processes of which are built on the KNIME intelligent analysis platform. The process of determining the technical condition with the output of the result on the serviceability / malfunction of the electric traction engine is modeled. A pair of electric traction motors with a potential malfunction is also identified. The relative modeling error, which is at an average level, allows us to partially solve the problem of occurrence of failures of electric traction engines during operation. The application of the model along with the existing methods improves the quality of predictive diagnostics of modern locomotive equipment.

Optimization-Based Design Model for Electric Traction Motors Considering the Supply Risk of Critical Materials

Electric Vehicles (EVs) are considered among one of the ‘clean’ energy technologies in the transportation sector because the vehicles themselves do not generate combustion emissions. However, the substantial environmental footprint associated with the materials needed to create these technologies (extraction, manufacturing, and solid waste at end of life) calls into question their ‘clean’ label. In addition, their increasing demand adds to the existing supply risk (SR) through the requirement of critical materials. To address this, the purpose of this study is to establish a design model for electric traction motors, which are used in EVs, that will address the SR issues early in the design stage. The design model incorporates a genetic algorithm with the following objectives: minimum motor mass, minimum energy consumption, and minimum SR-equivalent. The SR-equivalent objective prioritizes the minimization of materials with high SR. Using the case study of a surface-mounted permanent magnet synchronous motor, results show how each objective is related to each other and to the parameters chosen as variables. Further analysis shows the benefits of minimizing for SR-equivalent of required materials. Future work is needed to improve the design model in terms of other important metrics such as minimizing environmental impact and cost.

Повышение эффективности грузоперевозок на основе совершенствования механической части электровоза 2ЭС6

The key problems of railways are presented, the cause-and-effect relationships between the dynamic characteristics of a typical scheme of a locomotive axle box suspension, the features of the traction engine suspension and malfunctions of its mechanical components are revealed. The impact of the properties of the spring suspension of the electric locomotive on emergence of defects in rails and wheels is reflected. A brief overview of foundations of the theory of invariance and application of the compensation method of external disturbances to improve the indicators of locomotive dynamic qualities is presented. Mathematical modeling of oscillations of the «locomotive-track» system with standard and upgraded systems of the axle box stage of the spring suspension of the 2ES6 electric locomotive has been performed, which makes it possible to evaluate the effectiveness of the proposed method for improving the dynamic qualities of the locomotive based on application of compensation of external disturbances compared with the standard scheme of the box stage of the 2ES6 electric locomotive. In order to reduce dynamic loads in the body of the traction motor and in the supports of motor axial bearings arising from horizontal oscillations of the electric locomotive, a new technical solution has been proposed which increases the reliability of motor axial bearings, their attachment points and the body of the traction motor.

Improving the temperature resistance of traction electric motors using a microprocessor control system for modern locomotives

Temperature control of traction electric motors running on direct current with the help of a modern microprocessor-based locomotive control system is analyzed in the paper. Development of a methodology for calculating the temperature of the windings of traction electric motors operating on direct current, based on a modern control system has been discussed. To determine the dependence of the temperature of traction motors on the motion profile and weight of the rolling stock.

Adaptive Fault Diagnosis and Decision-Making Method Based on Multi-Spectrum Evaluation and Fusion for Traction Motor Bearings

Traction motor bearings are critical research objects of motor fault diagnosis due to their high failure rate. Nowadays, numerous frequency-domain analysis methods have been proposed for rolling bearing fault diagnosis. However, most methods have rigorous requirements on the applicable conditions and may fail to diagnose when working conditions change, which significantly limits the broad application of the method in practical engineering. Therefore, this article presents an adaptive fault diagnosis and decision-making method (AFDDM) based on multi-spectrum evaluation and fusion. The method can give appropriate weights to each spectrum in different conditions to ensure the stability of fused spectrum and convert the spectrums into more intuitive fault probability to give maintenance advice. Also, the AFDDM method achieves the purpose of evaluating the spectrum by extracting the eigenvalue vector and utilizing the local tangent space alignment (LTSA) to reduce dimension. Then, a decision-making model based on multi-spectrum is proposed to divert the spectrums into fault probability. By this method, the evaluation fusion of spectrums with different effects and decision-making is realized. Real bearing fault signals from different data sets are selected to verify the effectiveness of the proposed method and show that the proposed method has better engineering applicability and robustness.

Electromechanical transmission of an all-wheel drive vehicle with a central traction electric motor

Modern approaches to the construction of a kinematic scheme of an electromechanical transmission are considered. It is shown that for all-wheel drive transport and transport-technological mobile platforms, it is advisable to use a central traction electric motor operating with a two-mode reduction gear connected in series and a transmission based on controlled inter-axle and inter-wheel power distribution mechanisms. It is shown that such a scheme makes it possible to improve the operating conditions of the traction motor, reduce its installed power, dimensions and weight. At the same time, it remains possible to fully control the traction force on the drive wheels, use power recovery, and work in the mode of dynamic stabilization of the motion trajectory. The structure of the electromechanical transmission based on the described principles is proposed. The principles of operation of controlled interaxle and interwheel power distribution mechanisms based on gear differentials are considered. Examples of simplified kinematic schemes of promising mechanisms are given and principles of their control are proposed. The principles of determination of external parameters and synthesis of kinematic schemes of interaxle and interwheel differentials with friction control are considered.

Computational methods for studying the thermal state of frequency-controlled asynchronous traction motors

The article discusses methods for calculating the thermal state of a frequency-controlled asynchronous traction motor, and provides calculations of the thermal state of an asynchronous motor powered by a semiconductor frequency converter with an autonomous inverter. Methods for assessing the thermal state of traction asynchronous electric motors of locomotives under various operating modes are considered. Computational methods for assessing the thermal state of asynchronous motor units allow you to continuously monitor the thermal state of an asynchronous traction motor and prevent possible emergencies in a timely manner.

A fundamental investigation of the interaction and impact of controlled torque ripples on gear mesh dynamics

Gear trains are plagued by self-excited vibrations that are concentrated at the mesh frequency and its harmonics due to their varying mesh stiffness and deviations from the ideal involute profile. This is even more pronounced in spur gears due to their lower contact ratio in comparison to helical gears. For an electric vehicle, due to the absence of an internal combustion engine, noise and vibration signature of the gearbox becomes an important aspect of the vehicle's comfort. However, the presence of a traction motor offers the advantage of having a potential actuator for actively countering these vibrations without adding any additional weight or packaging constraints. This paper presents a fundamental insight into the effect of introducing controlled torque ripples at the mesh frequency and its harmonics, on the noise and vibration characteristics, and the efficiency of the gear mesh. The study utilises a dynamic model of a single stage gear train that accounts for the time varying mesh stiffness and sliding friction at the gear teeth contact. This model is used to provide an understanding of gear mesh dynamics and their resulting interaction with the imposed torque ripples. The study demonstrates the positive effects that controlled torque ripples can have on the noise and vibration behaviour of gear trains and the underlying mechanics that govern this improvement.

Model Predictive Control of Battery-Powered Trains for Catenary-Free Operation

Rail transportation is recently making a comeback with stunning results from technological viewpoint. While the efficiency of trains is well known, many aspects related to energy management still need to be tackled, including sustainability and optimization issues. These issues are central to the control community, and in this context model predictive control (MPC) is a powerful control approach for its capability of guaranteeing constraints satisfaction, while minimizing a predefined cost function. In this article, we exploit these advantages to provide more efficient control of the electric equipment inside railway vehicles. More precisely, the proposed MPC approach is capable of addressing the challenging scenario of partially catenary-free tracks for trains. These are equipped with batteries, which have to supply traction motors and parallel-connected auxiliary loads in an efficient manner, while reducing the amount of losses over the electric lines. Simulation results, based on real data provided by the industrial partner Alstom rail transport, show the effectiveness of the proposal.

Vertical Coupling Dynamics Analysis of Train-track System with Considering Traction Motor Vibration

Vertical Coupling Dynamics Analysis of Train-track System with Considering Traction Motor Vibration

Sampling of a driving cycle for e-trucks with a mechatronic transmission

Traction battery vehicles (TBV) are currently gaining more and more popularity and are gradually replacing vehicles with ICE and traditional transmissions. The usage of an electric traction drive as part of TBV solves a number of problems that manufacturers of this type of equipment face today: reducing harmful emissions into the atmosphere, reducing noise, used lubricants recycling, and the increase of the energy efficiency. From the point of view of the scientific research, this type of wheeled vehicles is also of high interest due to the large number of problems and tasks that have formed at the moment. It is a common knowledge, that one of the main problematic issues for the TBV is a rather limited range. In cargo electric vehicles and buses, in order to reduce the size and increase the usable volume of the passenger compartment or cargo space, as well as to unify the products of the power unit and drive, there are used the transmissions, which are the combination of mechanical and electrical components with appropriate control systems. The mechanical component includes a gearbox with one or more gear ratios, an inter-wheel differential, axle shafts, bearings and other components. The electrical component is a traction motor located directly in the drive axle (integrated) or on the outside of the crankcase, as well as a voltage converter with a control system and the necessary switching elements. Similar implementations of the driving axles of vehicles with traction batteries are called mechatronic transmissions.

Fatigue aging of insulation of traction motors of diesel locomotives

This paper analyzes the problem of occurrence and development of fatigue processes in the insulation of traction motors of autonomous locomotives. Factors causing destruction (cracking, delamination, occurrence of voids) of insulation in operation have been studied in the course of the research. Three characteristic stress cycles (reversible, repetitive, random) were described to make fatigue failure predictions. Outcomes of investigations of temperature conditions of windings of electric machines of diesel locomotives show that during operation the insulation experiences variable thermomechanical stresses. Received data can be recommended to take into account during the creation of new electric machines for diesel locomotives, as well as during the operation and resource recovery of already existing ones.

Electric Vehicle’ Powertrain Thermal Analysis

The purpose of this paper is to discuss the thermal analysis of electric vehicle powertrains. Due to their high-power output requirements, electric vehicles' traction motors generate significant amounts of heat. Motor winding insulation deteriorates rapidly when overheated. Overheating causes permanent magnets in the rotor of interior permanent magnet motors (IPMs) to lose their magnetic properties, resulting in inefficient operation. Both ends of the stator and rotor must be cooled to maintain a constant temperature. For a motor cooling system to function effectively, it must be able to handle a wide range of temperature, humidity, and dust levels. In this paper, we present an automated meshing of windings, slots, gaps, and flow paths that allows us to accurately thermal analyse liquid-cooling temperature fields.

Development of a design system for synthesis and analysis the motor wheel based on a valve electric motor of combined excitation for hybrid and electric vehicles

The article describes a project to create an electric transmission for ground vehicles. As a layout, a motor-wheel variant is proposed, in which a traction electric motor, power electronics, control system and brake system are integrated into the wheel disk. This arrangement of the traction motor allows you to free up the space of the car for comfort and placement of the electric power storage. A combined excitation machine is proposed as an electric motor, the magnetic flux in which is created simultaneously by permanent magnets and an excitation winding. Permanent magnets allow you to increase the power in the limited dimensions of the disk, and the excitation winding allows you to adjust the magnetic flux, which significantly expands the range of speeds and torques of the vehicle. The design of the electric motor is innovative and protected by a patent of the Russian Federation. To develop a number of similar motor wheels, a design system has been proposed, which consists of two parts: synthesis and analysis. The synthesis system generates the optimal geometry of the electric motor for a specific technical task of the customer. It contains a multi-level structure that allows you to implement developments for various project situations with and without restrictions. The system contains seven such levels. Optimality criteria can be selected depending on the requirements of the project. The analysis system is based on the principle of a digital double. Its methodological basis is the finite element method. The system allows you to conduct a detailed analysis of the electromagnetic and thermal state, to obtain all the necessary integral characteristics. The performance of the design system has been tested on a digital analogue of a real racetrack, which is divided into sections with specified speed modes. The program outputs 15 parameters of both the car and the electric motor. In conclusion, the article shows the design study of a motor wheel for a racing electric car. The design of the prototype and the results of its tests are presented. The design system for the development of motor wheels based on a valve motor of combined excitation can be used for mass production.

Device for measuring the magnetic scattering field of the frontal part of the stator winding of a traction asynchronous electric motor of an electric rolling stock

The article deals with the issues of improving the energy efficiency of mainline locomotives with asynchronous traction motors by determining the characteristics of the traction drive using a device for measuring the magnetic scattering field of the frontal part of the stator winding.

Unified Maximum Voltage Utilization Controls for Half-Centralized Open-End Winding Permanent-Magnet Motor Systems

In order to extend the speed range and reduce power electronics devices of the primary permanent-magnet linear motor traction system, a half-centralized open-end winding topology is studied in this article, in which <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> movers are supplied by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> +1 voltage-source inverters. In order to maximize the speed range, two unified maximum voltage utilization control (UMVUC) methods are proposed for the studied traction system, which can be easily implemented for any number of movers. The first UMVUC is named as the original UMVUC, and it requires a heavy computation burden, which makes the implementation difficult when the number of movers is large. For the linear motor system, the relative positions of all movers are approximately constant. Based on this feature, the second UMVUC named as simplified UMVUC is proposed, which can significantly reduce the computation burden. In order to suppress the zero-sequence current (ZSC) and reduce the switching loss, a zero-sequence polarity assignment method is employed in the proposed UMVUCs. An experiment platform is developed, and the effectiveness of the proposed UMVUCs has been validated by experimental results.

Optimization-Based Estimation and Model Predictive Control for High Performance, Low Cost Software-Defined Power Electronics

A combined optimization-based estimation (OBE)-model predictive control (MPC) technique is developed to improve the dynamic performance of a reconfigurable LC-based power module with lower cost and less noise/oscillation. The developed OBE-MPC technique and the corresponding power module are based on a software-defined power electronics concept that can be reconstructed as different topologies and applied to various load/source applications, e.g., dc/dc converters, dc/ac single/three-phase grid-connected inverters, and ac/ac motor traction inverter to improve the energy conversion performance. The software-defined power electronics are designed in a generalized way by manipulating a different number of OBE-MPC power modules with holistic high-level control functions for wide applications. Symmetrically mirrored to the MPC, the OBE is configured as a constrained finite time optimal estimation (CFTOE) problem to solve the quadratic cost function based on the past sampling information. With the designed OBE, the sensor count is reduced with less noise/oscillation. And the highly accurate OBE contributes to the correction of possible modeling parametric or sampling errors. The integration of OBE-MPC algorithms improves both the steady-state and dynamic performances with less noise/oscillation, more robust transient behavior, and higher control bandwidth. The explicit design of OBE-MPC algorithms makes it possible to implement the functions on a low-cost DSP. Also, the state-space modeling of OBE-MPC for the LC-based power module is immune to the output side unknown inductance, which further improves the parametric accuracy. The proposed methods have been validated experimentally.

Sliding mode control rotor flux MRAS based speed sensorless induction motor traction drive control for electric vehicles

&lt;abstract&gt;&lt;p&gt;Climate change has highlighted a need to transition to more sustainable forms of transportation. Electric vehicles (EVs) and hybrid electric vehicles (HEVs) offer a promising alternative to conventional gasoline powered vehicles. However, advancements in power electronics and advanced control systems have made the implementation of high performance traction drives for EVs and HEVs easy. In this paper, a novel sliding mode control model reference adaptive system (SMC-MRAS) speed estimator in traction drive control application is presented. However, due to the unpredictable operational uncertainties of the machine parameters and unmodelled non-linear dynamics, the proportional-integral (PI)-MRAS may not produce a satisfactory performance. The Proposed estimator eliminates the PI controller employed in the conventional MRAS. This method utilizes two loops and generates two different error signals from the rotor flux and motor torques. The stability and dynamics of the SMC law are obtained through the Lyapunov theory. The potential of the proposed SMC-MRAS methodology is simulated and experimentally validated for an electric vehicle application. Matlab-Simulink environment is developed and proposed scheme is employed on indirect vector control method. However, for the experimental validation, the dSPACE 4011 R &amp;amp; D controller board was utilized. Furthermore, the SMC-MRAS performance is differentiated with PI-MRAS for speed regulation performance, tracking and estimation error, as well as the fast minimization of the error signal. The results of the proposed scheme illustrate the enhanced speed estimation, load disturbance rejection ability and fast error dynamics.&lt;/p&gt;&lt;/abstract&gt;