Traction Motor Design Research Articles

Design and Optimization of Electric Vehicle Traction Motor Considering Rotor Topology and Manufacturing Uncertainty

Design and Optimization of Electric Vehicle Traction Motor Considering Rotor Topology and Manufacturing Uncertainty

Traction motors for electric vehicles: Maximization of mechanical efficiency – A review

With the accelerating electrification revolution, new challenges and opportunities are yet emerging, despite range anxiety is still one of the biggest obstacles. Battery has been in the spotlight for resolving this problem, but other critical vehicle components such as traction motors are the key to efficient propulsion. Traction motor design involves a multidisciplinary approach, with still significant room for improvement in terms of efficiency. Therefore, this paper provides a comprehensive review of scientific literature looking at various aspects of traction motors to maximize mechanical efficiency for the application to high-performance Battery Electric Vehicles. At first, and overview on the mechanical design of electric motors is presented, focusing on topology selection, efficiency, transmission systems, and vehicle layouts; Special attention is then paid to the thermal management, as it is one of the main aspects that affects the global efficiency of such machines; thirdly, the paper presents a discussion on possible future trends to tackle ongoing challenges and to further enhance the performance of traction motors.

Parametric design, life cycle assessment, and optimization of a discrete product with application to an electric traction motor

Humans are surrounded and even dependent on discrete products for their daily activities. Product design processes have been vastly studied towards a healthy economic prosperity and other technical objectives (e.g., low risk). However, recent studies show that these methods have been lacking in terms of the environmental challenges humanity faces in the present and future. This study proposes a novel design framework that incorporates a parametric life cycle assessment (PLCA) as part of the optimization-based design model of a discrete product at early stage. Electric traction motor design applied to an electric vehicle is used as a case study. The results of performing a multi-objective design problem and an uncertainty analysis using Monte Carlo simulation show the usefulness of incorporating the PLCA in a transparent manner, as required by the International Standards Organization. Future work suggests investigating the expansion of this technique to support a broader range of objective functions.

Implementation of a Metamodel-Based Optimization for the Design of a High Power Density Wound Field Traction Motor

Implementation of a Metamodel-Based Optimization for the Design of a High Power Density Wound Field Traction Motor

Energy Efficiency Improvement Concept for Autonomous Locomotives

The growing attention to the issues of increasing energy efficiency of railway transport results in suggesting various designs of traction rolling stock with the most advanced technical solutions, but, unfortunately, many of them remain only at the development or prototype stage.The analysis of operating experience of existing mainline locomotives is proposed to help to develop fundamental principles of the concept of improving the energy efficiency of autonomous locomotives, aimed at creating a modular locomotive structure that makes it possible to coordinate operational loads with the operating modes of traction equipment to provide the best conditions for converting and transferring energy to wheel sets. Modern on-board systems of locomotives record many parameters that can be used both to determine the energy efficiency of the locomotive, as well as to evaluate new technical solutions aimed at the use of discrete-adaptive control of the modular design of diesel generator sets and traction motors under the operating conditions of mainline locomotives.Implementation of the proposed concept could make it possible to save up to 20 % of diesel fuel during transportation work, which was confirmed during testing a prototype locomotive.

Kayış Tahrikli Asansör Çekiş Makinesinin Tasarımı ve Üretimi: Çift Taraflı Kayış Sisteminin Modellenmesi

Elevator traction motors are critical components of elevator systems. After the structural analysis of the traction motor, it is necessary to proceed to the production processes for the comfortable and safe use of elevator systems. In this study, the static load values for bearing lifetime calculation, belt selection, and finite element analyses (FEA) were determined. According to calculated loads; materials, bearings, belt, pulley, brake, and encoder were selected. In order to obtain a design in accordance with elevator standards, motor parts were examined for structural analysis. Finite element analyses were carried out according to the determined maximum static load values, and a new belt elevator traction motor design that provides the safety coefficients has emerged. When the FEA analysis results of bending moments are examined; the maximum Von Mises stress acting on the motor frame and shaft was obtained 17.1 MPa and 27.62 MPa respectively. The maximum Von Mises stress was obtained under the torsional moment as 71.4 MPa and the shaft is 6.1 times safe against a torsional moment. This value is the minimum safety factor of the designed system and safety factors of bending moments are higher than this value. The designed elevator machine has got 12.9 kW rated power, 1.6 m/s cabin speed, and 1175 kg carrying capacity. The advantage of the proposed design is to eliminate the casting process with modular structure via double side belt system. The prototype of the designed motor was produced and it was observed that the motor provided the desired constraints as a result of the loading experiments.

A Computationally Efficient High-Fidelity Multi-Physics Design Optimization of Traction Motors for Drive Cycle Loss Minimization

Continuous improvement in performance of interior permanent magnet (IPM) machines is critical for electric vehicle traction applications. However, due to the cross-coupling and saturation effects, a significant amount of time-consuming finite element analysis (FEA) simulations are required to accurately estimate machine performance. Moreover, iterative design optimization will take significantly longer. In this article, an improved rapid performance estimation technique utilizing surrogate models is developed and coupled with a design optimization algorithm. The proposed framework has significantly less computational cost than alternative surrogate-based approaches, and efficiently employs drive cycle loss minimization for a multi-physics, multi-objective traction motor design optimization. Simulation and experimental results suggest the proposed optimization framework yields optimal designs more efficiently than existing methods while maintaining accuracy.

Comparative analysis of energy indicators based on engineering model-oriented design of traction motors

Paper deals with a comparative analysis of energy and mass-size indicators of virtual prototypes of two traction electric motors, with a view to their application to electric transportation vehicles. For this purpose, specialized software is used, allowing electromagnetic, structural and thermal optimization according to certain criteria. In conclusion, the results of the comparative analysis are summarized.

МЕТОДИКА ПРОЕКТИРОВАНИЯ ТЯГОВОГО ЭЛЕКТРОДВИГАТЕЛЯ ДЛЯ ТРАНСПОРТА

The article is devoted to the design of an asynchronous traction motor intended for work as part of an electric drive of vehicles: electric vehicles, electric buses, trams, trolley buses. The object of the study is a medium-sized bus. The required traction characteristics of the electric motor are constructed, the nominal and limiting characteristics of the increased torque. The dynamic characteristics have been built for a bus with a mechanical transmission and a diesel engine, as well as for a bus with an electric motor. A method is proposed for designing an electric motor based on mathematical modelling of its operation in the software complexes ANSYS RMxprt and INFOLYTICA MAGNET. According to this technique, the main parameters of the electric motor are determined. The results of modelling are given, graphs of the criteria dependence on the electric motor parameters. Experimental studies of the electric motor have been carried out. The results of mathematical modelling are compared with experimental ones. It was found that the discrepancy between the results of experimental and theoretical studies is no more than 5 %.

A Design Technique of Traction Motor for Efficiency Improvement Based on Multiobjective Optimization

With the increasing demand of driving range of new energy vehicle (NEV), design optimization for energy efficiency of traction motors became more important. However, traction motor design is complex since multiple objectives should be satisfied, such as the required torque-speed operating range and package and thermal constraints. This dramatically increases the computation time of the design optimization process, while the additional energy efficiency objective of the whole driving cycle. This paper proposes an equivalent driving cycle points extraction method, based on energy consumption equivalence to facilitate the design optimization of traction motors. This paper presents necessary rules of multiobjective optimization methods, and then gives an optimization process and proves the effectiveness.

Experimental Validation and Parameter Study of a 2D Geometry-Based, Flexible Designed Thermal Motor Model for Different Cooled Traction Motor Drives

For identifying new improvement potentials for electric traction motors, accurate models are needed. In this paper, a geometry-based 2D lumped parameter thermal network model for different electric traction motor and cooling concepts is studied and validated. In the second section, the design and functionality of the thermal model is explained. In the third section, the best fit of the literature correlations for describing the different heat transfer mechanisms was identified and a parameter study of the heat transfer coefficients was carried out and discussed. In the last section, the model is validated with measurement results from six different electric traction motors and drives units. For validation measurement results of stationary operating points, peak operating points and drive cycles are used. Based on the validation results, a model error of less than 10% is achieved for the most motor components in the different cooling concepts and traction motor designs. Inaccuracies and deviations are discussed and suggestions for improvement are made.

Dynamic modelling of traction motor bearings in locomotive-track spatially coupled dynamics system

For railway locomotive, its motor bearing is one of the key components, which is likely to be damaged due to the intensified vibration conditions caused by the wheel-rail interaction and gear mesh. In this paper, a locomotive-track spatially coupled dynamics model considering the dynamic effect of the traction power transmission is established to investigate the dynamic responses of traction motor bearings. The detailed structure of the traction motor, complex internal interactions of the rolling bearing itself, time-varying gear mesh stiffness, and wheel-rail interaction are considered. The simulated results indicate that the gear mesh excitation and internal interactions of the motor bearings significantly affect the dynamic characteristics of the rotor. The motor bearing at the driving end surfers more dynamic loads, and the internal interactions between the components are more intensified than that of the bearing at the non-driving end. Moreover, the skidding phenomenon of the motor bearing at the driving end is alleviated by the greater radial load. Additionally, the wheel-rail interaction with track random irregularity will deteriorate the working conditions of the motor bearings. The modelling method and results can provide helpful theoretical guidance for the motor bearing design and structure optimization of the locomotive traction motor.

Design of Traction Motor for Mitigating Energy Consumption of Light Electric Vehicle Considering Material Properties and Drive Cycles

Light electric vehicles (LEVs) are usually used as neighborhood electric vehicles (NEVs) for the second vehicle or car-sharing service. For LEVs, it is important to reduce energy consumption to have greater mileage at the same battery capacity. One of the direct ways to decrease energy consumption is the efficiency improvement of the traction motor, which is the main propulsion system. Also, the weight reduction of the traction motor can be a solution to energy usage mitigation. This paper suggested the design process of a traction motor for LEV considering material properties to minimizing the energy consumption of the vehicle. During the design process, vehicle simulation was adopted to calculate energy consumption. In addition, traction motor and battery which are the key components of LEV were mathematically modeled and used in the simulation. Using them, energy consumption was estimated within the change of stack length of the traction motor for some drive cycles. Finally, from these simulations, optimum power density is determined which minimizes energy consumption.

Design of Unskewed Interior Permanent Magnet Traction Motor with Asymmetric Flux Barriers and Shifted Magnets for Electric Vehicles

Interior permanent magnet synchronous motors (IPMSMs) are commonly used in electric and hybrid electric vehicles. Nissan Leaf electric vehicle (EV) uses skewed-rotor IPMSM as a traction motor. This motor is considered as a benchmark in this work. Although, skewing improves the torque quality of the motor by reducing the torque ripple, it reduces the average torque and increases the motor manufacturing complexity and cost. This article proposes improvements to the benchmark motor torque quality without skewing. The proposed motor uses the same stator winding and rotor magnet topologies of the benchmark motor with the same geometric constraints and magnet volume. Modifications are applied to the placement of the magnets in the rotor and the shape of the flux barriers to achieve the performance requirements. The design procedure of the proposed unskewed design is illustrated. Moreover, the electromagnetic performance of the proposed design is investigated. The design shows competitive performance in terms of the average torque, torque ripple, cogging torque, and efficiency compared to the benchmark motor. The mechanical integrity of the design is also verified. The proposed design is found to be a suitable alternative to the benchmark traction motor with a reduced rotor weight and without skewing.

Analysis and Design of a High-Performance Traction Motor for Heavy-Duty Vehicles

Due to environmental issues and depletion of resources, global attentiveness in electric vehicles (EVs) is growing. In particular, research on high specification motors for driving large EVs has attracted a lot of attention. In this study, an analysis and design process for a motor that can be universally applied in heavy vehicles to reduce environmental pollution was introduced. Motors for driving heavy vehicles require high specifications. Thus, an interior permanent magnet synchronous motor (IPMSM) with a delta-shaped magnet array was used to improve the torque and power characteristics. A step skew rotor structure was also used to dampen vibration and noise by minimizing the high-order harmonics in the cogging torque. The proposed analysis and design approach also reduces the total harmonic distortion (THD) of the back electromotive force (EMF). The effectiveness of the proposed analysis and design process and the usefulness of the resulting high-performance traction motor for heavy-duty vehicles were verified via the finite element method (FEM) and by experiment.

Design and Analysis of PMSM Traction Motor for Passenger Car Applications

In recent years, owing to the severity of global warming and deduction in petroleum resources quicken the researches to move on sustainable energy resources. Thereby E-mobility has been picturized and fully electric vehicle technology is the major research area nowadays. This paper presents the design methodology of electric traction motor requirement by considering vehicle dynamics and passenger car parameters. Pertaining to the vehicle desired performance, the maximum optimal power is computed. Followed by that power, torque Vs speed profile is determined and the same is compared with the urban and extra-urban drive cycle to estimate the average power and torque. Then the Interior PMSM 2D Finite Element Method (FEM) analysis is planned to carry out with the geometries obtained from analytical calculations for two different slot-pole combinations. The performance differences such as torque Vs speed profile, No-load Back EMF and torque ripple are investigated.

A Fast Analysis Method of Mechanical Characteristics for Railway Vehicle Traction Motor Hanging Leaf Spring Based on Analytical Calculation

In order to analyse the mechanical characteristics of the traction motor hanging leaf spring of railway vehicles quickly and effectively, by establishing the vertical and the lateral force model of the hanging leaf spring, the mathematical model for analysing the stiffness characteristics and the stress characteristics of the hanging leaf spring were established based on analytical calculation, and the reliability of the mathematical model was verified by the loading-unloading test. The test results show that the analysis method for analysing the mechanical characteristics of the traction motor hanging leaf spring established is reliable. This research can provide a certain popularization and application value for the analysis and design of the railway vehicle traction motor hanging leaf spring.

Thermal and Manufacturing Aspects of Traction Motors Potting: A Deep Experimental Evaluation

Thermal effects and manufacturing processes of different potting strategies are studied in this paper. In the first small prototype, winding is impregnated traditionally with a standard epoxy-based material and then potted using a thermally conductive epoxy. In the motor with global potting, a single material and process is used to enhance heat transfer from the copper conductors in the winding to the housing where the cooling ducts are located. The potted motors are then compared to a reference motor without potting and impregnated using standard resins. Steady-state and transient thermal measurements are made, and a comparative investigation is performed on the built prototypes. Moreover, influence of traction motor design on thermal effects of potting is studied and presented in this paper. Using the results achieved on the tested prototypes, end winding potting is applied to a real-size traction motor designed and built for electric off-road vehicles and thermal effects are investigated in a test setup where the potted and unpotted motor are placed back-to-back running in an identical operating point and under the same cooling conditions. Additionally, measurements on specific duty cycles are run with the aim of investigating the potting thermal performance in operating condition.

A Review on Different Aspects of Traction Motor Design for Railway Applications

This article presents a review in three parts on the current traction motor topologies available in the railway market. In the first part, essential aspects of the electromagnetic design of railway traction motors, e.g., motor sizing and rotor configurations, are discussed. Different topologies are compared considering the wide range of applications. The pros and cons of each topology in specific applications are highlighted based on the corresponding performance requirements. In the second part, different cooling configurations of traction motors common in railway are reviewed, focusing on the solutions based on air cooling. The third part presents a review of the available insulation systems for traction motors. Two primary insulation systems used in traction applications with thermal classes of H and N are discussed. The focus in this article is placed on the main applications in railway including light rail vehicles, metros, electric multiple units, high-speed trains, and locomotives. Additionally, trends in traction motors development in the coming years are reported separately for electromagnetic, cooling, and insulation designs.

Behavior Study of Permanent Magnet Synchronous Machines Based on a New Normalized Model

Permanent magnet synchronous machines (PMSMs) are widely used in many applications. The performance of the PMSM is highly dependent on the motor parameters. Many research studies have been done to evaluate the PMSM performances in terms of maximum torque capability, power capability, and field-weakening capability. This paper proposes a new normalized PMSM model and uses two parameters, characteristic current and saliency ratio, to uniquely define the motor characteristic. Based on this normalized model, the full map motor behaviors, including torque capability, power capability, torque/power-speed characteristics, and power factor behaviors, are studied parametrically. A new unitless metric, i.e., copper loss factor, is introduced to evaluate the copper loss variation of PMSMs. The saturation effect on the motor behavior is studied based on the 2004 Prius traction motor, which confirms that the field-weakening characteristic can be well predicted using the linearized model. A new design flow for traction PMSMs, which requires wide-speed operation, is proposed based on the full map motor behavior study, and a prototype machine is designed accordingly. The behavior study and the effectiveness of the traction motor design flow are validated experimentally by the prototype.