Traction Motor Research Articles

Study on Cage Wear of Railway Traction Motor Bearings Based on Analysis of Rolling Element Motion

Cylindrical roller bearings used in traction motors for railway vehicles are used at high rotational speeds and under light loads. Under these operating conditions, the life due to cage wear is much shorter than the life due to raceway fatigue. Therefore, bearing life can be extended by reducing cage wear. The authors thought that to reduce cage wear, it is necessary to establish a dynamic analysis method for the contact between the roller and the cage, and to identify the wear mode of the cage. If cage wear follows Archard’s equation, then cage wear is proportional to the impulse caused by the contact between the rollers and the cage. Therefore, in this paper, a simple model consisting only of a roller and a cage was constructed, and the impulse was obtained via dynamic analysis. The impulses calculated by the dynamic analysis were in good agreement with those measured. In addition, the experiments showed that cage wear is proportional to the impulse and revealed the wear mode of the cage. These allow the method proposed in this paper to be used to predict cage wear and to determine bearing specifications to reduce cage wear.

Whole body vibration and rider comfort determination of an electric two-wheeler test rig

Background: Two-wheeled vehicles are the major mode of transportation in India. Such vehicles are exposed to excessive vibration on the road when compared to four-wheeled vehicles. However, the research on the reduction of whole body vibration in the case of two-wheelers is not explored in detail. The present study predicts rider comfort in the case of an electric two-wheeler as per ISO 2631-1. Methods: An electric two-wheeler test rig is used in the study. The values of acceleration from the test rig in running conditions are obtained by using NI LabVIEW 2016. The drive cycle of the electric vehicle (EV) test rig is controlled by Sync sols’ EV lab software. Obtaining the root mean square (RMS) acceleration from running the test setup, it is compared with the ISO 2631 standard to obtain the rider comfort. Results: Loading area, traction motor, base mount, and suspension were found to be the strategic points of vibration. RMS acceleration of 0.2 g to 3.29 g obtained at these points are prone to cause discomfort for the rider. Vehicle speed, road profile, and duration of exposure were found to be important parameters affecting the rider’s comfort. About 19 % increase in the vibration amplitude is observed at the loading area when loads are removed. The loading area as corresponds to a rider’s seat in actual vehicle, it is important to reduce these vibrations to make the ride comfortable for the rider. Conclusions: A suitable damping technique design is very much essential in reducing these vibrations and improve the rider comfort, as many more non-deterministic vibrations are prone to cause dis-comfort in case of actual on road riding conditions.

Optimal design of a 15 kW-class interior permanent magnet synchronous motor for micro-EV traction using artificial neural network models

Optimal design of a 15 kW-class interior permanent magnet synchronous motor for micro-EV traction using artificial neural network models

Inverter Power Device Fault Detection and Fail Safe Action Strategy for Electric Vehicle With a Dual Inverter Fed Open Winding Motor

A electric vehicle (EV) needs high drive system efficiency, low motor noise and limp-home capability of the traction drive when there is a component failure. A dual inverter fed open winding interior permanent magnet synchronous motor (DIF-OW-IPMSM) drive system satisfied all the above needs. In this paper, new algorithms for the inverter power device fault detection and fail-safe action strategy for the DIF-OW-IPMSM drive system in the entire speed region of the EV are proposed to prove its high reliability. The new algorithms for the inverter power device fault detection are derived from the sensed three phase fault currents and their subsequent analytical and logical processing within the micro-computer. The fail-safe action strategy is derived such that the unbalanced three phase fault currents using the dual inverters are quickly restored to balanced three phase currents using a single inverter and hence, the effect of the vibration of the traction motor due to undesired torque ripple during inverter device fault condition is kept minimum. The proposed new algorithms are verified by suitable simulation and experimental results, and the safe limp-home capability of the DIF-OW-IPMSM drive system is demonstrated.

An adaptive receding horizon-based flexible mode switching control strategy of parallel hybrid electric vehicles

Mode switching is crucial to efficient drive in variable driving conditions for hybrid electric vehicles (HEVs), thus many scholars are attracted to implement its high-quality control. The receding horizon control method is an attractive method to solve this problem. However, the choice of prediction horizon is arduous due to the contradiction between the optimization performance and the computational cost. Motivated by this issue, this paper proposes an adaptive receding horizon control (RHC) method, which contains optimization layer (OPL) and feedback control layer (FCL). First, an OPL adaptive receding horizon control method is proposed to obtain the optimal control command, in which a novel adaptive factor, considering the proportional between the maximum traction motor torque and powertrain demand torque, is proposed to adjust the prediction horizon length and control constraints. Then, regarding OPL output as the reference trajectory, a lower-RHC method is designed in FCL to track the reference trajectory. Finally, the proposed control method is validated in simulation and bench experiment. Compared with the existing method, the clutch trajectory is optimized by RHC with adaptive prediction horizon and constrains, and the anti-disturbance ability is enhanced by the lower-RHC. The simulation and bench experiment results indicate that the 0–40 km/h acceleration time and jerk are reduced using the proposed method, respectively.

Operational Diagnostics System for Asymmetric Emergency Modes in Traction Drives with Direct Torque Control

This article presents an analysis of the causes behind the development of asymmetric modes in a traction drive system that features direct torque control (DTC) of a rolling stock with asynchronous traction motors. The development of asymmetric modes in the traction drive system was found to be caused by the asymmetry of the supply voltage system, the asymmetry of the traction motor windings, and transient processes triggered by a change in the inverter supply voltage and variation in the traction motor load. At the same time, the asymmetric modes caused by the asymmetry of the feed voltage system and the windings of the traction motor are the emergency modes. The influence of the asymmetry of the feed voltage system and asymmetry of the windings of traction motor on the starting characteristics of the phase currents and flux linkages of the stator in the steady-state mode was investigated. In these cases, the ratio of the amplitudes of phase currents and flux linkages of the stator of different phases was found to be constant. The effect of a variation in the feed voltage and load acting on the motor shaft on the starting characteristics of phase currents and flux linkages of the stator was investigated in the case of absence of the emergency modes. In these cases, the ratio of the amplitudes of phase currents and flux linkages of the stator of different phases was found to not be constant. The amplitudes of the phase current and stator flux linkage were proposed as criteria for diagnosis and identification of asymmetric emergency modes. An algorithm and a structural scheme have been proposed for the diagnosis of emergency asymmetric modes in the traction drive system with direct torque control. Modifications to the traction drive system with direct torque control are suggested in order to diagnose the presence of faulty asymmetric modes and identify the damaged traction drive element.

DC-link oscillation suppression method based on q-axis voltage compensation of a 180 kW PMSM traction system for urban rail transit

Under certain working conditions, the permanent magnet synchronous motor (PMSM) traction system of urban rail transit shows negative impedance characteristics, which is easy to cause voltage resonance of DC-link and lead to instability of the system. In order to ensure the stability of the system, a DC-link oscillation suppression method based on q-axis voltage compensation is proposed. Firstly, the PMSM traction system and oscillation mechanism of DC-link are analyzed. Secondly, a stable control method based on q-axis feedforward decoupling voltage compensation is adopted to realize the decoupling control of PMSM and the suppression of DC-link oscillation. Finally, the method is verified on a 180 kW PMSM traction system, simulation and experiment verify the effectiveness of the DC-link oscillation suppression method.

Fuzzy adaptive PID speed controller design for modern elevator traction machine

With the development of the times, elevator has become an essential transportation in our life. In order to meet the comfort of elevator operation, this paper investigates the design of the speed control system of elevator permanent magnet synchronous traction motor in combination with the elevator operation curve. The whole system is based on SVPWM and uses direct torque control combined with fuzzy adaptive PID to achieve accurate control of motor running speed. It includes the input signal module, control module, drive module and feedback module. Firstly, the analysis of each module in the system is completed, and the connection between the modules is established, as well as the control system. Then case studies are carried out on MATLAB/SIMULINK, and the actual running speed curve of the elevator is obtained, and the simulation results are analyzed to verify the stability and reliability of this speed control system and complete the design.

Analysis of the Efficiency of Traction Drive Control Systems of Electric Locomotives with Asynchronous Traction Motors

An analysis of the operating conditions of the traction drives of an electric rolling stock with asynchronous traction motors was conducted. In the process of operation, the electric traction drive with both direct torque control and vector control was found to possibly experience unstable modes, both in terms of power supply and load. The models of electric locomotive traction drives with asynchronous electric motors with either vector or direct torque control were adapted to account for the possible presence of the aforementioned operational factors. As a result of the modeling, the starting characteristics of the electric traction drives with different control systems were obtained both in the absence and in the presence of power supply and load disturbances. The following cases were investigated for the drive with vector and direct torque control in the absence of power supply and torque disturbances: drive output at the rated speed of rotation of the electric motor shaft; 10% reduction in the rated speed; 10% increase in the rated speed. The comparison of the results obtained has demonstrated that, at lower than nominal frequencies, the electric traction drive with direct torque control has higher accuracy in its regulation of the rotational speed and torque, lower power consumption from the power supply, lower torque overshooting, but a higher level of torque pulsations than the electric traction drive with vector control. Meanwhile, at higher than nominal frequencies, the vector control has higher accuracy in its regulation of the speed, lower torque overshooting, shorter duration of transient processes, and lower torque pulsations than the direct torque control. Moreover, as a result of the investigations, the traction drive with direct torque control has been found to be more resistant to power supply and load disturbances. The results of this work are applicable to the investigation of the influence of electric traction drive control methods on the energy efficiency of the traction drive of an electric locomotive with an alternating current (AC).

Composite fault diagnosis of traction motor of high-speed train based on support vector machine and sensor

Composite fault diagnosis of traction motor of high-speed train based on support vector machine and sensor

Development of a Novel High Strength Aluminum-Cerium Based Rotor Alloy for Electric Vehicle Induction Motor Applications

<div class="section abstract"><div class="htmlview paragraph">To increase vehicle range, light weighting of electric vehicles has been extensively researched and implemented by using aluminum intensive solutions. With regards to traction motors, aluminum alloys that have a desired combination of high electrical conductivity and strength are required for high power output and efficiency. In this research, a novel Al-Ce based alloy, with minor additions of Si and Mg for strengthening, was investigated in different heat treatment tempers to maximize mechanical properties while maintaining a high electrical conductivity. This new alloy system appears to have addressed the classic conundrum of the inverse relationship of mechanical performance verses electrical conductivity for traditional aluminum alloy systems. The results suggest that the Al-Ce-Si-Mg alloy had yield strength in excess of 120 MPa and electrical conductivity of at least 50 %IACS in the T5 and T6 conditions. Simulations of a squirrel cage induction machine show that this combination of properties resulted in similar motor performance to other rotor Al alloys. As a result, the Al-Ce-Si-Mg alloy is a promising alternative to the near pure Al or Cu-based alloys that are currently used in induction motor rotor castings.</div></div>

INCREASING THE ENERGY EFFICIENCY OF ELECTRIC DRIVES OF SUBWAY CARS

The article proposes the use of a frequency-controlled drive for regulating asynchronous electric motors used on subway cars. The proposed solution creates all the grounds for increasing the energy efficiency of electric cars and, in general, the entire metro. Taking into account that the subway is one of the most used types of urban transport in large cities of Ukraine and at the same time consumes a significant part of electricity, therefore, in the conditions of rising prices for energy resources, these issues become the most urgent. It is shown that the methods of regulation of subway engines are not covered widely enough in scientific research, but the methods of increasing the energy efficiency of drives generally accepted in industrial spheres are a developed direction. This reveals the possibilities of integrating the developed methods for application on subway cars. The use of a frequency converter, which changes the frequency of rotation of the motor rotor by changing the frequency and amplitude of the supply voltage using vector and scalar control, is a generally accepted method of motor regulation. There are a number of conflicting findings in research regarding the use of scalar or vector control, with some favoring the induction vector control system. However, a clear regulation is not required to regulate the operation of metro engines. Therefore, the article considers scalar control, which has not lost its importance due to the ease of implementation and adjustment and is used in various areas of industry and transport. The parameters of the STDa 280-4B-UK type STDa 280-4B-UK traction asynchronous traction motor with a capacity of 180 kW, manufactured by the EMIT Cantoni Motors company, which are installed on subway cars of the 81-7036/7037 series, were used for the study. The parameters of the T-substitution scheme of the asynchronous electric drive and the numerical values of the vectors of the asynchronous motor were calculated. To analyze the operation of an asynchronous motor, the article uses the mechanical characteristic of the dependence of the motor torque on slippage at certain frequency values. It has been established that an asynchronous motor can operate stably only in a limited slip range, when the moment reaches its maximum value and the motor stops, as it has a load limit. The main reason for this is the increase in the influence of the active resistance of the stator winding when the supply voltage frequency decreases. The solution to this problem is the introduction of IR-compensation into the control system of the electric drive, which provides positive feedback on the stator current acting in the voltage channel. To demonstrate the effect of IR compensation, a comparison of mechanical characteristics was made before and after its introduction into the control system. Therefore, it was proved that the application of IR compensation is a promising direction of work, as the value of the electromagnetic moment increases significantly in the case of a low control frequency. Keywords: energy efficiency, asynchronous electric motor, subway, electric drive, scalar control, IR compensation.

Fault-Tolerant Control for a Six-Phase Two-Controllable-Rotor Motor

A number of transport vehicles have been fitted with electric traction motors and their inverters. The traction motor is required to continue to operate even if the inverter is under fault conditions. We propose a motor with two controllable rotors for a traction motor, which consists of two rotors and one stator. In this article, we propose a fault-tolerant control method for a two-controllable-rotor motor using a six-phase inverter. The operational principle of the two-controllable-rotor motor is described. The mathematical model under fault-tolerant control is shown, and a fault-tolerant control method for the two-controllable-rotor motor is described. The proposed fault-tolerant control method is verified by conducting finite element analysis (FEA) and carrying out measurements on a prototype.

Compressed Sensing of Traction Motor Bearing Vibration Signals based on Discrete Fourier Transform and Generalized Orthogonal Matching Pursuit Algorithm

For the bogie traction motor bearings of rail vehicles under road transportation conditions, its vibration signal full-time domain data acquisition data volume, storage pressure, subsequent data analysis difficulties, and other problems. This study proposes a data compression acquisition and data reconstruction method for bearing vibration signals based on compressed sensing (CS), which can achieve compressed sampling, transmission, and storage of the original signal with fewer observations, and restore the original signal by combining reconstruction algorithms to achieve low error reconstruction. We study the effects of different sparse transform methods on signal sparsity, as well as the signal sparse performance based on different sparse transforms and the signal reconstruction effect of different reconstruction algorithms, and propose a sparse representation method based on the discrete Fourier transform (DFT) and the generalized orthogonal matching pursuit (gOMP) algorithm for CS. Through simulation and experimental comparison, it is concluded that the method can restore and reconstruct the original high-dimensional signal with small reconstruction error, and solve the problems of massive data, inconvenient transmission, and difficult data analysis in engineering.

Design and optimization of an external-rotor switched reluctance motor for an electric scooter

In order to reduce the global carbon foot print, the need of the hour is to provide pollution free and economically viable electric vehicles (EVs) as potential alternatives to the conventional ones. Amongst the different traction motors employed in EVs, switched reluctance motors (SRMs) being magnet-free, rugged in construction and fault-tolerant is a potential forerunner for automotive applications in the near future. Therefore, in this work, an external-rotor (ER) SRM has been designed for an electric scooter application. The proposed 4-phase SRM configuration comprises of 8 and 10 poles on the stator and rotor respectively. To achieve a well-balanced design with due consideration to the various performance indicators, a multi-objective design optimization (MOO) has been performed using particle swarm optimization (PSO). The optimization was based on the results obtained from the two-dimensional (2D) electromagnetic static finite element analysis (FEA) which aimed to maximize average torque, efficiency and minimize torque ripple respectively. In comparison to the preliminary design, the optimized ER-SRM demonstrated an increased average torque and decreased copper loss by 3% and 14% respectively. The large scale of simulations performed and the results thereby obtained confirmed that the proposed SRM design met the performance demands of the electric scooter application. The average torque at the rated and the maximum speed exceeded the desired torque requirements demanded by the electric scooter by 13.1% and 42.2% respectively.

Fixed-Time and Fault-Tolerant Path-Following Control for Autonomous Vehicles With Unknown Parameters Subject to Prescribed Performance

With the consideration of actuator faults, including the unknown steering mechanism misalignments and motor traction losses, this article presents a fixed-time control protocol to follow reference paths and velocities for autonomous ground vehicles (AGVs) with preset performance constraints. To provide sufficient large boundaries for the initial states, the hyperbolic tangent function is employed to predefine the constraints with respect to the path-following and velocity control performance. Based on the homeomorphic mapping and barrier Lyapunov theorem, the fixed-time prescribed performance control (PPC) objective-integrated fault-tolerant scheme can be achieved for the controlled AGV. In comparison to three different fixed-time controllers without the fault-tolerant or PPC scheme, the hardware-in-the-loop (HIL) test results demonstrate that the proposed control protocol can always provide superior control performance for the AGV under various maneuvering conditions.

트랙션용 다자유도 구형 전동기의 구동을 위한 간접 벡터 제어 연구

The multi-degree-of-freedom spherical motor for traction has characteristics of rotation and steering. Although it is base on the rotation principle of an induction motor, only a spherical motor control method is required for rotation and steering. In order to estimate the speed command of the rotor, the mechanical angular velocity of the rotor is measured using an optical sensor, and the slip angular velocity is calculated with the current command of the d-q axis stator of the synchronous coordinate system. The rotor magnetic flux angle can be obtained in the above two ways, and through this, the vector control of the spherical motor is achieved. The desired magnetic flux component current and torque component current are distributed to operate the spherical motor. As such, the indirect vector control method has advantages in that it is simple to implement because it does not use the magnetic flux linkage of the rotor and that it is easy to operate from low speed to rated speed.

Investigation on performance evaluation of electric vehicle batteries under different drive cycles

The drive cycles influence the design, sizing, rating, and selection of electric vehicle components. So, it is required to test the Electric Vehicle (EV) on different standard drive cycles in the simulation environment before testing in real-time to evaluate the life cycle and determine the efficient and economical design of the EV. Different standard driving cycles are available to evaluate the performance of the EVs, but these drive cycle patterns vary from country to country due to differences in road conditions, traffic density, and driver disciplines. The range and performance of the EV battery mainly depend on its cell chemistry. In this research paper, the performance of different EV batteries on various standard international and Indian drive cycles has been evaluated. To determine the performance of the EV battery, an EV drive train test system has been developed, Nissan leaf 2018 EV model data has been taken in this paper. FOC control strategy for PMSM traction motor has been developed. To reduce the harmonics and improve quality of the switching losses, Space Vector Pulse Width Modulation (SVPWM) algorithm has been adopted for PWM Inverter. Battery energy consumption, and cost per charge based on the distance travelled by the vehicle are calculated for comparing different EV batteries to evaluate their performance.

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.

In Depth Analysis of Power Balance, Handling, and the Traction Subsystem of an Articulated Skid-Steering Robot for Sustainable Agricultural Monitoring

This paper reports on the energy balance test performed on Agri.Q, an eight-wheel articulated robot intended to be a sustainable monitoring tool within the precision agriculture paradigm, and proposes an in-depth analysis of the traction subsystem in order to develop an appropriate traction allocation strategy to improve navigation through hilly or mountainous crops. Tests were conducted on the contribution of the orientable photovoltaic panel to the mission duration and overall sustainability, showing that a suitable mission plan, including dedicated charging phases, could significantly increase the robot’s operating time. A series of simulations of circular trajectories of different curvature and at different longitudinal velocities on flat ground were performed, with the aim of mapping the robot’s behaviour at steady state. The results of the simulations were analysed, paying particular attention to the required torques, manoeuvrability and forces exchanged on the ground. The simulations conducted demonstrated and extended previous results obtained on similar robotic architectures, which suffer from significant understeer behaviour due to significant lateral wheel slip during turning. They also showed the limitations of currently employed traction motors, but also the advantages of a proper traction allocation strategy involving the rear module.Article highlights.Agri.Q energy balance tests have been carried out to assess its endurance and sustainabilityThe traction and handling behaviours of Agri.Q were mapped and discussed in detail in order to improve themAgri.Q has proven to be a basis for the future implementation of precision agriculture to advance the SDGs