Investigation and Analysis of Novel Skewing in a 140 kW Traction Motor of Railway Cars That Accommodate Limited Inverter Switching Frequency and Totally Enclosed Cooling System

This study facilitated the improvement of no-load back electromotive force (back-EMF) wave form, total harmonic distortion (THD) of back-EMF, and torque ripple using a novel skew angle formula, considering the specific order of a no-load THD. In real usage environments, it is taken into consideration for the fully enclosed cooling system and limited inverter switching frequency of urban railway car traction motors. Since the most railway car traction motors use high-withstand voltage rectangular wires in slot-open structure, a no-load back EMF waveform includes large space slot harmonics, which should be smaller as possible. For 6-step control, the no-load back EMF waveform is important because switching for motor control is performed once after the rotor position is determined. To improve the no-load back EMF waveform and THD, two-dimensional and three-dimensional finite element analysis (FEA) were performed using a novel skew angle formula considering specific harmonic order reduction, while the fundamental amplitude was minimally reduced. A prototype with the novel skew was fabricated and verified. In addition, it was designed by calculating a low current density for a fully enclosed cooling system. A temperature saturation experiment was also performed, and successfully verified. Therefore, we suggest that the no-load back EMF characteristics and torque ripple are improved by applying the novel skew angle instead of a traditional skew angle.

*Published in the IEEE Magnetics Society Section within IEEE Access.

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IEEE Magnetics Society Co-Sponsoring the 2022 Joint MMM-Intermag Conference

The IEEE Magnetics Society, which has a permanent section within IEEE Access, will be co-sponsoring the Joint MMM-Intermag Conference in New Orleans, LA, from January 10-14, 2022 with AIP Publishing LLC.  

The 15th Joint MMM-INTERMAG Conference (2022 Joint) is an opportunity for members of the international scientific and engineering communities interested in recent developments in fundamental and applied magnetism to attend and contribute to the technical sessions. The conference will offer both in-person and prerecorded on-demand content.

The technical program will include invited and contributed papers in oral and poster sessions, invited symposia, a plenary session, and an evening session, with about 1500 presentations overall. Listed below are just a few of the Special Events and Sessions occurring during the conference: 

– Tutorial: Quantum  Magnonics
– Special Session: Current Trends in Magnetism,
– Women in Magnetism Event
– Plenary and IEEE Awards Ceremony
– Writing Workshop


To learn more about attending or participating in this conference, please visit the conference website.

Agent Architecture for Adaptive Behaviors in Autonomous Driving

Evolution has endowed animals with outstanding adaptive behaviours which are grounded in the organization of their sensorimotor system. This paper uses inspiration from these principles of organization in the design of an artificial agent for autonomous driving. After distilling the relevant principles from biology, their functional role in the implementation of an artificial system are explained. The resulting Agent, developed in an EU H2020 Research and Innovation Action, is used to concretely demonstrate the emergence of adaptive behaviour with a significant level of autonomy. Guidelines to adapt the same principled organization of the sensorimotor system to other agents for driving are also obtained. The demonstration of the system abilities is given with example scenarios and open access simulation tools. Prospective developments concerning learning via mental imagery are finally discussed.

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In-Bore Dynamic Measurement and Mechanism Analysis of Multi-Physics Environment for Electromagnetic Railguns

Electromagnetic launch technology has important applications in many fields. However, the extremely harsh multi-physics environment during the launch is quite different from that of conventional guns. Little experimental research studied the dynamic distribution of the extreme impact environment and magnetic fields in the projectile. To this end, this paper designs a projectile-borne storage testing system for the dynamic measurement of harsh multi-physics environments. The detailed assessment of the measured dynamic multi-physics field shows that the velocity skin effect (VSE) is an important factor affecting the dynamic results. It causes a higher current density in the armature, and the magnetic induction and acceleration in the dynamic experiment are lower than those in the static-based experiment and simulation. Moreover, it causes the concentrated heat on the trailing edge of the armature, which lead to the melt-wave erosion, even affects the movement of integrated projectile during launch. Furthermore, the physical mechanism behind these phenomenon is revealed, and the causes of muzzle velocity error are analyzed. In conclusion, a feasible, dynamic measurement method for multi-physics coupled environments is presented, which can provide references for follow-up modeling and simulation researches and promote the development of railguns.

Published in the IEEE Magnetics Society Section within IEEE Access.

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