Development and research of bidirectional step-down AC-AC-DC converter for AC electric locomotive

Modular multilevel converter based topology for electric locomotive with medium frequency step-down transformer

IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society ◽

10.1109/iecon.2018.8592750 ◽

2018 ◽

Author(s):

Bishwajyoti Purkayastha ◽

Tanmoy Bhattacharya

Keyword(s):

Modular Multilevel Converter ◽

Electric Locomotive ◽

Multilevel Converter ◽

Medium Frequency ◽

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Power supply for a CIP position for bearings

Proceedings of Petersburg Transport University ◽

10.20295/1815-588x-2021-4-554-560 ◽

2021 ◽

Vol 2021 (4) ◽

pp. 554-560

Author(s):

Alexey P. ZELENCHENKO ◽

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Anton A. BOGDAN ◽

Murodilla Sh. SHADMONKHODZHAEV ◽

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...

Keyword(s):

Power Supply ◽

Practical Importance ◽

Motor Units ◽

Electric Locomotive ◽

Power Sources ◽

Traction Motors ◽

Bearing Diagnostics ◽

Three Phase ◽

Pulse Converter ◽

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Objective: Two possible options for power sources are considered: a controlled three-phase bridge rectifi er circuit with a step-down transformer and a pulse converter receiving power from the network through an uncontrolled three-phase bridge rectifi er to drive the wheel-motor units of electric locomotives and electric trains into rotation with the required frequency at the position of CIP bearing diagnostics. In both cases, it is assumed that the power supplies receive electricity from the 380/220 V, 50 Hz network. The power source is loaded with traction motors of the ER2R, ER2T, ET2, ET2M electric trains and the VL-10 electric locomotive. Methods: Mathematical modeling is used in the MatLab/Simulink environment for analytical calculations. Results: The currents and voltages of the load were determined, based on the calculations, the control angles and power factors of the rectifi er with a step-down transformer, the duty cycle of the pulse converter. Practical importance: A variant of an energy-effi cient power supply is proposed, including an uncontrolled rectifi er and a pulse converter.

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Rem Study of Current Effect on the Structure of Clean Si(111) Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180288 ◽

1990 ◽

Vol 48 (1) ◽

pp. 306-307

Author(s):

A. Yamanaka ◽

H. Ohse ◽

K. Yagi

Keyword(s):

The Other ◽

Current Direction ◽

Clean Surface ◽

Current Effect ◽

Atomic Steps ◽

Step Bunching ◽

Terrace Width ◽

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A Current

Recently current effects on clean and metal adsorbate surfaces have attracted much attention not only because of interesting phenomena but also because of practically importance in treatingclean and metal adsorbate surfaces [1-6]. In the former case, metals deposited migrate on the deposit depending on the current direction and a patch of the deposit expands on the clean surface [1]. The migration is closely related to the adsorbate structures and substrate structures including their anisotropy [2,7]. In the latter case, configurations of surface atomic steps depends on the current direction. In the case of Si(001) surface equally spaced array of monatom high steps along the [110] direction produces the 2x1 and 1x2 terraces. However, a relative terrace width of the two domain depends on the current direction; a step-up current widen terraces on which dimers are parallel to the current, while a step-down current widen the other terraces [3]. On (111) surface, a step-down current produces step bunching at temperatures between 1250-1350°C, while a step-up current produces step bunching at temperatures between 1050-1250°C [5].In the present paper, our REM observations on a current induced step bunching, started independently, are described.Our results are summarized as follows.(1) Above around 1000°C a step-up current induces step bunching. The phenomenon reverses around 1200 C; a step-down current induces step bunching. The observations agree with the previous reports [5].

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