Velocity-Induced Current Profiles Inside the Rails of an Electric Launcher

Liebfried, Oliver; Schneider, M.; Stankevič, Tomaš; Balevičius, Saulius; Žurauskienė, N.

doi:10.1109/tps.2013.2249534

Cited by 15 publications

(5 citation statements)

References 21 publications

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“…EFFE software [6], [7] is also have the same technique, rail moves backward rather than the armature movement. Quasi-static, time-harmonic FEM are also used to model velocity induced currents [8], [9].…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

Tosun

Ceylan

Polat

et al. 2021

IEEE Trans. Plasma Sci.

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Analysis of the velocity skin effect (VSE) in electromagnetic launchers (EMLs) requires a 3-D transient finite element method, unlike magnetic skin and proximity effects. However, VSE is dominant at high speeds, and this creates convergence problems when moving or deformed mesh physics is used in a transient FEM in the 3-D analysis. Commercial finite element software cannot solve the electromagnetic aspects of such a high-speed application with a transient solver in 3-D. Although 2-D approximations can be used, such an approximation overestimates VSE resistance due to geometry simplifications. In this study, we proposed a novel quasi-transient 3-D FEM model where the air-armature region's conductivity is varied to emulate the high-speed motion of the armature. Results showed that 2-D approximation; overestimates the VSE resistance by almost 40%. The proposed VSE model has been included in the EML model, and simulation results compared for experimental results with different EMLs, EMFY-1 and EMFY-2, and showed good agreement.

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Section: Introductionmentioning

confidence: 99%

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

Tosun

Ceylan

Polat

et al. 2021

IEEE Trans. Plasma Sci.

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“…The current flowing in the rails (and in the armature) produces a flux density distribution in correspondence of the armature, where the interaction with its current produces a thrust force that accelerates the armature. The main drawbacks affecting the rail launchers are a consequence of the Velocity Skin Effect (VSE) which is caused by the limited diffusion rate of the current in the rails as the armature moves; VES produces a concentration of the current in the rear portion of the armature near the rails [15][16][17][18]. The importance of VSE increases with the speed and it is one of the causes which may prevent the use of rail launchers at very high speed.…”

Section: Introductionmentioning

confidence: 99%

“…The availability of numerical tools for the investigation of VSE and for the design of countermeasures to limit its effects on the launcher performance are of paramount importance [17,19,20].…”

Section: Introductionmentioning

confidence: 99%

Numerical 3D Simulation of a Full System Air Core Compulsator-Electromagnetic Rail Launcher

et al. 2020

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Multiphysics problems represent an open issue in numerical modeling. Electromagnetic launchers represent typical examples that require a strongly coupled magnetoquasistatic and mechanical approach. This is mainly due to the high velocities which make comparable the electrical and the mechanical response times. The analysis of interacting devices (e.g., a rail launcher and its feeding generator) adds further complexity, since in this context the substitution of one device with an electric circuit does not guarantee the accuracy of the analysis. A simultaneous full 3D electromechanical analysis of the interacting devices is often required. In this paper a numerical 3D analysis of a full launch system, composed by an air-core compulsator which feeds an electromagnetic rail launcher, is presented. The analysis has been performed by using a dedicated, in-house developed research code, named “EN4EM” (Equivalent Network for Electromagnetic Modeling). This code is able to take into account all the relevant electromechanical quantities and phenomena (i.e., eddy currents, velocity skin effect, sliding contacts) in both the devices. A weakly coupled analysis, based on the use of a zero-dimensional model of the launcher (i.e., a single loop electrical equivalent circuit), has been also performed. Its results, compared with those by the simultaneous 3D analysis of interacting devices, show an over-estimate of about 10–15% of the muzzle speed of the armature.

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“…Moreover, due to the motion between the pantograph strip and the catenary, a velocity skin effect (VSE) becomes pronounced [10, 11] and may become quite dramatic as the speed increases. The VSE is a phenomenon of current clustering observed in a region near the contact interface between two objects [12]. Owing to the VSE, the current tends to cluster at the trailing edge of the pantograph strip.…”

Section: Introductionmentioning

confidence: 99%

“…The damage to the pantograph is further aggravated by the already mentioned phenomenon of VSE, well known and thoroughly researched in the context of electromagnetic launchers, which has some similarities to the performance of PCSs, although the speeds here are not so high. Initially, VSE was observed as an asymmetric wear of recovered armatures [12]. Then, to explore its origins and properties, several VSE models were established for medium and low speeds [13, 14].…”

Section: Introductionmentioning

confidence: 99%

Multi‐physics analysis and optimisation of high‐speed train pantograph–catenary systems allowing for velocity skin effect

et al. 2020

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A pantograph–catenary system (PCS) – an essential component to supply a high‐speed train (HST) – faces a variety of new challenges due to the continuously increasing train speeds. The HST traction system receives power via an electrical contact between the pantograph strip and the high‐voltage contact wire. This electrical contact is subject to serious mechanical shocks and significant electrochemical corrosion, making the modelling of the dynamic processes complicated, especially under high‐speed and heavy‐load conditions. The damage to the PCS – which is particularly noticeable at the edges of the pantograph strip – may become severe as the speed of the train rises. Moreover, as the speed increases, the distribution of the electrical current in the strip becomes uneven due to the velocity skin effect (VSE). To assess the impact of the VSE on the performance of PCSs, a multi‐physics model has been created and is reported in this study. The model has been validated through experiments and the main aspects of its functionality – such as the VSE, friction, and air convection – have been identified and analysed at different speeds. The impact of speed on the traction current and the behaviour of thermal sources have been explored. With the increasing speed, the phenomenon of current clustering at the trailing edge of the strip becomes quite dramatic, resulting in a thermal surge in the region of the strip with high current density. To mitigate the negative impact caused by VSE in the PCSs, an improved kriging optimisation methodology has been utilised to optimise the parameters of the PCS. Recommendations regarding the optimal design of the PCS are put forward to improve the current‐carrying performance and reduce the local temperature rise in the strip.

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Velocity-Induced Current Profiles Inside the Rails of an Electric Launcher

Cited by 15 publications

References 21 publications

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

Numerical 3D Simulation of a Full System Air Core Compulsator-Electromagnetic Rail Launcher

Multi‐physics analysis and optimisation of high‐speed train pantograph–catenary systems allowing for velocity skin effect

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