Publications associées à Speed and Stability Limits for High-Speed Bearingless Disc Drives

Laser Doppler Vibrometer measurements of the 3D pressure field for the estimation of the radiation force produced by an acoustic standing-wave levitator

Acoustic levitation devices use powerful ultrasonic standing waves to levitate objects in mid-air. We have created a system and method to measure the full harmonic content of the acoustic field accurately. Our study revealed that levitated particles alter ...

Elsevier Science Sa2024

Modelling and Sensors for Magnetically-Levitated Disc Drives

Juan Patricio Tomás Peralta Fierro

The development of new industrial applications has diverted the focus of research towards compacter and faster rotatory drives. These requirements push the classical ball-bearings of electric motors to the limits in terms of operational lifetime and fricti ...

EPFL2022

Principles and Test Result of Novel Full Passive Magnetic Levitation Motor with Diamagnetic Disk

Hannes Bleuler

This paper proposes a novel full passive magnetic levitation motor without active magnetic suspension. It has a magnetic levitation unit and a motor unit. The Halbach array permanent magnets and a pyrolytic graphite (PG) disk realize the full passive magne ...

IEEE2021

Characterization and Verification of Eddy-Current Position Sensing for Magnetic Levitation

Yves Perriard, Sean Thomas, Juan Patricio Tomás Peralta Fierro

Magnetically-levitated drives are compelling in applications where the long-lifetime operation or process chamber encapsulation is a requirement. To exploit these advantages, contactless position sensors are needed to estimate the position of the rotor. Of ...

2021

Controlling the rotation of drift tearing modes by biased electrode in ADITYA-U tokamak

Sameer Kumar, Abhijit Sen, Harshita Raj, Ankit Kumar, Rohit Kumar

The influence of background plasma poloidal rotation on the rotation frequency of the m/n = 2/1 drift tearing mode (DTM) has been studied in ADITYA-U tokamak. The poloidal rotation velocity of the background plasma in the ion diamagnetic direction is incre ...

2021

Experimental verification of X-point potential well formation in unfavorable magnetic field direction

Basil Duval, Holger Reimerdes, Marco Wischmeier, Joaquim Loizu Cisquella, Christian Gabriel Theiler, Hugo De Oliveira, Cedric Kar-Wai Tsui, Mirko Wensing, Sophie Danielle Angelica Gorno, Claudia Colandrea

Recent TCV experiments confirm the predicted formation of an electric potential well, below the magnetic X-point, in configurations with unfavorable

B_t

field direction (ion

\nabla B

drift away from the divertor), that substantially reshapes the typica ...

Elsevier2020

Design of Compact Bearingless Disc Drive Systems

Yves Perriard, Douglas Martins Araujo, Juan Patricio Tomás Peralta Fierro

Inflating costs and emerging applications are spawning interests toward smaller and faster electric drives. The challenges of miniaturization make magnetic bearings more appealing, as they provide intrinsic high-speed capability and need virtually zero-mai ...

2020

Transient Electronics for Smart Biodegradable Medical Implants

Matthieu Jean Michel Rüegg

Bioresorbable implantable medical devices show great potential for applications requiring medical care over well-defined periods of time. Such implants naturally degrade and resorb in the body, which eliminates adverse long-term effects or the need for a s ...

EPFL2020

Magnet-assisted ball drive

Francesco Mondada, Pierre Dillenbourg, Séverin Lemaignan, Ayberk Özgür, Wafa Monia Benkaouar Johal

The present invention concerns a magnet-assisted ball drive. The drive comprises a ball and a drive element in contact with the ball. The drive element is arranged to be rotated around its axis of rotation to drive the ball. The ball and the drive element ...

2019

Diamond Window Technology for Electron Cyclotron Heating and Current Drive: State of the Art

Konstantinos Avramidis

Nuclear fusion power plants require electron cyclotron (EC) heating and current drive (H&CD) systems for plasma heating and stabilization. High-power microwave beams between 1 and 2?MW generated by gyrotrons propagate in a dedicated waveguide transmission ...

TAYLOR & FRANCIS INC2019

Method and Procedure in Metal Detection and Distinctive Discrimination of Size, Shape, and Location of Hidden Single and Multi-Material Targets

Chafic Abu Antoun

This work provides a procedure and methodology for the design of an electro-magnetic sensor based on induction due to ferromagnetic and pure electrically conduc-tive hidden targets. The electromagnetic sensor is made of one or several excitation coils, whi ...

EPFL2017

Acoustic emission source detection and wave generation on a working plate using piezoelectric actuators

Xinchang Liu

In modern automated assembly lines, part feeders play an important role to separate and sort parts. Agility and flexibility are required to achieve a good yield for different types of parts. The common working principle is to vibrate a working plate driven ...

EPFL2017

Stabilization of electrodynamic bearings with active magnetic dampers

Qingwen Cui

Electrodynamic Bearings (EDBs) are a kind of passive magnetic bearings that exploits the interaction between the induced eddy currents in a conductor and a magnetic field to provide re-storing forces. They have been regarded as an appealing alternative to ...

EPFL2016

Multiport Resonant DC-DC Converter

Philippe Barrade, Yan-Kim Tran, Drazen Dujic

his paper presents a multiport galvanically isolated LLC resonant DC-DC converter suitable for DC applications. A three-port structure is analyzed, with full bidirectional power flow capabilities, simple control and behavior similar to that expected from a ...

2015

A dual-axis pointing mirror with moving-magnet actuation

Nico de Rooij, Wilfried Noell, Caglar Ataman, Sébastien Lani

A large-aperture and large-angle MEMS-based 2D pointing mirror is presented. The device is electromagnetically actuated by a moving-magnet/stationary-coil pair and potentially suited for high power laser beam shaping and beam pointing applications, such as ...

Institute of Physics2013

Electromechanically induced absorption in a circuit nano-electromechanical system

Tobias Kippenberg, Xiaoqing Zhou, Albert Schliesser

A detailed analysis of electromechanically induced absorption (EMIA) in a circuit nano-electromechanical hybrid system consisting of a superconducting microwave resonator coupled to a nanomechanical beam is presented. By performing two-tone spectroscopy ex ...

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2012

Advanced Model for Multiphase Generators

György Atilla Bànyai

The current development of generators and power electric drives is characterized by increased power electronic integration. This evolution concerns particularly the variable speed power units allowing both a higher performance and substantial savings on co ...

EPFL2011

Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

Federico David Halpern

The cycling dynamics of the internal kink mode, which drives sawtooth oscillations in tokamak plasmas, is studied using the three dimensional, non-linear magnetohydrodynamic (MHD) code XTOR-2F [H. Lütjens and J.-F. Luciani, J. Comput. Phys. 229, 8130 (2010 ...

American Institute of Physics2011

Large Hybrid High Precision MEMS Mirrors

Dara Zaman Bayat

This thesis presents the design and microfabrication technology of a tip-tilt, 2 degree of freedom "mirror system" made out of Silicon On Insulator (SOI) wafers with two movable mirrors that have diameter of 10 mm. The system was intended for precise beam ...

EPFL2011

Forced and Self Oscillations of Hydraulic Systems Induced by Cavitation Vortex Rope of Francis Turbines

Sébastien Alligné

With economical energy market strategies based on instantaneous pricings of electricity as function of the demand or the predictions, operators harness more hydroelectric facilities to off-design operating points to cover the variations of the electricity ...

EPFL2011