presented by:
NIVEETH C

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Zero power magnetic levitation using composite of magnetostrictive - piezoelectric materials
overview
Introduction
What is a composite?
• Composite for magnetic force control
• comparison
• Experiments
using composite only
using composite and electromagnet
Magnetic levitation
• Inverse magnetostrictive effect
• Joule loss
• Zero power consumption during stationary
• Control by the integral feedback
• What is a composite?
• Composite for magnetic force control
• Dimensions
Working…
• When voltage is increased with fixed gap,flux changes as in (b)
• Now the PZTs extends and reduces the compressive force on Terfenol-D
• Thus magnetic force increases
• Since flux is conserved increase of flux in terfenol cause decrease in the gap
• COMPARISON OF ELECTROMAGNET WITH COMPOSITE
ELECTROMAGNET
• It consists of coil with large no of turns of winding requires large power supply with high voltage.
• The operation is accompanied with joule loss
• Even when equipped with permanent magnet,the zero power is only valid at equilibrium state.
COMPOSITE
• It does not require large power supply because stack PZTs provide maximum performance at rating voltage.
• Power supply should amplify the voltage,but does not have to be capable of providing large current.
• The composite does not consume electric energy in static operation at any value of force.This is due to capacitive property of PZTs.
• Levitation using composite
• Yoke equations
• F = Fo + dF= Fo + Kx *x +Kv*v
Kx-gradient of F with gap under fixed voltage
Kv-gradient of F with voltage under fixed gap
• Kinetic equation
mx·· +cx· +Kx*x +Kv*v =0
c-damping coefficient
• Combination of composite and electromagnet
Experimental set up
Working
• Control voltage is fed to PZTs from gap sensor through dc-dc converter
• To electromagnet through current amplifier
• Converter is energized with a dry cell of 4.5v
By varying the gap stationary under the fixed mass, the control outputs for electromagnet and composite are
ic = Kpc *x + Kdc*x·+ Kic∫ic dt
vp= Kpp*x + Kip ∫x dt
• conclusion
• Experiments on levitation was conducted and the gap at the levitation was successfully controlled by the voltage of the PZTs
• It maintained zero power consumption in static state
• Composite can be used for large loads too
• Applications include high precision positioning and convey system
• reference
• T. Ueno, J. Qiu, and J. Tani, “Magnetic force control based on the inverse magnetostrictive effect,” IEEE Trans. Magn., vol. 40, no. 3, pp.1601–1605, May 2004.
• T. Ueno, J. Qiu, and J. Tani, “New magnetic force control device with composite of giant magnetostrictive and piezoelectric materials,” IEEE Trans. Magn., vol. 39, no. 6, pp. 3534–3540, Nov. 2003.
• T. Ueno and T. Higuchi, “Design of magnetostrictive/piezoelectric laminate composite for coil-less magnetic force,” IEEE Trans. Magn. vol. 41, no. 4, pp. 1233–1237, Apr. 2005.
• T. Ueno and T. Higuchi, “Zero-power magnetic levitation by magnetic force control device using lamination of magnetostrictive material and piezoelectric material,” in Ninth Int. Symp. Magnetic Bearings, 2004.