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Novel Method for Driving the Ultrasonic Motor

Presented bySamar Rizwi 48Waseeullah khan 47Malik Faheem 46

Group 8

A.M.U.

2 Content

1. Introduction

2. Construction

3. Principle

4. Driving method

5. Advantage & disadvantage

6. Application

7. Summary

3 Ultrasonic Motors

A device that convert electrical energy to mechanical energy.

It was invented by V.V.Lavrinko in 1965

Belongs to a class of piezoelectric motors.

Because of its advantage , USM fills a gap in certain motor and actuator.

Operating frequency is 98 kHz

4 Need for Novel Driving Method

Conventional method of driving E.M. motors ,widely suffer from several disadvantages.

1. Noisy operation

2. Electromagnetic interference

3. Magnetic losses

4. Low p.f.

5. Lesser efficiency

5Construction

1. Actuator

2. Stator

3. Rotor

4. Casing

6 Principle of Operation

Converse piezoelectric effect• When an AC voltage is applied across the terminals of piezoelectric material it shows compression and elongation

Piezoelectric effect

7 WORKING

8 Driving Method

Conventional method

Electromagnetic Transformer

Complicated circuit components

Novel method

Piezoelectric Transformer

Simplified circuit

Oscillator Phase shifter Amplifiers Frequency control circuit

9 Piezoelectric Transformer

• consists of a hard PZT (Lead Zirconium Titanate ) disc• Same size as of stator• electrode on one side is divided into two parts• Resonance frequency is given by

E= Young modulus ɑ= radiusσ= Poissons’s ratio ρ= density

operating frequency range= 95 kHz to 110 kHz

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11 Driving System

• input power source is from a 12 VDC power supply

• Under the resonance condition of the R-L-C network:

• Under the resonance condition of the R-L-C, the matching inductor L2 satisfies:

𝜔0=𝑟𝑒𝑠𝑜𝑛𝑎𝑛𝑐𝑒𝑎𝑛𝑔𝑢𝑙𝑎𝑟 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦

𝐶0𝑇=𝑠𝑡𝑎𝑡𝑖𝑐𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑎𝑛𝑐𝑒𝑜𝑓 h𝑡 𝑒𝑝𝑖𝑒𝑧𝑜𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐 𝑡𝑟𝑎𝑛𝑠𝑓𝑜𝑟𝑚𝑒𝑟

𝐶0 𝑀=𝑠𝑡𝑎𝑡𝑖𝑐𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑎𝑛𝑐𝑒𝑜𝑓 h𝑡 𝑒𝑝𝑖𝑒𝑧𝑜𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑚𝑜𝑡𝑜𝑟 .

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13 Advantages

High o/p torque & efficiency

High power to weight ratio

Good positioning accuracy.

No magnetic interference

Small size, light weight, less noise.

14 Disadvantages

Requires high frequency power supply(kHz range).

Piezoelectric material is expensive.

Drooping torque-speed characteristics

Alternating stresses in the ceramics material might cause fatigue

failure

15 Applications

Auto focusing & optical zooming in digital

cameras & surveillance cameras.

Wrist watches & Clocks.

Power steering, Power windows, Tilt steering,

ORVM, Car seat adjustment etc.

Robotics.

Aerospace.

Hardware positioning (Hard disks, Floppy & CD

Drives) etc.

16 Summary

This paper was on novel method for driving the ultrasonic motor.

A compact disc type piezoelectric transformer is used to obtain a HV output for driving the USM.

Maximum speed obtained by using this method was above 300rpm

This study let to the integration and miniaturization of USM and its driving circuit.

17References

Hyeoung woo Kim, Shuxiang Dong, Pitak Laoratanakul, Kenji Uchino,

“Novel Method for Driving the Ultrasonic Motor”, ieee transactions on ultrasonics, ferroelectrics,

and frequency control, vol. 49, no. 10, pp 1356-1362,october 2002.

T. Takano, H. Hirata, and Y. Tomicawa, “Analysis of nonaxisymmetric vibration mode piezoelectric annular plate and its application to an ultrasonic motor,” IEEE Trans. Ultrason., Ferroelect. , Freq. Contr., vol. 37, no. 6, pp. 558–565, 1990.

R. P. Bishop, “Multi-layer piezoelectric transformer,” US Patent5,834,882, Nov. 10, 1998.

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Thank you