ULTRASONIC MOTOR DRIVE CIRCUIT AND METHOD

PROBLEM TO BE SOLVED: To obtain an ultrasonic motor drive circuit and method which can effectively prevent noise generated, particularly when an ultrasonic motor stops. SOLUTION: A microcomputer 32 sets a phase control signal, to provide a phase different of 90 deg. between a phase A drive signal ou...

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Bibliographic Details
Main Authors YOKOE HIFUMI, OTA TSUTOMU
Format Patent
LanguageEnglish
Published 12.07.2002
Edition7
Subjects
CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
GENERATION
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Summary:PROBLEM TO BE SOLVED: To obtain an ultrasonic motor drive circuit and method which can effectively prevent noise generated, particularly when an ultrasonic motor stops. SOLUTION: A microcomputer 32 sets a phase control signal, to provide a phase different of 90 deg. between a phase A drive signal outputted from a phase- A amplifying circuit 42 and a phase-B drive signal, outputted from a phase-B amplifying circuit 44 in order to generate the maximum torque, when the ultrasonic motor is driven under normal conditions. When the ultrasonic motor stops its operation, the value of the phase control signal is reduced gradually, thereby a phase difference between the phase-A drive signal and phase-B drive signal is gradually changed from 90 deg. to 0 deg. during the prescribed period.
Bibliography:Application Number: JP20000392882