The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 01, 2008
Filed:
Nov. 25, 2002
Gerhard Diefenbach, Aachen, DE;
Christian Reichinger, Neutraubling, DE;
Hans Steinbusch, Landgraaf, NL;
Matthias Wendt, Wuerselen, DE;
Gerhard Diefenbach, Aachen, DE;
Christian Reichinger, Neutraubling, DE;
Hans Steinbusch, Landgraaf, NL;
Matthias Wendt, Wuerselen, DE;
Koninklijke Philips Electronics, N.V., Eindhoven, NL;
Abstract
A piezoelectric driving device and a regulation method for a piezoelectric driving device are proposed. Piezoelectric driving devices known so far show a characteristic with which the electric power applied to the motor drops when the load increases. This behavior, which leads to a strong reduction of the range of use of such motors, is counteracted by predefining the amplitude of the excitation voltage so that the effective power does not drop with increasing load. For this purpose the electrical effective power is determined from the excitation voltage and the current flowing through the piezoelectric resonator. Alternatively, with a predefined fixed phase angle between excitation voltage and current a regulation may also be effected in the way that the current is kept to the constant value. A further aspect of the invention relates to a unit for limiting the current flowing through the piezoelectric resonator, so as to avoid this component being damaged.