Absolute value calculating element for converting AC signals into DC signals

• US 6,937,034 B1
• Filed: 10/11/2000
• Issued: 08/30/2005
• Est. Priority Date: 11/12/1999
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Takeuchi, Yukihisa, Ohwada, Iwao
• Primary Examiner(s): Nguyen, Vinh P.
• Application Number:
  US09/688,039
• Time in Patent Office: 1,784 Days
• Field of Search: 324/437, 324/244, 324/727, 428/461, 310/323, 310/328, 310/3.4, 310/316.61, 310318-319, 310/323.06, 310/311, 310/367, 327100-103, 327/354
• US Class Current: 324/727
• CPC Class Codes: G01R 19/22 using conversion of ac into dc
• CPC Class Codes: H02M 7/53876 based on synthesising a desired voltage vector via the selection of appropriate fundamental voltage vectors, and corresponding dwelling times

Abstract

A sensor element formed of PZT is overlapped onto an actuator formed of electrostrictive elements, and both members are pinched between a rigid body that is not deformed. By impressing an alternating-current signal to the actuator, the sensor element is deformed in accordance with the amount of deformation thereof to use the thus generated electromotive force of the sensor element as a signal for the absolute value calculation.

Claims

1. An absolute value calculating element comprising:

electrostrictive elements; and

detecting means for detecting an amount of deformation of said electrostrictive elements;

wherein an alternating-current signal is calculated into an absolute value and output by impressing the alternating-current signal to said electrostrictive elements to deform said electrostrictive elements and by converting a distortion of said electrostrictive elements into a direct-current electric signal using said detecting means.

2. The absolute value calculating element of claim 1, wherein said detecting means comprises a piezoelectric/electrostrictive element that is deformed in proportion to the amount of said deformation of said electrostrictive elements;

and

wherein the alternating-current signal is calculated into an absolute value and output by impressing the alternating-current signal to said electrostrictive elements to deform said electrostrictive elements and by outputting an electromotive force generated by said deformation of said piezoelectric/electrostrictive element.

3. The absolute value calculating element of claim 2, wherein said electrostrictive elements and said piezoelectric/electrostrictive element are overlapped and pinched between a rigid body that is not deformed.

4. The absolute value calculating element of claim 2, wherein one end of each said electrostrictive element is fixed in a deforming direction thereof while the other end of each said electrostrictive element is fixedly attached to one surface of an elastic plate body, said elastic plate body having one fixed end and another free end;

and

wherein said piezoelectric/electrostrictive element is plate-shaped and fixedly attached to an opposed surface of said elastic plate body.

5. The absolute value calculating element of claim 4, wherein said electrostrictive elements are plate shaped.