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:
Feb. 16, 2010
Filed:
Sep. 14, 2005
Applicants:
Ian Campbell Mcgill, Auckland, NZ;
Zhuang Tian, Auckland, NZ;
Inventors:
Ian Campbell McGill, Auckland, NZ;
Zhuang Tian, Auckland, NZ;
Assignee:
Fisher & Paykel Appliances Limited, Auckland, NZ;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02K 11/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A sensorless method and apparatus for detecting piston collisions in a free piston linear compressor motor. The waveform of the back EMF induced in the motor stator windings is analysed for slope discontinuities and other aberrations in a time window centred on the back EMF zero-crossings. Waveform slope artefacts are indicative of piston collisions and cause the motor power to be decremented in response.