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:
Oct. 19, 1999
Filed:
Nov. 19, 1997
Applicant:
Inventor:
Philip Cooke, Nashua, NH (US);
Assignee:
Unitrode Corporation, Merrimack, NH (US);
Primary Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318799 ; 318807 ; 318811 ;
Abstract
A controller for variable speed three-phase AC squirrel-cage induction motors in accordance with a volts-per-hertz control method is disclosed. Direct current ('DC') link current is employed to compensate for rotor slip. In particular, rotor slip is estimated and added to a speed reference command to compensate for changing loads. A direction input and speed reference command provide complete control over the induction motor.