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. 01, 1991
Filed:
Nov. 28, 1989
Applicant:
Inventors:
Nobuyoshi Mutoh, Katsuta, JP;
Keijiro Sakai, Hitachiota, JP;
Hiroshi Fujii, Chiba, JP;
Kenji Nantoh, Matsudo, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318811 ; 318803 ; 318798 ;
Abstract
In spatial vector control of a pulse width modulation (PWM) inverter adapted for variable speed drive of an induction motor, a difference vector between magnetic flux vectors occurring during adjacent sampling periods is generated by synthesizing a zero vector and voltage vectors in such a manner that a resultant voltage vector always includes as a component a minimum unit of a zero vector or a voltage vector, whereby even when the angular speed of rotation of the magnetic flux changes, the switching frequency of the PWM inverter is prevented from decreasing and the current ripple is reduced.