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. 04, 2011
Filed:
Mar. 11, 2009
Daniel Kling, Västerås, SE;
Gunnar Johansson, Skultuna, SE;
Daniel Kling, Västerås, SE;
Gunnar Johansson, Skultuna, SE;
ABB AB, , SE;
Abstract
A method for reducing the influence of a DC component in a load current of an asynchronous three-phase motor, in which the voltages of two of the three phases are controlled by adjusting firing angles of semiconductor devices of the type turning-off at zero-crossing of the current therethrough comprises the steps carried out for each said controlled phase: detecting turn-off times of the semiconductor devices, calculating a value of a change of firing angle of the semiconductor devices needed for changing the length of the time period between two subsequent turn-off times for compensating for the influence of a DC component, and determining the firing angle of said semiconductor devices in dependence of the result of this calculation.