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:
Jul. 29, 2003
Filed:
Aug. 28, 2001
Markku Niemelä, Lappeenranta, FI;
ABB Oy, Helsinki, FI;
Abstract
A method of correcting the stator flux estimate midpoint in alternating-current systems, the method comprising the step of determining a stator flux estimate (&PSgr;s, est?). The method is characterized in steps of forming the sum of the squares of the rectangular components (&PSgr;sx, est?, &PSgr;sy, est?) of the stator flux estimate to obtain a reference variable (k), low-pass filtering the reference variable (k) in order to obtain a low-frequency component (k ) of reference variable, subtracting the low-frequency component (k ) from the reference variable (k) in order to obtain a difference variable (e), determining rectangular correction term components (&PSgr;sx, corr?, &PSgr;sy, corr?) of the stator flux estimate (&PSgr;s, est?) by multiplying the difference variable (e) by the rectangular components (&PSgr;sx, est?, &PSgr;sy, est?) of the stator flux and a correction coefficient (K ), and forming a midpoint-corrected stator flux estimate (&PSgr;s, fin?) by adding the correction term components to the components of the stator flux estimate.