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:
Sep. 14, 1993
Filed:
Oct. 24, 1991
Gary L Galloway, Rockford, IL (US);
Thomas S Latos, Huntley, IL (US);
Derrick Roe, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
The problem of minimizing DC content in a dual converter system (18) is addressed with dual inverters (36,38) having outputs connected in parallel through an interphase transformer (42). In order to minimize DC current flow through the transformer (42) caused by non-ideal switching characteristics, a current transducer (44) senses primary current out of each inverter (36,38). Particularly, the current transducer (44) comprises a current transformer which senses the currents differentially. This sensing removes load current so that the sensed current represents interphase transformer excitation current and DC current. The excitation current is eliminated by filtering and averaging resulting in a DC signal proportional to DC current through the interphase transformer (42), which is transferred to a control processor (40) which modifies PWM patterns sent to the inverters (36,38) to reduce the DC current.