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:
Nov. 28, 2000
Filed:
Mar. 23, 1999
William Anders Peterson, Vestal, NY (US);
Michael Francis Thompson, Columbia, MD (US);
Lockheed Martin Corporation, Johnson City, NY (US);
Abstract
A polyphase AC-to-AC inverter (300) for driving a polyphase load (50), which may be an unbalanced load, includes a wye-connected AC voltage source (12) having a neutral terminal (312). The source (12) is coupled to a rectifying arrangement (16) for producing direct voltage across a direct-voltage bus (22). A capacitive bridge (24) on the DC bus (22) has a tap (26) connected to the neutral (312) of the source. The capacitive bridge is isolated from the AC source harmonics by a zero sequence inductor (20). The DC bus voltage at the capacitive bridge feeds a polyphase switching bridge (40). The average voltage at the output of the switching bridge is recovered by a low-pass filter (30) connected to the load. The unbalanced load current is conducted through an inductor to the capacitive bridge tap and the source neutral, with the inductor impedance isolating the load neutral from the DC bus. The switching bridge control can introduce triplen harmonics in the output to increase line-to-line output voltage.