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:
May. 30, 2000
Filed:
Jul. 31, 1998
David A Cross, Sandy Beds, GB;
Neal George Stewart, Tsuen Wan, HK;
Astec International Limited, Hong Kong, US;
Abstract
Effective harmonic correction without frequency, power or voltage limitations is achieved in a single-stage DC-to-DC converter by disconnecting the bulk capacitor of a typical single-stage converter during low voltage conditions, and by using various phase and cycle modulation techniques associated with a switchable auxiliary transformer winding which charges the bulk capacitor to control its voltage. A means is thus provided to control the level of harmonics generated depending upon the level of the AC output voltage. When the auxiliary winding is used as a clamp winding, full ZVS conditions are provided for both the auxiliary winding switch and the converter's primary winding switch. Energy can then also be directed, under independent control of the switched auxiliary winding, to independent power nodes, i.e., either the output capacitance and load, or the bulk capacitor. This ensures that the output voltage will not be affected during any period needed to recharge the bulk capacitor.