CPES-VT Researchers Awarded 7th U.S. Patent in 2007
U.S. Patent 7,254,047, entitled "Power Converters Having Output Capacitor Resonant with Autotransformer Leakage Inductance," was issued on August 7, 2007. This is the 7th U.S. patent of the year to be awarded to CPES-VT researchers.
Power Converters Having Output Capacitor Resonant with Autotransformer Leakage Inductance (VTIP #04.090)
- By Yuancheng Ren, Julu Sun, Ming Xu, Fred C. Lee
- US Patent: 7,254,047 (Issued: August 7, 2007)
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| Prototype converter using the patented technology, top- and bottom-view. |
Abstract: Power converters having reduced body diode conduction loss, reduced reverse recovery loss and lower switching noise, among other benefits, have a resonant capacitor Cr connected across an unfiltered output. The resonant capacitor Cr resonates with the leakage inductance Lk of the transformer. The resonant capacitor and leakage inductance are selected such that 1/2 a LC resonance period is equal to an ON time of each secondary switch S1 S2. The resonance provides zero current switching for secondary switches S1 S2, eliminates zero body diode conduction during dead times, and eliminates reverse recovery losses in the secondary switches. The present invention is applicable to many different circuit topologies such as full bridge, active clamp forward, push-pull forward, and center-tap secondary. The present converters provide high energy conversion efficiency and high frequency operation.
Since the implementation of IPPF (Intellectual Property Protection Fund) in 2002 at CPES-Virginia Tech, patenting activities have been on the rise, as IPPF has drastically streamlined the IP protection and access process for Principal-level members. Since 2006, Principal Plus members have been offered automatic IPPF at no additional cost, while Principal Members have the option to participate at the cost of $5,000 per year. On a quarterly basis, IPPF members meet with CPES inventors via telecon to evaluate invention disclosures produced under the Center's core and focused research efforts. They jointly decide which technologies to protect, with patenting costs covered by IPPF. Once a technology is protected, IPPF members are given non-exclusive, royalty-free right to use the technology, with two-year exclusivity.
For more info about CPES or the IPPF program, please contact CPES Industry Liaison, Teresa Shaw.