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Virginia Tech Researchers Receive Energy Patents

March 01, 2006 by Jeff Shepard

Virginia Tech faculty members, staff, and students received 17 patents during 2005. Inventions include seven technologies that use energy more efficiently and safeguard the electric grid and oil resources -- including two that received R&D 100 awards.

"We know these patents will enhance Virginia Tech's reputation as a place that contributes to the creation of new knowledge and entrepreneurship, and provide recognition of Virginia Tech's significant role in economic development," said Mark Coburn, the new executive vice president of Virginia Tech Intellectual Properties (VTIP). "University patents also benefit scholarship by setting the stage for new innovations to follow."

The Center for Power Electronic Systems (CPES) received five patents. Fred C. Lee, director of CPES, electrical and computer engineering faculty member Jih-Sheng Lai, and former visiting scientist Lizhi Zhu, now with Ballard Power Systems, invented Accelerated Commutation for Passive Clamp Isolated Boost Converters (6,876,556). The invention is an efficient and cost effective bidirectional dc-dc converter that reduces switch voltage stress. For example, it allows smooth conversion between two sources of dc generating devices, such as between fuel cells and high voltage batteries, to provide appropriate current levels for driving an electric vehicle and for the electrical components on the vehicle, such as lights and sensors, regardless of voltage. The technology has been adopted by Ballard Power Systems, the largest fuel-cell company in the world.

Lee, research assistant professor Ming Xu, and Ph.D. graduate Jinghai Zhou received patents for a Multi-phase Interleaving Isolated dc-dc Converter (6,944,033), designed to provide more power, higher operating frequency, and much reduced switching losses to power the next generation of microprocessors, as well as other portable telecommunication and portable equipment; and a Bridge-Buck Converter with Self-Driven Synchronous Rectifiers (6,859,372), which provides a more power-efficient and low-cost solution for controlling the high-frequency voltage/current rectifier (synchronous rectifier) commonly used in low-voltage, high-current dc-dc converters, such as are in desktop and laptop computers, servers, and power supplies for telecommunication devices.

Other inventions from CPES that received patents are an Emitter Turn-Off Thyristors (ETO) (6,933,541), invented by Alex Huang, formerly with CPES and now a professor at North Carolina State University; and a Solid State DC Circuit Breaker (6,952,335), invented by Huang and electrical engineering Ph.D. graduates Xigen Zhou and Zhenxue Xu. The circuit breaker is a high-speed, solid-state circuit breaker capable of interrupting high dc currents without generating an arc. It uses the ETO thyristor as the switch. The American Competitiveness Institute helped develop a manufacturing process for the ETO and Solitronics licensed the product from VTIP.