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In
this issue:
One-way repeating transmission Bi-directional AC-DC converter Links
within the Virginia
Tech Intellectual The
Bradley Department of Electrical and Computer Engineering
Center
for Power Electronics The Department of Aerospace and Ocean Engineering (540-231-6611) Faculty
Expertise Research
Division Interdisciplinary
Research Virginia
Tech News Virginia
Tech Intellectual In previous issues: 2002 January 2002 - Volume 10, Number 1: Method to establish genetic markers receives patent. Making it easy to program your VCR — from the Internet. Forests can restore surface mined land. February 2002 - Volume 10, Number 2: Project makes it easier for U.S. presidents to learn from history; faster, smaller microprocessor technology developed at Virginia Tech; tree named for VT chemistry professor March 2002 - Volume 10, Number 3: One-stop-shop to access hundreds of databases used for Social Services Administration; Communicating across 10 time zones; Longer shelf life for shredded cheese E Only. April 2002 - Volume 10, Number 4: Examples of software developed for collaboration, virtual environments, libraries, instruction, engineering in various applications, etc. E Only. May 2002 - Volume 10, Number 5: Fiber-optic field sensor immune to EMI, Mapping plant genomes, Machine vision, Smart Road June 2002 - Volume 10, Number 6: One-way repeating transmission, Bi-directional AC-DC converter, Flight control E Only July 2002 - Volume 10 Number 7: Is accounting chicanery SOP? Affordable, detachable power for wheelchairs. Improving food security E
Only August 2002 - Volume 10,
Number 8 - Better winegrapes, Protecting the Bay, Preservng farm
land |
Volume
10, Number 6 
June
2002
EDGE newsletters contain brief descriptions of research activities and discoveries at Virginia Polytechnic Institute and State University and provides links to researchers, centers, and sources of additional information.
2001
patents:
From buckeyballs to raspberries
Virginia Tech researchers received 15 patents and eight plant variety protections during 2001. The recipients were honored in May by the university and Virginia Tech Intellectual Properties Inc. (VTIP).
"It is a pleasure to recognize the individuals who have contributed to a successful 17-year technology transfer program," says Mike Martin, executive vice president of VTIP.
Discoveries include new materials, electronics, animal health, human health, and environmental health enhancements, and a wonderful new raspberry, as well as improved varieties of wheat and soybeans. Three examples appear in this issue.
One-way repeating transmission
View the entire list at: 2001patents.html
Do not return to sender
Ph.D. graduate Boris Davidson and electrical engineering professor Charles Bostian received patent 6,246,693 for "One-way Packet Communication Channel with Retransmissions." The patent is for a random access technique designed for any remote transmitter that sends messages infrequently but requires that such messages get through within seconds. Examples are wireless smoke alarms, burglar alarms, biohazard sensors, equipment status monitors, sales terminals, or any application where only one-way transmission is needed and remote equipment has to be cheap.
Bostian explains, "In most systems, a remote station will transmit until notified that the message has been received. This requires that the remote station have both a transmitter and a receiver. Our patent dispenses with the receiver and transmits the message in a way that offers a high probability that it will be received, saving the cost of a receiver."
Bi-directional AC-DC converter more efficient
Ph.D. graduate Kunrong Wang and electrical engineering professor Fred Lee, director of the Center for Power Electronic Systems (CPES), received patent 6,330,170 for a "Soft-Switched Quasi-Single-Stage Bi-directional Inverter/Charger" that converts AC power to DC power and vice versa. The research was sponsored by Heart Interface Corporation of Canada, manufacturer of DC-AC power inverter/charger systems for motorhomes and campers. They wanted to run 110V AC outlets in a camper from automotive-type DC batteries, then have the batteries recharge when the engine is running or the camper is plugged into an AC source.
The DC-AC task is usually performed in two steps, Lee explains. "The battery voltage has to be converted to a higher voltage level by a DC-DC converter, then the voltage has to be inverted to AC output."
The Virginia Tech invention provides a more efficient power conversion process using a single conversion step instead of two conversion steps, and can convert power in either direction. The invention developed at CPES by Wang and Lee also uses a soft-switching technique to reduce the loss incurred during switching, thus making it a more efficient circuit. The product is also less expensive to produce.
"It could also be used in homes, offices, and other locations where backup systems are needed in case of a power outage. Such an application is often referred to as uninterrupted power supplier (UPS)," says Lee.
Flight control improved
Wayne Durham of aerospace engineering received patent 6,278,908 for "Computationally Efficient Control Allocation." Military tactical aircraft must be able to maneuver rapidly under a range of conditions. These aircraft are equipped with redundant control surfaces. It is important to find the most effective combinations of these surfaces so that the aircraft is not carrying unnecessary weight and complex hydraulic systems. Optimal combinations must be calculated in real-time to adapt to any control system damage and failures while in flight.
Durham's patented method has been tested in Tech’s manned-flight simulator and demonstrates clear advantages over other control methods.