Virtual Corporation Students Build First-of-its-Kind Propulsion System
This past spring, a Virginia Tech student virtual corporation team developed the world's first electric propulsion system using a switched-reluctance actuator.
The effort was Phase I of a multi-year program to develop a prototype of a maglev personal rapid transit system. The switched reluctance system is expected to be less expensive than other propulsion systems, and therefore has a high potential for future implementation.
Tech's microprocessor-controlled system propels a model car down a 20-foot-long track at a speed of five feet per second, with .5 millisecond position accuracy. The linear switched reluctance stator and translator propulsion system is composed of nearly one thousand steel laminations. Its steel guideway is manufactured to 1-millimeter accuracy, and its wireless vehicle-to-ground communication system uses a patented fiber optic system to sense the position of the vehicle.
Coils Are Key
The key to the system is the unique method of construction made possible by using switched reluctance technology. The coils wound around the stators that provide the magnetic flux are independent, unlike in other propulsion systems where the coils operate in tandem.
"Because of the simple nature of the single coils, reliability is increased and manufacturing costs are estimated to be 30 percent less than with other systems," explained Krishnan Ramu who serves as chief faculty advisor to the program. "The switched reluctance system is not dependent on a single coil," he continued. "If a coil fails, the system can still operate. This provides a significant increase in reliability." Maintenance costs are also reduced because coils can be replaced singly, instead of having to replace entire sections of tandem coils, he said.
The development effort is part of Tech's Virtual Corporation program, a novel concept in which student-run corporations design real products, systems, and technology based on actual market conditions.
The virtual corporation represents as closely as possible the social context, personnel positions, departmental functions, and structure of commercial engineering corporations.
The team developing the rapid transit prototype is commonly referred to as PERTS (Personal Rapid Transit Systems). Phase II of the prototype effort involves incorporating a magnetic levitation system in the testbed.
The Bradley Department of
Electrical and Computer Engineering