Image Credits and References:
The picture on the left is from “Goodbye Wires!” by Franklin Hadley, MIT News, June 7, 2007 http://web.mit.edu/newsoffice/2007/wireless-0607.html
The picture on the right is from Dries van Wageningen and Eberhard Waffenschmidt, “Inductive Power Transmission and Transfer Efficiency,” Wireless Power Consortium, Philips Research http://www.wirelesspowerconsortium.com/technology/transfer-efficiency.html
The task is to design and build a pair of self-resonant coils that transmits power to a 60-watt light bulb over a distance of several meters, as demonstrated by the MIT wireless power team shown in the picture above. The transmitting coil will be powered from a 120-watt Colpitts oscillator with an operating frequency near 10 MHz. The receiving coil and light bulb are built to match the resonant conditions of the transmitting coil. Experiments will be conducted to find the system’s efficiency and useful operating range. Diagnostic devices will be built to map the transmitting field and that map will be compared with simulations.
Level of Difficulty: Medium
resonant frequency, coupling coefficient, quality factor, system efficiency, Colpitts oscillator, skin effect
“Tesla and Wireless Energy: The power that could have been,” By Michael Jaeger, The Washington Times, December 31, 2014 http://www.washingtontimes.com/news/2014/dec/31/tesla-and-wireless-energy-power-could-have-been/
“Two Inductively Coupled RLC Circuits,” Author Unknown, Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer-Sheva, ISRAEL http://www.ee.bgu.ac.il/~intrlab/lab_number_7/Two%20inductively%20coupled%20RLC%20circuits.pdf
Electrical Engineer (2) – The Electrical Engineers on the project will design and build the 120-watt oscillator to power the transmitting coil. The assembly will include RF enclosures for safety and to limit electromagnetic interference (EMI) with adjacent equipment. Diagnostic devices will be installed to determine the oscillator is operating correctly without overheating. Overall oscillator efficiency will be determined as part of an overall system evaluation.
Mechanical Engineer (2) – Mechanical Engineers on the project will design and build the transmitting and receiving coils. Since the coils are self-resonant, their support structure must be nonconductive and not significantly contribute to the turn-to-turn tuning capacitance. Low-capacitance spacer devices will be designed and installed to set the coil’s resonant frequency and keep it stable against vibration and temperature changes.
Physicist (2) – Physicists on the project will design and build field-sampling loops that will measure and map the time-varying magnetic fields from the transmitting and receiving coils in space. The data map will determine a safe distance for people to be near the apparatus during operation, according to guidelines established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Field mapping results will be compared with simulations.
Computer Scientist (2) – Computer Scientists on the project will work closely with the Engineers and Physicists to collect and visualize diagnostic data from the oscillator and field-sampling coils using LabVIEW. The Computer Scientists will design and conduct a coupled coil experiment to determine the power transmission efficiency between the transmitting and receiving coils.
Designer (2) – The Designers will work closely with the Engineers to manufacture an experiment that can be easily transported, assembled quickly with few tools, and demonstrated to a crowd of people in a safe manner. In particular, the delicate coils must be transported carefully and suspended from non-conducting stands for demonstration.
Journalist (1) – The Journalist documents the project’s progress on the website, communicates with the local media, and is responsible for a final report to the principal sponsors and Power Mountain Engineering. The Journalist also works closely with the Multimedia Artist to provide video and graphic art displays for demonstrations that explain the project to the public. The whole project is your project.
Multimedia Artist (1) – The Artist also documents the project’s progress on the website and works with the Journalist to maintain the project’s presence on social media. Additionally, the Artist designs and organizes all public relations events to assure spectator safety and to enhance the community’s awareness of science and technology. The whole project is your project.
Business Manager (1) – The Business Manager is responsible for reporting the project’s progress against a predetermined schedule, determines critical path items to completion, and tracks project spending to assure that costs remain within a fixed budget. The Manager works with all team members to identify problems early and resolve them quickly. The whole project is your project.