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ECE 291 Senior Design Electric Boat Team

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ECE 291 Senior Design Electric Boat Team Powered By Docstoc
					ECE 291 Senior Design
Electric Boat Team
Introduction
   This is a research project in
    collaboration with Electric Boat
Team Members
 Amy Henne
 Jason Holland
 Ricardo Silva
 Mark Wojenski
Objective
 Wireless Power Transmission
 Wireless Data Transfer System
Wireless Power Transmission (WPT)

   Researched Several Methods of WPT
    – Optical Box
    – RF Box
    – Waveguide
Optical Box
 Light source
 Solar cells on
  individual
  sensor
  modules
 Highly polished
  internal
  surfaces of box
Optical Box: Problems
 Solar cell efficiency = 18%
 Light source efficiency = 65%
  (fluorescent)
 Combined total efficiency = 11.7%
 4 receivers * 2 Watts / 11.7% =
  68.37Watts
RF Injection into Square Box
 RF injected into
  the middle of the
  box
 Each sensor
  module would
  convert RF to
  DC.
RF Box: Problems
 Reflected energy
 Uncontrollable
  dispersion of RF
  energy
 VSWR might
  damage
  transmitter
Waveguide
 Control of
  propagating modes
 TE10 mode dominant
 Easy to calculate
  where power
  concentrations are
  greatest
Waveguide: Final Choice for WPT

   Waveguide System
    – RF Generator
    – WG Dimensions
    – RF to DC
      Conversion
RF Generator
 Supplies the energy used for our
  WPT
 Operating frequency of the RF
  generator < frequency of data
  transmission
 Chose Operating Frequency of 1000
  MHz
RF Generator
   Voltage Controlled Oscillator (VCO)
    is a ZOS-1025
    – puts out up to 8.0 dBm (6.3mW)
   RF amplifier is a LZY-2 (40 dB gain)
    – rated to 20 watts
Waveguide Dimensions
   Based on Frequency of
    Transmission
    – Waveguide with parameter
      a slightly greater than 5.9
      inches and parameter b
      equal to 0.5*a= 2.95 inches
      can properly transmit our
      RF data
    – A waveguide of 7.87” x
      3.93” x 5’was built by
      Electric Boat out of
      aluminum for our
      prototype
Waveguide Features
 Use of ARC-UD-11091
  RAM material to
  reduce standing
  waves within
  waveguide
 Separate data
  reception circuitry
  compartment
RF to DC Conversion - I
 A Rectenna, or
  rectifying antenna is a
  receiving antenna
  combined with a
  rectifying circuit, which
  converts RF into the
  desired DC power
 Must be efficient in the
  RF to DC Conversion
RF to DC Conversion - II
 Low pass filter consists of one 10pF
  capacitor to filter out the ripple
 1N5711 Schottky diode
    – High power (250 mW)
    – Reverse voltage breakdown at about 70V
Wireless Data Transmission
 Wirelessly transfers audio data
 Data must be modulated and
  transmitted back to the receiver
 Explored Several Different
  Transmission Frequencies
    – 440 MHz Transmission
    – 900 MHz Transmission
    – 2.45 GHz Transmission
440 MHz Data Transmission
 First idea was to use circuitry from inside
  of a toy walkie-talkie to transmit our audio
  data
 This was dropped because the operating
  frequency was around 440 MHz and this
  did not fit with our design requirement of
  the WPT Transmission Frequency < Data
  Transmission Frequency
900 MHz Data Transmission
 Many commercially available devices
  in this frequency range
 Discarded because RF operating
  frequency of 1000 MHz is very close
  to 900 MHz
    – May cause interference between the
      power and data transmission
2.45 GHz Data Transmission
   Commercially available devices
    including:
    – Home telephones
    – Wireless audio/video transmitters
    – Wireless home PC networking devices
   Approximately 1.5 GHz higher that
    WPT
    – Allows better separation of signals
Modulation Schemes for Data
 Originally decided to design our own
  modulation circuitry
 Modulation Schemes considered:
    – AM and FM
    – Spread Spectrum
    – Bluetooth Standard
Frequency and Amplitude Modulation

 FM and AM are modulation techniques
  used in commercial radio
 Simple to implement
 Lacks any built in resistance to electrical
  interference
    – Does not ensure there is no interference
      between Data and Power Signals
   Shortage of available frequencies if
    expanded for many sensors
Spread Spectrum
   Transmitted information is spread out
    over a range of frequencies
    – improves both transmitter and receiver’s
      immunity to interference
 Information is divided into small pieces
  and each piece is transmitted at a different
  frequency in the predetermined range
  around 2.45 GHz
 Only a spread spectrum receiver that is
  tuned to sync with the transmitter will be
  able to receive and decode the transmitted
  information
Bluetooth Standard
   Characteristics of Bluetooth
    compatible devices include:
    – operation in the 2.45 GHz range
    – frequency hopping spread spectrum
      transmission
    – low power consumption
Bluetooth Standard
   Factors in not Choosing Bluetooth
    – Three development kits priced at $2500
      a piece would be needed to implement
      our project
    – Scheduled to go on the Market in
      Summer 2002
2.4 GHz Cordless Phones
 Commercially available
 Inexpensive
 Didn’t need to design our own modulation
  and data transmission circuitry
 Experimented with two phones:
    – Siemens Gigaset 4015
    – Motorola MA350
Siemens vs. Motorola
   Originally thought Siemens would be the
    optimal choice because it consumed less
    power during operation
    – Average Power Consumption of 180 mW
    – Current spike of up to 600 mA at turn on
   Motorola was ultimately chosen
    – Average Power Consumption of 265 mW
    – No current spike at turn on
Final Design
 Waveguide for WPT
 RF Generator
 RF to DC Conversion
 2.4 GHz Motorola
  Phones for Wireless
  Data Transmission
    – Allows multiple
      signals to be sent
      simultaneously
Final Design
 Antenna from the
  handset of the phone
  is positioned so that it
  enters the waveguide
 Phone’s antenna will
  transmit to the base
  stations that are
  placed in the second
  compartment of the
  waveguide
RF Distribution and Data Transmission
                                      Sensor
                                      (Microphone)


                                      Pre-Amp,
      1000 MHz VCO                    Modulator


                                          2.4GHz
                          DC to           Transmitter
     Power Amp                                             Speake
                          Sensor
                                                           r

                      Rectifier, Filter
                      Volt.Regulator                    2.4GHz
                                                        Receiver




    1000 MHz ¼ wave
    Monopole Ant.
Voltage Regulator Circuitry for Phone Box
Circuitry for Phone Box
Adjustable 1-14VDC Power Supply with Vtrip
               for VCO Power
Adjustable 1-16VDC Power Supply with Vtrip
             for VCO Frequency
UCONN Budget and Expenses
   WPT
    – $610.00
   Data Transmission
    – $400.00
   Miscellaneous
    – $400.00
 Current Budget $1410.00
 Other parts supplied by EB
Project Phases and Timeline
  References
1. Microelectronic / Optoelectronic Devices,
   Supplementary Notes, Part 1, F.C. Jain, UCONN, Spring
   2002.
2. http://acre.murdoch.edu.au/refiles/pv/text.html, website
   with information on solar cells.
3.http://www.kurasc.kyoto-u.ac.jp/plasma-group/sps/milax-
   e.html , website with information on RF to DC
   conversions.
4.http://www.fnrf.science.cmu.ac.th/theory/waveguide/Wave
   guide%20theory%206.html , website with information on
   waveguides
5. http://www.cwc.nus.edu/~sg/~cwcpub/zfiles/ap98.pdf ,
   website with information on rectennas.
Acknowledgements
 Professor Rajeev Bansal,
  University of Connecticut
 Mr. Michael Sullivan, Electric
  Boat
 Angel Rodriguez
Questions?

				
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