Electronic Engineering Final Year Project

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Electronic Engineering Final Year Project

• Progress Presentation

Title Electromagnetic shielding techniques for
inductive powering applications  Supervisor
Maeve Duffy 
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Topics of discussion

• Inductive Power Transfer
• Transmitter and receiver circuits
• Applications
• Electromagnetic Shielding
• Progress to Date
• Project Plan

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Inductive Power Transfer

• Inductive power transfer is the wireless transfer
  of electrical power from a source to an object
  requiring power.
• Inductive coupling involves the use of magnetic
  fields to stimulate the movement of current
  through a wire.
• Advantages No hazardous, inconvenient cables and
  wires.

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Transmitter and receiver coils

• To transfer power wirelessly we need transmitter
  and receiver coils.
• Transmitter coil is connected to power source
  which produces a magnetic field.
• For a current to be induced, must add a receiver
  coil inside the transmitter coils magnetic field.
• receiver coil must be close to the transmitter
  coil for inductance to occur.

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• 2 Applications
• Inductive charging platform
• Used for charging different
  mobile electronic devices, in which transmitter
  and receiver coils are close together.
• Implanted biomedical devices
• (transmitter and receiver coils far apart and
  therefore coupling levels are low)

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Applications

• Charging platform
• The charging platform contains inbuilt
  transmitter coils which induce a current in the
  receiver coils in the mobile devices when they
  are brought close to the platform.
• Transmitter and receiver coils must be close
  together as the magnetic fields they produce are
  relatively small.
• The bigger the magnetic field the less efficient
  it becomes.
• To Improve efficiency we can implement resonant
  circuits in both the transmitter and receiver
  circuits.

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Resonance circuit

• By adding resonance circuits that have the same
  resonance frequency the current can tunnel from
  the transmitter to the receiver coil.
• This improves the efficiency of energy transfer
  as energy is not scattered in all directions.

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Applications (cont.)

• Biomedical applications
• The transmitter and receiver coils in these
  devices are much further apart resulting in low
  inductive coupling levels.
• Inductive coupling is used to transfer pulses
  from the externally worn transmitter to the
  implanted receiver circuit.
• These pulses are applied to the relevant nerve
  endings

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Electromagnetic Shielding

• EM shielding is the process of limiting the flow
  of EM fields by using a barrier made of
  conductive material. In the charging platform,
  shielding is needed to avoid EM flux from
  escaping trough the bottom.
• I will be comparing the performance of different
  shielding layers. (dielectric copper, ferrite
  copper).
• This is done using Matlab and Ansoft.

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Progress to Date

• Research
• transmitter and receiver circuits.
• Inductive Power transfer applications
• Resonant circuits
• Electromagnetic shielding and the different
  electromagnetic shielding techniques.
• Software (Matlab, Ansoft)

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Progress to Date (cont.)

• Programming and simulation
• Matlab Programmed formula to find the mutual
  inductance between two planar windings.
• Ansoft used to simulate inductance.
• I got good agreement between the two for the
  value of mutual inductance.

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Progress to Date (cont.)

• Built demonstrator circuit which contains
  transmitter and receiver coils.
• Built a few different transmitter coils

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Project Plan

• Build demonstrator circuit which will show
  inductive power transfer by lighting an LED.
• Continue to investigate the effect of different
  shielding techniques using analytic and FEA
  models
• Investigate the performance of different magnetic
  materials in shielding
• Develop analytic models for predicting magnetic
  field levels and transmitter coil inductance for
  different shield structures
• Investigate health and safety issues.

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Questions ???