Electronic Engineering Final Year Project Progress Presentation Title: Electromagnetic shielding techniques for inductive powering applications Supervisor : Maeve Duffy

Topics of discussion  Inductive Power Transfer  Transmitter and receiver circuits  Applications  Electromagnetic Shielding  Progress to Date  Project Plan

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.

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.

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

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.

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.

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

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.

Progress to Date  Research: transmitter and receiver circuits. transmitter and receiver circuits. Inductive Power transfer applications Inductive Power transfer applications Resonant circuits Resonant circuits Electromagnetic shielding and the different electromagnetic shielding techniques. Electromagnetic shielding and the different electromagnetic shielding techniques. Software (Matlab, Ansoft) Software (Matlab, Ansoft)

Progress to Date (cont.)  Programming and simulation Matlab: Programmed formula to find the mutual inductance between two planar windings. Matlab: Programmed formula to find the mutual inductance between two planar windings. Ansoft: used to simulate inductance. Ansoft: used to simulate inductance. I got good agreement between the two for the value of mutual inductance. I got good agreement between the two for the value of mutual inductance.

Progress to Date (cont.)  Built demonstrator circuit which contains transmitter and receiver coils.  Built a few different transmitter coils

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.

Questions ???