Electronic Engineering Electronic Engineering Final Year ProjectFinal Year Project

Progress PresentationProgress Presentation

Title: Electromagnetic shielding techniques for inductive powering applications  Supervisor : Maeve Duffy 

Topics of discussionTopics of discussion

Inductive Power TransferInductive Power Transfer Transmitter and receiver circuitsTransmitter and receiver circuits ApplicationsApplications Electromagnetic ShieldingElectromagnetic Shielding Progress to DateProgress to Date Project PlanProject Plan

Inductive Power TransferInductive Power Transfer

Inductive power transfer is the wireless Inductive power transfer is the wireless transfer of electrical power from a source transfer of electrical power from a source to an object requiring power. to an object requiring power.

Inductive coupling involves the use of Inductive coupling involves the use of magnetic fields to stimulate the movement magnetic fields to stimulate the movement of current through a wire.of current through a wire.

Advantages: No hazardous, inconvenient Advantages: No hazardous, inconvenient cables and wires.cables and wires.

Transmitter and receiver coilsTransmitter and receiver coils To transfer power wirelessly we need To transfer power wirelessly we need

transmitter and receiver coils.transmitter and receiver coils. Transmitter coil is connected to power source Transmitter coil is connected to power source

which produces a magnetic field.which produces a magnetic field. For a current to be induced, must add a receiver For a current to be induced, must add a receiver

coil inside the transmitter coils magnetic field.coil inside the transmitter coils magnetic field. receiver coil must be close to the transmitter coil receiver coil must be close to the transmitter coil

for inductance to occur.for inductance to occur.

2 Applications:2 Applications:

Inductive charging platform:Inductive charging platform:

Used for charging different Used for charging different mobile electronic devices, in which mobile electronic devices, in which transmitter and receiver coils are close transmitter and receiver coils are close together.together.

Implanted biomedical devicesImplanted biomedical devices::

(transmitter and receiver coils far apart (transmitter and receiver coils far apart and therefore coupling levels are low)and therefore coupling levels are low)

ApplicationsApplications Charging platform:Charging platform: The charging platform contains inbuilt transmitter The charging platform contains inbuilt transmitter

coils which induce a current in the receiver coils in coils which induce a current in the receiver coils in the mobile devices when they are brought close to the mobile devices when they are brought close to the platform.the platform.

Transmitter and receiver coils must be close Transmitter and receiver coils must be close together as the magnetic fields they produce are together as the magnetic fields they produce are relatively small. relatively small.

The bigger the magnetic field the less efficient it The bigger the magnetic field the less efficient it becomes.becomes.

To Improve efficiency we can implement resonant To Improve efficiency we can implement resonant circuits in both the transmitter and receiver circuits.circuits in both the transmitter and receiver circuits.

Resonance circuitResonance circuit

By adding resonance circuits that have the By adding resonance circuits that have the same resonance frequency the current same resonance frequency the current can tunnel from the transmitter to the can tunnel from the transmitter to the receiver coil.receiver coil.

This improves the efficiency of energy This improves the efficiency of energy transfer as energy is not scattered in all transfer as energy is not scattered in all directions.directions.

Applications (cont.)Applications (cont.)

Biomedical applications:Biomedical applications: The transmitter and receiver coils in these The transmitter and receiver coils in these

devices are much further apart resulting in devices are much further apart resulting in low inductive coupling levels.low inductive coupling levels.

Inductive coupling is used to transfer Inductive coupling is used to transfer pulses from the externally worn transmitter pulses from the externally worn transmitter to the implanted receiver circuit.to the implanted receiver circuit.

These pulses are applied to the relevant These pulses are applied to the relevant nerve endingsnerve endings

Electromagnetic ShieldingElectromagnetic Shielding

EM shielding is the process of limiting the EM shielding is the process of limiting the flow of EM fields by using a barrier made flow of EM fields by using a barrier made of conductive material. In the charging of conductive material. In the charging platform, shielding is needed to avoid EM platform, shielding is needed to avoid EM flux from escaping trough the bottom.flux from escaping trough the bottom.

I will be comparing the performance of I will be comparing the performance of different shielding layers. (dielectric + different shielding layers. (dielectric + copper, ferrite + copper).copper, ferrite + copper).

This is done using Matlab and Ansoft.This is done using Matlab and Ansoft.

Progress to DateProgress to Date

Research:Research: transmitter and receiver circuits.transmitter and receiver circuits. Inductive Power transfer applicationsInductive Power transfer applications Resonant circuitsResonant circuits Electromagnetic shielding and the different Electromagnetic shielding and the different

electromagnetic shielding techniques.electromagnetic shielding techniques. Software (Matlab, Ansoft)Software (Matlab, Ansoft)

Progress to Date (cont.)Progress to Date (cont.)

Programming and simulationProgramming and simulation Matlab: Programmed formula to find the Matlab: Programmed formula to find the

mutual inductance between two planar mutual inductance between two planar windings. windings.

Ansoft: used to simulate inductance.Ansoft: used to simulate inductance. I got good agreement between the two for the I got good agreement between the two for the

value of mutual inductance.value of mutual inductance.

Progress to Date (cont.)Progress to Date (cont.) Built demonstrator circuit which contains Built demonstrator circuit which contains

transmitter and receiver coils.transmitter and receiver coils.

Built a few different transmitter coilsBuilt a few different transmitter coils

Project Plan:Project Plan: Build demonstrator circuit which will show Build demonstrator circuit which will show

inductive power transfer by lighting an LED.inductive power transfer by lighting an LED. Continue to investigate the effect of different Continue to investigate the effect of different

shielding techniques using analytic and FEA shielding techniques using analytic and FEA modelsmodels

Investigate the performance of different Investigate the performance of different magnetic materials in shieldingmagnetic materials in shielding

Develop analytic models for predicting magnetic Develop analytic models for predicting magnetic field levels and transmitter coil inductance for field levels and transmitter coil inductance for different shield structures different shield structures

Investigate health and safety issues. Investigate health and safety issues.

Questions ???Questions ???