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Life’s Ultimate Problem…. Solved By…. Preliminary Design Review. Ahmad Alawadhi Eric Willuweit Kegan Grimes Kyle Chessman Sean Flodberg. Team Iron Chefs. Overview. Project Objective Background Approach Sub-system Implementation Member Roles Schedule Contingency Plan. Chessman. - PowerPoint PPT Presentation
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Life’s Ultimate Problem…
Solved By…
Preliminary Design Review
Team Iron Chefs
Ahmad AlawadhiEric WilluweitKegan GrimesKyle ChessmanSean Flodberg
OverviewProject ObjectiveBackgroundApproachSub-system ImplementationMember RolesScheduleContingency Plan
Chessman
Project Objective The goal of our project is to innovate the
existing induction cooktop design with designated cooking locations and creating a “zone free” cooking range.
Chessman
Existing Cooktops Cook tops use one large copper coil for each
designated zone. The copper coils create a magnetic field which
induces eddy currents into the cookware above it.
These small currents heat the cookware through resistance of the material.
Chessman
Background Cookware used must be
a ferromagnetic material as the heat produced arises from Eddy Currents and the resistance caused by the skin layer of the metal.
Cookware must be flat-bottomed to maintain efficiency.
Universal Symbol for induction cooking
Chessman
Approach Utilize smaller copper coils in place of the large
single coils. Sense cookware’s location on the “zone-free”
range. Supply power to the coils that sense the
cookware.
Chessman
Inputs and Outputs
Alawadhi
System Flow Diagram
Alawadhi
Sub-system Implementation Systems
Indicator LEDs Copper coils Sensors
Alawadhi
Indicator LED Sub-system LEDs indicate which coils are being supplied
with power. LEDs on temperature knobs lit with same color
LED as the powered coils to display which coils the knobs correspond to.
Willuweit
Copper Coils Sub-system Power supplied through the IGBTs
PWM signal generated from the MCU Current transformer to feedback circuit
To optimize power transfer
Willuweit
Coil Construction 3 inch flat copper coils “Litz” copper wire
Small gauge insulated copper wire wound like a rope into a larger gauge wire for transporting high frequency currents
Take advantage of the “skin effect” used by transmission lines
Willuweit
Sensor Sub-system Sensors change resistance when cookware is
placed above them, causing a change in voltage.
High gain amplifier boosts the small signal to be noticed by the microcontroller.
Willuweit
Testing Potential Sensors Photodiodes Induction sensing Infrared LEDs Pressure sensing /
Mapping
Willuweit
MCU - Microcontroller Output at least seven PWM signals for our
desired hexagon shaped design. Read analog signals from the feedback
circuit and adjust PWM output accordingly Controls LEDs MCU Requirements
PWM outputs for each coil A/D converters for each coil feedback
Possible Choices: ARM A series ATXmega64
Willuweit
Amplifier Circuits Driver Amplifier
A class D Amplifier Completely digital Input from the PWM
supplied from theMCU
Energy efficient
High Gain Amplifier Op-amp with feedback
circuit Could also use a transistor
combination circuit
MCUPWMSignal
Coils
IGBT
IGBT
Grimes
The Cookware, the Coil and the Capacitors (LC Tank)
The coils act as an inductor When placed in series with capacitors,
the two form an LC circuit also known as an “LC Tank”
Grimes
Feedback Circuit Step-down transformer to supply 5V back to
the MCU Measures analog voltage signal from LC tank MCU adjusts frequency of the PWM signal
supplied to the IGBTs Frequency will begin high (60kHz) and
decrease down to potentially 19kHz When the voltage amplitude peaks and is
measured by the MCU, the frequency is maintained and the optimum power transfer has been reached
Grimes
Power Supplied with 120/240 AC voltage from
the wall outlet Rectified to a DC voltage of 5V and 15V
for the MCU and analog components Transform the 15V to 325V DC to be
supplied to the IGBTs PWM signal controls the “on/off” state of
the transistors creating an effective square wave AC signal.
Grimes
Power Transfer The alternating square wave from the
IGBTs creates an alternating magnetic field in the copper coils
The field is directed into the cookware, inducing eddy currents Each individual coil will create a portion of
the overall field necessary to heat the cookware
The number of coils needed varies with the cookware size
Grimes
Power Requirements With a 22 cm diameter iron pot on top of
range, the system will deliver approximately 2500 watts At an input of 60Hz Frequency supplied to the coils is 25kHz At a 100 peak-to-peak current to the coils
This would be divided between seven coils accordingly
Flodberg
Feasibility Materials
Availability/ Creation of copper coil windings
What kind of surface? Existing surfaces are Ceran
Combination of glass and ceramic Sensors sensitivity to temperature
Power Ability of small coils to generate energy
equivalent to the large coils
Flodberg
Member RolesTasks Ahmad
Alawadhi
EricWilluweit
Kegan Grimes
KyleChessman
SeanFlodberg
Software Design
MCUFeedback
DebuggingHardware Design
SensorsDrivers/
AmplifiersPower SupplyCopper
coilsDebugging Flodberg
Timeline
Flodberg
QUESTIONS