1

Critical Design Review

Team Iron ChefsAhmad Alawadhi

Eric WilluweitKegan GrimesKyle ChessmanSean Flodberg

Eric

2

CDR Agenda The Design

Project Status and Goal

Eric

3

The Design

Eric

4

PDR Review Sense (appropriate ferromagnetic)

cookware.

Turn on a PWM signal and LED indicator to corresponding coils.

Test multiple types of sensors Photodiodes, induction, infrared, and

pressure mapping

One coil sub-system

Eric

5

Concept OverviewAdjusted approach

Hardware and Software Interaction

Sub-systems Sensor Power Stage Gate Stage Feedback

Eric

6

Adjusted approach Utilize seven smaller copper coils in place of a

large single coil. Sense cookware’s location on the range via

induction sensing. Supply power to the coils that sensed the

cookware.

Eric

7

System Flow Diagram

Eric

8

Preliminary Sub-system Implementation Systems

Indicator LEDs Sensors Copper coils

Eric

9

Current Sub-system Implementation Systems

Indicator LEDs Induction sensing Power Supply

Resonant Circuit Gate Driver Microcontroller

Eric

10

LED Indicator Sub-system

Kegan

11

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 cookware the knobs correspond to.

Kegan

12

LED Location

LEDs onEach coil has at least five LEDs

LEDs off

Kegan

13

LED Use Cases

LEDs on

LEDs off

Kegan

14

LED Use Cases

LEDs on

LEDs off

Kegan

15

LED Use Cases

LEDs on

LEDs off

Kegan

16

Sensor Sub-system

Kegan

17

Sensor Sub-system Circuit

Coils are also used as induction sensors.

• Placing ferromagnetic cookware above the coil, its measurable impedance changes .

• Impedance change, affects measurable power.

Kegan

18

Sensor Sub-system Circuit

A bridge rectifier and low pass filter turns the AC signal across the coil into a DC signal.

Kegan

19

Sensor Sub-system

The DC signal is fed into an analog to digital converter to be processed by the microcontroller.

When the voltage across the coil drops below a threshold, the LED turns on and a varying frequency PWM is initiated.

Kegan

20

Testing Potential Sensors

Photodiodes Induction sensing Infrared LEDs Pressure sensing /

Mapping

Kegan

21

The “Transitron” JB Saunders A three terminal device Light enters the base region and

causes electrons to be injected into the emitter.

Kegan

22

Transitron Evaluation Voltage change of only ~10mV Fed into an Op-Amp Amplified signal fed to ADC on the

Arduino Uno (used for demo) Turned on the LED when transitron is

covered

Kegan

23

Transitron Pros and Cons Pros

Inexpensive Availability Easy Implementation

Cons Requires an amplifier Unreliable Cover with ANY object and the coil supplies

a magnetic field

Kegan

24

Consensus:

No thank you, transit-tron

Kegan

25

Total Circuit Simulation

Sean

26

Sean

27

Power Supply

Sean

28

Input Power 120VAC at 60Hz

Common mode choke Bridge Rectifier

Sean

29

Gate Circuit

Sean

30

Gate Drivers High power IGBTs

Sean

31

Power IGBTs

ON Voltage – 15V Supplied from gate driver

Rated For: 1200V 40A

Reverse conduction diode Heat:

Cool using an aluminum heat sink

Sean

32

Resonant Tank

Sean

33

SW

Matching Impedance LC Tank:

Resonant Frequency Matches switching

frequency with resonant frequency to maximize power output

Sean

34

Sean

35

Testing Hardware Variable Auto-Transformer Audible IGBT switching

Cast iron pan warmed up Observed Risks

Current regulation 8 fuses blown

Capacitor sustaining charge

Sean

36

Microcontroller

Kyle

37

HW-SW Bridge TOPREF – Top reference SWREF – Feedback

Compare the two references

PWM

Kyle

38

Texas Instruments C2000 Output:

Seven PWM signals for the final design A variable frequency PWM to

find resonance of cookware and contents

LED power to covered coils Input:

Read analog signals through ADC from the feedback circuit and adjust PWM output accordingly

Additional: Check resonant frequency

approximately every 10 seconds

Kyle

39

Results

Kyle

40

Induction Sensor

No cookware: 3.2VDC With 15in cast iron pan over coil:

1.77VDC With 6in aluminum pot over coil:

1.69VDC

Set ADC threshold to turn on LED and supply PWM only for cast iron pan

Kyle

41

Coil without cookware

Kyle

42

Coil with 15” Cast Iron Pan

Kyle

43

Prototype BoardCommon Mode Choke

IGBTS

Driver Circuit

Resonant Tank

Bridge Rectifier

Ahmad

44

Analog Feedback Circuit

Ahmad

45

Complete One Coil System

Ahmad

46

Future Milestones Finish one-coil subsystem Design seven-coil system Design software to accommodate seven

coils Integrate subsystems

Ahmad

47

Potential Risks

Magnetic Field Connecting to mains Probing High voltages High current pollution back to the auto-

transformer

Ahmad

48

Spent BudgetItem Quantit

yPrice

1200V, 40A, IGBTs 4 $23.84

NPN Transistor 3 $1.02

PNP Transistor 2 $2.14

Voltage Regulator 2 $4.04

Burton Single Coil Stove 1 $79.95

Photo-sensors 4 ~$4.50

Assorted Capacitors and Resistors NA Harvested

Half bridge High voltage Driver Chip 3 $6.45

Total $121.94

Ahmad

49

Preliminary Parts ListItem Quantit

yCost

Litz Wire – 32AWG, ~900 strand

~200ft Currently uncertain

TI-C2000 1 $0.00 - Given

High Voltage Capacitors ~20 ~$100.00

Ferrite Core Wound Inductors ~10 ~$60.00

PCB 2 ~$80.00

Fuses ~10 $20.00

Ceran Top 1 ~$100.00

Frame 1 Currently uncertain

Total ~$400.00

Ahmad

50

Updated Schedule

Ackhmad

51

Member RolesTasks Ahmad

Alawadhi

EricWilluweit

Kegan Grimes

KyleChessman

SeanFlodberg

Software Design

C2000

Feedback

Debugging

Hardware Design

Sensors

Power Supply

Gate Circuit

Resonant Circuit

Debugging

Primary

Secondary

Ahmad

52

QUESTIONS?

Ahmad