Critical Design Review Team Iron Chefs Ahmad Alawadhi Eric Willuweit Kegan Grimes Kyle Chessman Sean Flodberg 1 Eric

CDR Agenda  The Design  Project Status and Goal 2 Eric

The Design 3 Eric

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 4 Eric

Concept Overview  Adjusted approach  Hardware and Software Interaction  Sub-systems  Sensor  Power Stage  Gate Stage  Feedback 5 Eric

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. 6 Eric

System Flow Diagram 7 Eric

Preliminary Sub-system Implementation  Systems  Indicator LEDs  Sensors  Copper coils 8 Eric

Current Sub-system Implementation  Systems  Indicator LEDs  Induction sensing  Power Supply  Resonant Circuit  Gate Driver  Microcontroller 9 Eric

LED Indicator Sub-system 10 Kegan

 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. 11 Kegan

LED Location LEDs on Each coil has at least five LEDs LEDs off 12 Kegan

LED Use Cases LEDs on LEDs off 13 Kegan

LED Use Cases LEDs on LEDs off 14 Kegan

LED Use Cases LEDs on LEDs off 15 Kegan

Sensor Sub-system 16 Kegan

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. 17 Kegan

Sensor Sub-system Circuit A bridge rectifier and low pass filter turns the AC signal across the coil into a DC signal. 18 Kegan

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. 19 Kegan

Testing Potential Sensors  Photodiodes  Induction sensing  Infrared LEDs  Pressure sensing / Mapping 20 Kegan

The “Transitron”  JB Saunders  A three terminal device  Light enters the base region and causes electrons to be injected into the emitter. 21 Kegan

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 22 Kegan

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 23 Kegan

Consensus: No thank you, transit-tron 24 Kegan

Total Circuit Simulation 25 Sean

26 Sean

Power Supply 27 Sean

 Input Power  120VAC at 60Hz  Common mode choke  Bridge Rectifier 28 Sean

Gate Circuit 29 Sean

 Gate Drivers  High power IGBTs 30 Sean

Power IGBTs  ON Voltage – 15V  Supplied from gate driver  Rated For:  1200V  40A  Reverse conduction diode  Heat:  Cool using an aluminum heat sink 31 Sean

Resonant Tank 32 Sean

SW 33  Matching Impedance  LC Tank:  Resonant Frequency  Matches switching frequency with resonant frequency to maximize power output Sean

34 Sean

Testing Hardware  Variable Auto-Transformer  Audible IGBT switching  Cast iron pan warmed up  Observed Risks  Current regulation  8 fuses blown  Capacitor sustaining charge 35 Sean

Microcontroller 36 Kyle

 HW-SW Bridge  TOPREF – Top reference  SWREF – Feedback  Compare the two references PWM 37 Kyle

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 38 Kyle

Results 39 Kyle

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 40 Kyle

Coil without cookware 41 Kyle

Coil with 15” Cast Iron Pan 42 Kyle

Prototype Board Common Mode Choke IGBTS Driver Circuit Resonant Tank Bridge Rectifier 43 Ahmad

Analog Feedback Circuit 44 Ahmad

Complete One Coil System 45 Ahmad

Future Milestones  Finish one-coil subsystem  Design seven-coil system  Design software to accommodate seven coils  Integrate subsystems 46 Ahmad

Potential Risks  Magnetic Field  Connecting to mains  Probing High voltages  High current pollution back to the auto- transformer 47 Ahmad

Spent Budget ItemQuantityPrice 1200V, 40A, IGBTs4$23.84 NPN Transistor3$1.02 PNP Transistor2$2.14 Voltage Regulator2$4.04 Burton Single Coil Stove1$79.95 Photo-sensors4~$4.50 Assorted Capacitors and ResistorsNAHarvested Half bridge High voltage Driver Chip3$6.45 Total$ Ahmad

Preliminary Parts List ItemQuantityCost Litz Wire – 32AWG, ~900 strand~200ftCurrently uncertain TI-C20001$ Given High Voltage Capacitors~20~$ Ferrite Core Wound Inductors~10~$60.00 PCB2~$80.00 Fuses~10$20.00 Ceran Top1~$ Frame1Currently uncertain Total~$ Ahmad

Updated Schedule 50 Ackhmad

Member Roles TasksAhmad Alawadhi Eric Willuweit Kegan Grimes Kyle Chessman Sean Flodberg Software Design C2000 Feedback Debugging Hardware Design Sensors Power Supply Gate Circuit Resonant Circuit Debugging Primary Secondary 51 Ahmad

QUESTIONS? 52 Ahmad