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Life’s Ultimate Problem…

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.

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Life’s Ultimate Problem…

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  1. Life’s Ultimate Problem… Solved By…

  2. Preliminary Design Review Ahmad Alawadhi Eric Willuweit Kegan Grimes Kyle Chessman Sean Flodberg Team Iron Chefs

  3. Overview • Project Objective • Background • Approach • Sub-system Implementation • Member Roles • Schedule • Contingency Plan Chessman

  4. 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

  5. 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

  6. 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

  7. 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

  8. Inputs and Outputs Alawadhi

  9. System Flow Diagram Alawadhi

  10. Sub-system Implementation • Systems • Indicator LEDs • Copper coils • Sensors Alawadhi

  11. 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

  12. 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

  13. 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

  14. 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

  15. Testing Potential Sensors • Photodiodes • Induction sensing • Infrared LEDs • Pressure sensing / Mapping Willuweit

  16. 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

  17. Amplifier Circuits IGBT • Driver Amplifier • A class D Amplifier • Completely digital • Input from the PWM supplied from the MCU • Energy efficient • High Gain Amplifier • Op-amp with feedback circuit • Could also use a transistor combination circuit MCU PWM Signal Coils IGBT Grimes

  18. 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

  19. 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

  20. 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

  21. 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

  22. 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

  23. 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

  24. Member Roles Flodberg

  25. Timeline Flodberg

  26. QUESTIONS

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