1. December 2nd, 2008 Power Melder Midterm Presentation

2. About Us Christopher Harper EE Power conversion electronics Tina McGlaston CPE Human- interfacing Daniel Wilson CPE Control Loops Human- interfacing Tyler Pettit EE Power-factor correction

3. Overview Current Problem Solution Constraints  Practical Constraints  Technical Constraints Progress Test Plan Questions

4. Current Problem Small generators cannot power large loads.

5. Solution Parallel power generation

6. System Overview Bridge rectifier Power factor correction μC Shunt resistor From generator Output bus ADC DC-DC converter Master/Slave bus DC-DC Converter Subsystem

7. Practical Constraint: Economic [1] The Power Melder must cost less than a typical consumer generator with similar capacity.

8. Practical Constraint: Safety Input Isolation Fuses Conductor Separation [2] Voltage Between Conductors ( AC Peaks or DC Volts ) Minimum Bare Board Spacing B1B2B3B4 …………… 301-5000.25mm (.01 in.)2.5mm (.1 in.)12.5mm (.492 in.)0.8mm (.0315 in.) …………… B1 - Internal Conductors B2 - External Conductors, uncoated, Sea level to 3050m ( 10K ft.) B3 - External Conductors, uncoated, over 3050m ( 10K Ft.) B4 - External Conductors, coated with permanent polymer coating

9. Technical Constraints NameDescription Input PowerMust accept 90-300V DC or AC 50-200Hz Output PowerMust provide a single output DC bus between 12V and 14.5V for use with an AC inverter Output StabilityMust be stable to within 10% of nominal value with a maximum of 10% ripple AccuracyMeasured power draw and power limiting must be accurate to within 10W Power CapabilityMust be capable of drawing 150W from any acceptable power source

10. Human Interfacing User Interface 4 line x 20 character LCD 12-key keypad for input User interface will allow the user input various information about the generators in use.

11. Human Interfacing 6 Menus/Screens  Home  Generator  Mode  Sharing  Power  Done # always takes user to Home menu * serves as ENTER button

12. Human Interfacing Home Menu  Displays operating mode of each generator  Displays output power of each generator  Displays total power of system

13. Human Interfacing Generator Menu  Allows user to select which generator to configure  User can always hit # to cancel and go back to Home Menu

14. Human Interfacing Mode Menu  Allows user to select whether the generator selected will operate in Sharing, Primary, or Backup mode  User can always hit # to cancel and go back to Home menu

15. Human Interfacing Sharing Menu  Allows user to set sharing percentage of selected generator  User can always hit # to cancel and go back to Home menu  User must hit * after finished

16. Human Interfacing Power Menu  Allows user to set maximum power to draw from selected generator  User can always hit # to cancel and go back to Home menu  User must hit * after finished

17. Human Interfacing Done Menu  Updates generator information and redirects user to Home menu

18. Human Interfacing User Interface Demo

19. Power Factor Correction First Hardware Prototype Completed CircuitAfter Failure

20. Power Factor Correction Re-constructed circuit Several failures Attempted to order new PFC chip (ML4821) Removed PFC from design Lost Input Voltage Range Technical Constraint

21. PCBs Layout for DC-DC Converter PCB Rectifier + Rectifier -

22. PCBs Layout for Master Controller PCB

23. PCBs Master Controller PCB Populated Master Controller PCB Converter PCB Power Melder PCBs

24. Enclosure Parts for Power Melder Enclosure

25. Test Plan - Subsystem Subsystem testing  Converter  different input voltages  too little power  different and varying loads  Master controller  keypad  LCD  different menu selections

26. Test Plan - System Test with…  one source (each converter)  failing source (not enough power capability)  different operation modes  Primary/backup  Percent sharing  varying loads  varying input voltages

27. Questions?