1 / 28

Power Melder Midterm Presentation

Power Melder Midterm Presentation. SEPTEMBER 25, 2008. About Us. Overview. Current Problem Solution Constraints Approach Power Hardware Microprocessor Progress Questions. Current Problem. Small generators can not power large loads. Solution. Parallel power generation.

casimir
Download Presentation

Power Melder Midterm Presentation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Power MelderMidterm Presentation SEPTEMBER 25, 2008

  2. About Us

  3. Overview • Current Problem • Solution • Constraints • Approach • Power Hardware • Microprocessor • Progress • Questions

  4. Current Problem • Small generators can not power large loads.

  5. Solution • Parallel power generation

  6. Current Solutions • Honda EU1000iA • 1 kW generator, may be paralleled • Input generators must be identical (same output power) • Must be Honda generators

  7. Economic Yamaha 2500 Watt Generator with Inverter Technology $1500 The Power Melder must cost less than a typical consumer generator with similar capacity. Subaru 1400 Watt Generator with Inverter Technology $1000 Mitsubishi 2500 Watt Generator $825 Images, Prices from: http://www.electricgeneratorsdirect.com

  8. Safety • Input Isolation • Fuses • Conductor Separation 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 Table from http://pcbwizards.com

  9. System Overview Power Melder Generator #1 Master uC PFC DC-DC Converter Generator #2 PFC DC-DC Converter Inverter

  10. Power Factor Correction • Power Factor • Ratio of real power to apparent power • Ideal situation • Unity power factor • Current replicates voltage (phase and shape) • Load appears purely resistive • No reactive power drawn

  11. Power Factor Correction • Bridge Rectifier • AC to DC • Non-linear current pulses • Poor power factor • More line current to produce same output voltage

  12. Passive Power Factor Correction Inductor used to shape input current Large inductor required for high power applications Increased weight Increased cost Unregulated output voltage Requires switch for multiple input voltages Active Power Factor Correction IC used to shape input current Low cost Convenient size Stable output voltage with small ripple Over-voltage protection Input current limiting Power Factor Correction

  13. Power Factor Correction Active PFC Passive PFC No PFC Image from: http://www.pcpower.com/prod_revs/pcp_silencer/Oscope_web.jpg

  14. Power Factor Correction • LT1249 Power Factor Controller • Peak current limiting • Over-voltage protection • 100kHz switching frequency • Low start-up current • No switch required for multiple input voltages

  15. Power Factor Correction Power Melder PFC Stage

  16. Power Factor Correction Input Voltage = 177VAC, 60Hz LT1249 Input Voltage/Current and Output Voltage/Current

  17. Power Electronics • Flyback topology. • Simple, Commonly used • Low parts count • High Ripple • Requires relatively large transformer Image from: http://www.powerdesigners.com/InfoWeb/design_center/articles/DC-DC/converter.shtm

  18. Power Electronics • Half-Bridge topology. • Relatively high power • Efficient • Large capacitor currents • Requires complex control circuitry Image from: http://www.hills2.u-net.com/electron/smps.htm

  19. Power Electronics • Full-Bridge topology. • Extremely high power • Very Efficient • Highest parts count • Requires complex control circuitry • No control circuitry fault tolerance Image from: http://www.hills2.u-net.com/electron/smps.htm

  20. Power Electronics • Double-switch forward topology. • Isolated (safe) • Efficient • Cost-effective • Medium power • Very uncommon Image from: http://www.stmicroelectronics.com/stonline/books/pdf/docs/3721.pdf

  21. Isolation Digital Control Lines • GALVANIC ISOLATION • Isolating functional sections of electric systems • Low speed • High power • Communication between multiple • OPTO-COUPLER (OPTO-ISOLATOR) • Uses a beam of light to transmit the signals or data across an electrical barrier • High speed • Low power • Small size • Achieves excellent isolation

  22. Opto-Coupler • Components of the Opto-Coupler • light emitting device • light sensitive device

  23. Analog to Digital Converter Used to sense input voltage of the generators LTC2309 • 12 bit resolution • I2C compatible • Low power: 1.5mW at 1ksps • Fast Conversion Time: 1.3µs

  24. Microcontroller • Microchip PIC24HJ32GP202

  25. MCU Firmware (Converter) Serial comm task Timer Interrupt ADC Interrupt Init frozen? Init task yes Wait for serial command Copy ADC value into memory no Signal init semaphore Wait on semaphore Process command Reset ADC Init PWM duty cycle and start PWM Main frozen? Return any requested data no Unfreeze main task and freeze init task Signal main semaphore

  26. MCU Firmware(Converter cont’d) Main task Calculate output voltage from ADC value Wait on semaphore Calculate input voltage from ADC value Voltage too high? yes Decrease PWM duty cycle Voltage too low? yes no Turn off PWM Voltage too low? yes Increase PWM duty cycle no Send message to master Voltage too high? no yes Freeze main task no

  27. MCU Firmware (Master) Main task Wait on semaphore Query current contributions Read voltage of ouput bus Contr. correct? yes Voltage too high? Send decrease command to all yes no Send correctional commands no Voltage too low? yes Send increase command to all no

  28. Questions?

More Related