1 / 18

Back-up Power Supply

Back-up Power Supply. Chris Hopfinger Kevin Rogers December 4, 2003. Motivation. Relates to our specific field of study. We wanted to design a cheaper back-up power supply for a motor. Most of the back-up power supply’s are not specifically designed for use with a motor, just general loads.

lilika
Download Presentation

Back-up Power Supply

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. Back-up Power Supply Chris Hopfinger Kevin Rogers December 4, 2003

  2. Motivation • Relates to our specific field of study. • We wanted to design a cheaper back-up power supply for a motor. • Most of the back-up power supply’s are not specifically designed for use with a motor, just general loads.

  3. Objectives • To use cheap and simple components to create a power supply for a motor. • Keep motor operating smoothly through the transition from power grid to battery back-up.

  4. Design Considerations • Motor needs a consistent input waveform to operate properly. • Run motor with a 12 volt battery • Need a delay before switching back to the ac line to resynchronize the motor and ac line.

  5. Block Diagram

  6. Phase-Lock Loop

  7. Integrator • Basic integrator circuit. • R and C determined by the time constant of VCO • 1/RC=.05 • Choose R=1k and C=50uF

  8. VCO Tests • ICL8038 chip • Test VCO to determine how to make frequency change. • Vary current into pins 4 & 5

  9. Phase Lock Loop Tests • Test the PLL as a whole. • When the two waveforms were compared their periods had very small error, ~ 1 us. • Phase and Frequency locked over the range of 40-65 Hz.

  10. Inverter Design

  11. Inverter Gate Drives • 1. 1k Hz triangle wave produced by VCO • 2. Modulation function, M(t), from Phase-Lock-Loop • LM311N compares waveforms 1 and 2 outputs 4V logic

  12. Inverter Test

  13. Inverter Tests

  14. Switches Power Relays too expensive and Ideal Switches do not exist • Attempted to use MOSFETS • Rectified Line voltage for control of MOSFETs

  15. Accomplishments • VCO locked with reference frequency • Reasonable output from the inverter

  16. Challenges • The phase comparator was impossible to locate, so one had to be built with NAND gates. • MOSFETs couldn’t be used as in line switches. • Inverter current ratings.

  17. Possible Improvements • Add 12V/170VDC boost-converter to eliminate need for transformer at output of inverter • Add SCR Diode bridge for switching between ac line and inverter • Improve oscillator waveform quality • Improve filtering of higher end frequencies

  18. Questions? Any Questions? We would like to thank all those who aided us with our project, especially Mark Weigert and Prof. Krein.

More Related