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Thread: Oscillating current & auto dutycycle control

  1. #11
    Join Date
    Feb 2012
    Location
    Kerala, India
    Posts
    34
    What I intend to do is to make a resonant tank circuit and see if we can achieve maximum efficiency. Since the primary coil current for the coupling transformer/resonant-choke is minimal, have chosen to use a low power H-bridge, L298 (max 4 amps).

    Just completed the schematic layout for this project. A microprocontroller will generate a low frequency (say, 0.5Hz @ 50% duty cycle) and then the polarity is alternately reversed by the H-bridge and provided to the coupling transformer at a high frequency (close to resonant frequency of a water cell). I plan to initially vary this frequency manually and later will think about automating it eg; scan through a frequency window and lock itself at resonance. In the circuit I have separated the logic voltage and the drive voltage for coil excitation. The excitation voltage can be from a variable power source (9 to 24VDC) whereas the logic voltage (for the microcontroller etc will be derived from it at 5VDC.

    H-bridges that are cheap and affordable,

    1. L298, dual and when run in parallel can handle upto 4amps
    2. VNH2SP30, can handle upto 30amps.

    You can get them from ebay. I am now searching for a suitable core to fabricate the coupling transformer.

    RTJ Nair

  2. #12
    Join Date
    Nov 2009
    Location
    San Diego, California.
    Posts
    337

    How is your work going?

    I would just like to point out that electrolysis cells have a duality of nature as electronic devices. They are capacitive until electrolysis starts at which point they become variable resistors.

  3. #13
    Join Date
    Jun 2012
    Posts
    14
    Google for "fuel cell"
    and learn more about it

  4. #14
    Join Date
    Nov 2009
    Location
    San Diego, California.
    Posts
    337
    Quote Originally Posted by jim131 View Post
    Google for "fuel cell"
    and learn more about it
    I was referring to the work of RTJ_Nair.

    Fuel cells, I know about.

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