How do you regulate 36V DC?

Discussion in 'The Projects Forum' started by liquidphire, Apr 2, 2009.

  1. liquidphire

    Thread Starter New Member

    Apr 2, 2009
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    I am building an electric scooter out of an engine that i have. i have bought the three 12V 12Ah batteries and connected them in series to produce 36V. all i need is a way to regulate that voltage to the motor in order to produce my throttle body. How can i regulate this?
    I have moderate expeirence in electronics and i am capable of doing any soldering that the job may require, but I am not sure what to even look for. any suggestions would be helpful.
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    What are the electric motor specifications?

    Have you considered buying an "off-the-shelf" control unit compatible with the motor, rather than building this yourself? It might be more reliable and less frustrating in the long run.
     
  3. liquidphire

    Thread Starter New Member

    Apr 2, 2009
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    It looks like i need something that can handle at least 36V and 20 amps. i am considering buying something off the shelf, but if costs negate that option, then i will build something.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
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    Building somethong will be quite expensive too and it won't be as good as one off the shelf.
    Anyway, you have to use PWM to control the speed of your motor. A simple circuit with a 555 is here:

    http://www.dprg.org/tutorials/2005-11a/index.html
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I did a quick search on DigiKey for high voltage, H-bridge drivers. There are several options, such as the Freescale 33883. Such a driver allows typical 5V control as from any MCU or other PWM generator and will drive your mosfets running at 36 or higher voltage.

    As for a pre-packaged PWM generator/motor controller at that voltage and current, DigiKey had only two. They were about $600 to $800 each just for the device.

    You can try the DigiKey or any other supplier's parametric search engine to narrow your choices.

    As for cost, it is hard to judge without knowing how many mistakes you might make in getting a working circuit. I would base any budget on burning up at least one set of mosfets and driver. Does your scooter need reverse? If not, you might get by with a half-bridge controller that would require only 2 or 4 (if paralleled) mosfets plus a driver and controller.

    John
     
  6. liquidphire

    Thread Starter New Member

    Apr 2, 2009
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    Thanks guys! that was all i really needed to know. I think i've found a solution ot my problem and ill post pictures when i'm done.. Thanks again guys, you've been really helpful
     
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