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Selection of DC motors for EV and controlling them

  1. Apr 3, 2008 #1
    Hi, I am designing a small EV and I am looking forward to some guidlines regarding designing of H-bridge (torque) controller for controlling somewhat in between 6-8 permanent magnet brush DC motors , the overall power required from these motors is between 70 to 250 W, where 70 W is for propelling EV on normal surface and 250 W for peak/climbing uphill requirements.

    Could you please suggest me the cheapest controlling design for such operation like
    a) which type(with particular specs) of the bunch of small pmdc motors best fit for such operation (here the torque requirement is around 20 N-m) and i want to run all motors (say parallel combination) with a constant speed and controlled torque(preferable). The supply is 12V from batteries.
    b) How to design and what is the best and the cheapest torque controlling method of these motors using H-bridge (like providing a common reference or say separate torque control of each motor and providing those with a common reference), the types of Mosfets and the heat sinks. Keeping in mind the availability in the market and the price factor too.

    If you have any questions regarding this please ask me. All suggestions and ideas are welcome. Any help would be of great help!!!

  2. jcsd
  3. Apr 4, 2008 #2


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    You only need an H-bridge if you want to reverse motor rotation.
    Pulse width modulation is probably what you need to look up for torque control.

    If you're looking for motors to meet your specs you might try Digikey.com or Jameco.com.
  4. Apr 7, 2008 #3
    Thanks for the help No Time.

    Well I am particularly looking for controlling the torque of bunch of small DC motors operating in parallel, with a torque of say 5N-m for each small motor.

    I am also looking for some idea to control these motors using Hbridges in the cheapest and non bulkier way as i dont have much space to afford Hbridge controller for each motor separately or to provide torque reference separately to each motos, looking for something like controlling say 2 motors with a common Hbridge or something like that.........

  5. Apr 8, 2008 #4


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