motor controller for a 48v bldc motor

Discussion in 'The Projects Forum' started by ncccengineering, Nov 20, 2013.

  1. ncccengineering

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    Nov 20, 2013
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    I am working on a school project and i'm working with a design team to make a simple motor controller for a 48v 40a bldc motor. We are just a high school class and have no experience with this topic. Anything you could do to point us in the right direction would be great.
     
  2. ronv

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    Nov 12, 2008
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    That's a project that can smoke a lot of expensive parts.:eek:

    You can go to one of the major suppliers like Mouser or Digikey and look under power management for brushless motor controllers. You need to tell us more about your motor. A spec. would be best. But for sure the number of phases and if it has sensors or not.
     
  3. MaxHeadRoom

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    Jul 18, 2013
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    The Picmicro site has info on BLDC control or the Freescale (Motorola) semi site has dedicated IC's for this application.
    Typically you would have hall effect commutation, or at least the equivalent tracks on the encoder, if fitted.
    40amp motor is fairly large!
    Max.
     
  4. ncccengineering

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    Nov 20, 2013
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    This is the specs from the website we bought it from:
    Electric trike motor brushless 48V/60VDC 750W
    The 48V 750W brushless dc tricycle motor main specification:
    No load current: ≤5.0A
    Rated power:750W
    Rated speed:2800RPM
    Rated torque:2.56N.m
    Rated current:≤20A
    Efficiency:80%
    Ratio: 6:1
    Real speed:480RPM
    Weight:6.8KG
    Motor phase angle:120℃
    Motor dimension: 26CM*13*CM*15.5CM
    Load Capacity:500KG

    [​IMG]

    This is for the 48V 750W brushless motor.
     
  5. ronv

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  6. ncccengineering

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    We have to build one for the design challenge. Cost isn't a big issue either.
     
  7. ronv

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    Ahh, I see.

    OK. So a couple more questions:
    Does it need to go in forward and reverse or just forward?
    Somewhere I thought I saw the wiring for the plug, but I can't seem to find it again. It had hall sensors, but I can't remember the voltage for the hall sensors.
    I seems to be a 3 phase motor (120 degrees).
    How will you control it? With a micro controller or do you just want a control to adjust the speed (like a volume control)?
     
  8. shortbus

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    Or you could make one using the MC33035 -
     
  9. ronv

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  10. ncccengineering

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    Nov 20, 2013
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    This motor only has to go in forward.We do not care about going in reverse. I do not know what you mean by "wiring for the plug." Also, I was unable to find anything about hall sensors. The specs that I put in a previous post is all that I am aware that we have.

    Would this be an acceptable IC : http://www.apexanalog.com/wp-content/uploads/2012/10/SA306U_H.pdf

    This was offered as an idea earlier: http://www.mouser.com/ProductDetail...KVeH05n7DA==&gclid=CPKirInF-LoCFQbl7AodUUoArQ But my team and I could only find a pwm input not an output.

    We aren't dead set on a pwm; however, we feel that it is the most efficient. Any advice that you can offer is a HUGE help!
     
    Last edited: Nov 22, 2013
  11. Alec_t

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    No. Its rated current is only 15A.
    The PWM input defines the duty cycle and frequency. The six Ho and Lo outputs convey the necessary PWM drive signals to the high and low side FETs.
     
  12. ronv

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    By plug I mean the diagram that describes what each of the wires coming out of the motor is used for. It's on the internet somewhere, but you can look for it as easy as I.
     
  13. ncccengineering

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    Nov 20, 2013
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    Yes we have found that diagram. We actually have the motor in our possession along with its motor controller; however, for our competition we have to purpose design and build our own motor controller. We can't buy one off the shelf. (We do have the motor and controller hooked up and we know what each wire is supposed to do.)
     
  14. ncccengineering

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    So does that specific IC actually do PWM ?
     
  15. ronv

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    You need to provide the pwm input along with forward reverse enable and such.
    So can you post a link or a picture of the motor wires?
     
  16. MaxHeadRoom

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    I assume you are looking for PWM control signal and also PWM motor power switching?
    Max.
     
  17. ncccengineering

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    Attached is the diagram we have for the wires coming out of the motor. If you would like I can attach a picture of the motor, but I felt like this was more helpful.
     
  18. ncccengineering

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    Yes this is correct.
     
  19. Alec_t

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    The PWM and direction control signals would typically be provided using a micro. A suitable PWM signal could also easily be generated by a conventional 555 circuit.
     
  20. ncccengineering

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