How to build Bosst Converter ?

Discussion in 'The Projects Forum' started by Engjay, Mar 8, 2008.

  1. Engjay

    Thread Starter Member

    Mar 7, 2008
    14
    0
    hi everyone
    i need to build up a boost converter
    with input voltage 12v dc and output voltage 180v dc
    and around 7 amp output current
    is that possible with 12 v dc input or we need more voltage in?
    itswill be use for a dc motor with input voltage out to 180vdc maximum
    what kind of chip i need ?
    i need the schematic circuit with it vallues?
    plez i need your helps
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    You are taking on quite a challenge since the output power of you supply will be 7*180 or 1260 Watts. Even with a highly efficient boost converter you will need to input 1.5 Kilowatts.

    What are you powering with this supply?

    hgmjr
     
  3. Engjay

    Thread Starter Member

    Mar 7, 2008
    14
    0
    So What kind of Converter iam going to Use
    i need 180v with 7 amp current
    i need the circuit
    Can you help me to build up the circuit ????
    i can use more input voltage max to 36vdc max (3 battries )

    i need it for the dc motor of course iam going to Use A Voltage controller
    and (potentio meter )
     
  4. hgmjr

    Moderator

    Jan 28, 2005
    9,030
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    1500/12 equates to 125 Amps at the input of your supply. That is a hefty amount of current.

    I am not familiar with any components that can switch that amount of current.

    hgmjr
     
  5. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    One bought from a professional power supply designer. All joking aside... Like hgmjr mentioned you are tallking about 1500 Watts assuming you have an 85% efficient converter-- which is 'really' an assumption for a fivefold high current boost. This is irregardless of whether you are using 12V or 36V input. Even with 36V input you are still looking at >35A input current. You are going to have to have monster sized components.

    Maybe after you tells us the application someone might have a solution -- paralleling or multi-phase etc..
     
  6. Engjay

    Thread Starter Member

    Mar 7, 2008
    14
    0
    So What should I do
    Do You have any opinion for my Project
    Iam Going To Buld Up an electric car
    I got the dc motor with 180v max
    and series 3000 and 1.5hp
    the problem that i have
    i dunno how to get 180v
    and how Can i move the car
    Where can i find a dc motor controller since the tradmill controller is useless becuse it take the ac part and i need dc
    can you give me suggetions
     
  7. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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  8. S_lannan

    Active Member

    Jun 20, 2007
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    although the figures match up i doubt that inverter is good for driving motors, most of those inverters strictly say not to use motors with them.
     
  9. thingmaker3

    Retired Moderator

    May 16, 2005
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  10. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
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    For that kind of voltage increase, you will definitely need to use a flyback-boost typology. I have designed a 1KW boost converter for a car amplifier, I will try to find a schematic around.

    You must come up with something slick to handle the 125A you will encounter. Probably looking at copper bus-bars of some sort. You can find MOSFETs that can handle that kind of current, but you are better off using paralleled FETs. These larger FETs will require a decent gate driver, probably in the order of 4 or more amperes sink/source. You do not want to be operating in the linear region for long with that sort of current, it will fry the FETs in no time.

    I would pick up a good book in transformer design. You will probably end up with many parallel strands of an easy to wind magnet wire gauge for the primary.

    Good luck

    Steve
     
  11. Engjay

    Thread Starter Member

    Mar 7, 2008
    14
    0
    our instructor
    dont want us to use inverter
    he want us to use buck -boost converter (dc-dc) at least 4 battries
    48 vdc input to 180 vdc with 7 amp current output
    where can i find a good dc motor controller
    do you have a good sites
    help me for this
     
  12. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    As has already been pointed out, a buck-boost converter for that current will not be easy. Ask your instructor for some hints. John
     
  13. Engjay

    Thread Starter Member

    Mar 7, 2008
    14
    0
    Can you Give ME a good prove its will not work So i can tell our instructor it will not be easy so we can use inverter instead
    i will be greatful for u guys
     
  14. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    The manual for that particular inverter does not include a restriction against motors. In fact, it says power tools can be used.

    However, that is not really the point. The motor being used by the OP is a brushed DC motor that comes with its own rectifier and controller. Thus, even though the sinewave quality from a cheap inverter may be poor, it's going to be converted back to DC.

    The OP now reports that they are required to design and build a buck-boost converter that will produce approximately 2 kW at 180 VDC from 12-V storage batteries. That apparently has to be done before they can get on with the meat of the project, which seems to have somethig to do with robotics. Frankly, I think that is a bit ambitious for a one-year school project, and there seems to be a need to clearly define the scope and goal of the project. John
     
  15. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Go here and enter your specifications: Vin=12-14 V; Vout=180 V; Iout=10 A. Linear will respond that it can't help you. Of course, that doesn't prove it won't work...logically that is simply not possible to prove. A little searching, though, will show you it will not be easy with that topology.

    http://www.linear.com/pc/viewCategory.jsp?navId=H0,C1,C1003,C1042&gclid=COnbra-fgJICFSGWGgodBi6T9A

    John
     
  16. aaronl

    New Member

    Jan 1, 2008
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  17. scubasteve_911

    Senior Member

    Dec 27, 2007
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    aaroni,

    I don't think that is what he is after. I have taken a look at the OSMC in the past, it seems that they just build a fancy h-bridge controller. The OP seeks a boost converter for use as a motor driver.

    As for a reason why you shouldn't use a standard boost converter. You will need to operate the converter at a ~93.5% duty cycle. Extreme duty cycles impose inefficiently small off-times or low switching frequencies. Lower switching frequency causes higher ripple and requires larger magnetics.

    Steve
     
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