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    1.5kw DC to DC Boost Converter Circuit

    I want to build my own full bridge dc to dc converter with 12v in and 400v output for 1.5kw load
    I'll be using a sg3525ic to drive ir2113 mosfet driver, but I need help with a circuit layout. The only circuit I could find is this from tahmid.

    http://tahmidmc.blogspot.com/2013/01...2110-with.html

    This shows an input voltage of 300volt and that's why I'm uncertain if I can use this circuit for a 12 volt input?

    Will really appreciate some help.

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    Re: 1.5kw DC to DC Boost Converter Circuit

    Yes, you can.

    But for 1.5kw output, you will have a current of 125A; add some margin and get FETs that can handle 200A or so.

    Driver side may need only minor modifications. But what about the step up circuit? What kind of regulation you want?


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    Re: 1.5kw DC to DC Boost Converter Circuit

    Thanks for the confirmation.
    Another question, can I connect the mosfets in parallel on that circuit or can I only use the 4 mosfets as shown on the circuit?
    I'm planning to use irfp064n mosfets.

    - - - Updated - - -

    C_mitra , what do you mean by minor modifications?
    For my step up I will use e55 ferrite transformer and use the error amp on the sg3525 to regulate the voltage through a voltage divider circuit.



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Parallel circuit would be obviously necessary to build a 1.5 kW 12V input full bridge with IRFP064. You should particularly look at Rds,on and related voltage voltage drop. Better go for a 40V MOSFET like IRFP7430.

    Output current of IR2113 and similar drivers won't allow very fast switching, but it should be O.K. to keep switching losses of each transistor in a few watts range.


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    Re: 1.5kw DC to DC Boost Converter Circuit

    C_mitra , what do you mean by minor modifications?
    Follow the suggestions in #4 post.

    Fast turn on and turn off will reduce the losses but design and layout will be more critical. It is perhaps acceptable (is it?) to take 1-3% of the output power as switching losses.

    It is good to design for robustness even if you have to compromise some efficiency. But that is just an opinion.



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    Re: 1.5kw DC to DC Boost Converter Circuit

    here is some help with layout, which you also requested



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Quote Originally Posted by treez View Post
    here is some help with layout, which you also requested
    I can't see any attachments or what do you mean?



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    Re: 1.5kw DC to DC Boost Converter Circuit

    here is some help with layout, which you also requested
    PCB layout is an art and some consider it as a black art!

    Simple advice that may work sometimes: group blockwise and keep related blocks close.



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    Re: 1.5kw DC to DC Boost Converter Circuit

    woops sorry..here it is


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    Re: 1.5kw DC to DC Boost Converter Circuit

    Quote Originally Posted by FvM View Post
    Parallel circuit would be obviously necessary to build a 1.5 kW 12V input full bridge with IRFP064. You should particularly look at Rds,on and related voltage voltage drop. Better go for a 40V MOSFET like IRFP7430
    How many irfp7430 would I have to place on the full bridge for 1500 watt?



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Something that has not yet been mentioned that has a significant layout impact: thermal management.

    A newbie design (hard switching, non-optimized magnetics and other things) with such low input voltage and high power, you would be lucky to hit 80% efficiency. Most likely it will be lower.

    In other words, you would have to dissipate 300 or more watts of heat. That is a serious amount, even with forced air ventilation.
    My batteries are recharged by "Helpful Post" ratings.
    If you feel that I've helped you, please indicate it as a Helpful Post



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Thanks for all the great advise and tips and thanks for the attachment treez, it is very educational a lot of great info.

    One thing I noticed on the circuit and that I don't understand, is the Vdd voltage to the ir2113. Do I use the same Vcc voltage from the main supply voltage or where to I get the Vdd voltage from?



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Hi,

    VDD voltage is explained in the datasheet.

    Where to get it from?
    Somewhere from you application. But we don't know this. Usually the same supply as all the other logic circuitry.

    I recommend to read IR2113 related application notes.

    Klaus
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    Re: 1.5kw DC to DC Boost Converter Circuit

    Click image for larger version. 

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ID:	157278Click image for larger version. 

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    Is it normal for the voltage of the high side signal of the ir2113 to be higher than the low side?
    Also when I implement the voltage regulation on the sg3525 I get a distortion on both signals. What can this be because I'm running the full bridge now on 100% duty cycle.Click image for larger version. 

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ID:	157278



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Hi,

    Apparently you did not read IR2113vapplication notes...why not.
    They explain the voltages and they explain that 100% duty cycle is not suitable.

    Klaus
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    Re: 1.5kw DC to DC Boost Converter Circuit

    Instead of three blurry screenshoots, I would appreciate one clear photo.

    Not sure where you have 100% duty cycle, photos seem to show 50 %. A detailed explanation of implemented control pattern would be helpful.

    Is it normal for the voltage of the high side signal of the ir2113 to be higher than the low side?
    Surely, if you talk about gate voltages referred to ground. LO is low side Vgs, HO is high side Vgs + bridge output.

    Distortion, may be, which are you exactly talking about?



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Sorry I mean 50% duty cycle on each side of the bridge.



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Quote Originally Posted by FvM View Post
    Instead of three blurry screenshoots, I would appreciate one clear photo.

    Not sure where you have 100% duty cycle, photos seem to show 50 %. A detailed explanation of implemented control pattern would be helpful.


    Surely, if you talk about gate voltages referred to ground. LO is low side Vgs, HO is high side Vgs + bridge output.

    Distortion, may be, which are you exactly talking about?
    Click image for larger version. 

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    This is the clean signal without distortion or noise and yes I mean vgs Lo and Vgs HO which are the two signals I'm showing in the scope and on previous picture you can see the noise line running through the signals when voltage feedback is implemented.



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Hi,

    Photo: are you able to recognize:
    * Which channel is HO and which is LO
    * any timing information
    * the voltage setup
    * the voltage offset?

    How do you measure V_gs of high side? Do you use a diff probe?

    Klaus
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    Re: 1.5kw DC to DC Boost Converter Circuit

    if you measure the high side gate drive w.r.t. 0v then you will see the totem pole shift + the gate drive signal ...

    - - - Updated - - -

    you need a differential probe - or isolated scope to see just the high side gate drive ...



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