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hsklkk
Joined: 29 Jun 2008
Posts: 19
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 04 Jul 2008 16:17 question about step up hihg power DC DC converter? |
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Background:high power DC DC converter 4kW(96V->200V)
For Electric Vehicle drive
Accept 4 quadrant control
Last edited by hsklkk on 29 Sep 2008 7:42; edited 1 time in total |
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sabeti_1990
Joined: 16 Nov 2007
Posts: 100
Helped: 4
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| 27 Sep 2008 8:45 Re: question about step up DC DC converter? |
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hi
U must to use a push pull system in 20khz frequency to this step up
very very be careful because U choice a big range of power
most lose & hardest section is on primary of your transformers because U have big snober
U don't need H bridge it use just for dc to ac
be success 
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tanuki
Joined: 11 Jun 2001
Posts: 90
Helped: 3
Location: Spain
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| 27 Sep 2008 17:43 Re: question about step up DC DC converter? |
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"high power DC DC converter 4kW ...96V to 200V
1) Push-Pull converter is best.
96V is moderate voltage for power FETs, Push-Pull has advantage of two low side switches (FETs).
2)full bridge only for forward converter?
Push-Pull has same performance as full-bridge with half the number of FETS.
4) have circuit design?
Circuit schematics of similiar power on the web.
5)forward converter can be used for step up? Yes. Output voltage depends on transformer winding ratio.
6)what is the most difficult part of this converter?
Transfomer design. Integrated magnetics (Planar transformers) may be the easiest since one needs only the cores. Since planar cores have high surface to volume ratio, better cooling allows higher frequency operation ... around 250KHz.
7)major loss = ? Generally losses are highest in the power FETs. However a good design balances losses across all of the power components.
8)Output rectification ... synchronous FETs.
At the output voltage and current levels ... synchronous FETs provide the best performance.
Good luck, hope this is not your first design at this power level.
Example current mode PWM controller:
http://www.national.com/pf/LM/LM5030.html
or a cascaded current mode controller:
http://www.national.com/pf/LM/LM5041A.html
Planar transformer catalog at: http://www.paytongroup.com/
Planar cores:
http://www.mag-inc.com/pdf/2006_ferrite_catalog/2006_planar_e_i_cores.pdf
http://www.ferroxcube.com/
Articles:
http://www.magneticsmagazine.com/e-prints/bloom.pdf
http://powerelectronics.com/mag/power_planar_magnetic_technology/
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hsklkk
Joined: 29 Jun 2008
Posts: 19
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| 28 Sep 2008 17:22 question about step up DC DC converter? |
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| but my proposed converter is required to accept four quadrant control of motor, so, i think the full bridge is a must
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tanuki
Joined: 11 Jun 2001
Posts: 90
Helped: 3
Location: Spain
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| 28 Sep 2008 22:49 Re: question about step up DC DC converter? |
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There was perviously no mention of a motor control.
Is there regenative braking?
You need to specify more completely what you need and want help for.
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hsklkk
Joined: 29 Jun 2008
Posts: 19
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| 29 Sep 2008 7:40 question about step up DC DC converter? |
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| oh...sorry, let me modify the post first
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tanuki
Joined: 11 Jun 2001
Posts: 90
Helped: 3
Location: Spain
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| 29 Sep 2008 15:36 Re: question about step up hihg power DC DC converter? |
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Ok, EV motor control.
Regardless of the SMPS topology, the SMPS must be bidirectional, i.e. able to move power in either direction, to the load or from it.
Most SMSP topologies can be converted to bidirectional operation so Full Bridge is not the only solution. It is a matter of magnetics cost versus switch cost and other complexities.
If no galvanic isolation is required, it is possible to design without a transformer, using only inductor(s). Using a tandum Buck-Boost configuration ... similiar to a Class-D amplifier (but bidirectional and maybe multi-phase).
For modern results, I think the overall project requires an advanced design and considerable skills. There are several books, journals and magazines dedicated to the subject ... as well as numerous companies designing and selling these types of controllers. Buying what you need might be your best plan.
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