I think the most efficient approach would be to use motors that are rated
for the battery voltage. Failing that, I suspect a bridge switcher driving
a transformer is the most efficient way to get a relatively high power to
a higher voltage. A typical boost converter (which I consider a form of a
"flyback converter") becomes impractical above 100 or 200 watts.

Harold

> On Sunday 24 September 2006 10:46, Xiaofan Chen wrote:
>> What is the requirement for the boost converter? For example,
>> the input and output voltage, the efficiency requirement. Depending on
>> the requirement, the design will be totally different.
>
> Input is automotive voltage -- say 10V to 14V.  Output is approx 20V, and
> the
> higher current will be used to power some motors.  Efficiency is "as
> efficient as possible, within reasonable cost".  It's not a portable
> battery-powered device, so it does not have to be 99% efficient, yet,
> given
> the current requirement, I'd like it to be as efficient as possible so
> that
> there's less heat to be dissipated.  I know that's very shady, but I'm not
> familiar with the high-current design, so I would evaluate various
> efficiencies vs. cost ... that is, IF I have choices.
>
>
>> 50A is not small current. 50A @3V will be 150W. 50A@24V will be
>> 1.2kW and the design approach will be very different.
>>
>> The design which fits 1A@3V will not fit for the design of 50A@3V
>> since the loss on the diode will be too much and you may have to use a
>> synchronous boost design.
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