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Re: Achieving 98% efficiency in a boost converter, RIS-767

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On 2017-04-12 10:12, Winfield Hill wrote:
> legg wrote...
>>
>> On 19 Mar 2017 15:38:27 -0700, Winfield Hill
>> <hill@rowland.harvard.edu> wrote:
>>
>>> legg wrote...
>>>>
>>>> Winfield Hill wrote:
>>>>> Joerg wrote...
>>>>>>
>>>>>> If the MPPT is a required part of the game
>>>>>> you'd have to add in the Arduino power
>>>>>> consumption.  Maybe use a MSP430 instead?
>>>>>> Those can be operated on small drops of power.
>>>>>
>>>>> Of course.  But my rule is that none of the
>>>>> controller power consumption counts.  Why?
>>>>> We assume with effort you could drive that
>>>>> as far down as you want, but that's not
>>>>> the point.  The point is to achieve very
>>>>> efficient power conversion, period.  Any
>>>>> wild control scheme you dream up is OK.
>>>>
>>>> Scaling assumptions that approach an order
>>>> of magnitude are often troublesome.  Two
>>>> orders of magnitude will require more than
>>>> just serious thought.
>>>
>>> Yes, right.  And also bench experimenting.
>>> Hence my offer for free RIS-767 boards.
>>
>> What's the solar cell source unloaded output
>> voltage?  With 600mV loaded, I'd expect >900mV?
>> If so,
>>
>> https://datasheets.maximintegrated.com/en/ds/MAX17220-MAX17225.pdf
>
>   Right.  Quite a few boost converters claim to
>   achieve 95% under certain circumstances.
>   I purchased eval boards for about 10 of them,
>   but wasn't able to get better than 90% for my
>   2.0 to 2.4-volt boost.  One did 92-94% at 25mW
>   with 0.8 volts in, but strangely deteriorated
>   at 2.0 volts in.  In many cases it appeared the
>   eval board inductors were too small.  First,
>   too low a value, and second, too much core loss.
>   It seems the manufacturers just want to prove
>   how small their overall used space will be.
>
>   So I have footprints for about a dozen inductor
>   types.  I also wound an RM8-core inductor, that
>   measured to fit into a 98% budget (next post),
>   so I think that part of the scene is possible.
>
>   Another big part is the MOSFET's tradoff, for
>   Ron and Coss.  Low Ron goes along with high
>   Coss, and thus high C V^2 f losses.
>

This may be one of the rare occasions where GaN FETs might make sense.


>   Having a variable frequency with load, as the
>   Maxim parts do, helps out with that problem.
>

Unless there is zero stock a few weeks down the line :-)

-- 
Regards, Joerg

http://www.analogconsultants.com/

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Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-09 07:21 -0800
  Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-09 08:29 -0800
    Re: Achieving 98% efficiency in a boost converter, inducement Don Kuenz <g@crcomp.net> - 2017-03-09 21:30 +0000
      Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-09 13:59 -0800
        Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-10 05:30 -0800
    Re: Achieving 98% efficiency in a boost converter, deadline Winfield Hill <hill@rowland.harvard.edu> - 2017-03-10 05:34 -0800
      Re: Achieving 98% efficiency in a boost converter, deadline sea moss <danluster81@gmail.com> - 2017-03-10 21:10 -0800
        Re: Achieving 98% efficiency in a boost converter, deadline Winfield Hill <hill@rowland.harvard.edu> - 2017-03-11 05:40 -0800
          Re: Achieving 98% efficiency in a boost converter, RIS-767, new 11-page document Winfield Hill <hill@rowland.harvard.edu> - 2017-03-16 07:55 -0700
  Re: Achieving 98% efficiency in a boost converter, inducement Joerg <news@analogconsultants.com> - 2017-03-16 08:08 -0700
    Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-16 08:54 -0700
      Re: Achieving 98% efficiency in a boost converter, inducement Joerg <news@analogconsultants.com> - 2017-03-16 09:36 -0700
        Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-16 10:42 -0700
          Re: Achieving 98% efficiency in a boost converter, inducement legg <legg@nospam.magma.ca> - 2017-03-19 17:58 -0400
            Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-03-19 15:38 -0700
              Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-03-22 21:49 -0400
              Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-12 11:52 -0400
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-04-12 10:12 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Joerg <news@analogconsultants.com> - 2017-04-12 10:26 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-12 17:24 -0400
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Joerg <news@analogconsultants.com> - 2017-04-13 07:13 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-04-12 10:29 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-12 17:07 -0400
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-04-13 08:22 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-22 16:58 -0400
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-01 15:08 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-05 13:27 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Don Kuenz <g@crcomp.net> - 2017-05-06 05:31 +0000
                Re: Achieving 98% efficiency in a boost converter, RIS-767 dagmargoodboat@yahoo.com - 2017-05-07 14:49 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-08 12:05 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 sea moss <danluster81@gmail.com> - 2017-05-08 18:50 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-08 19:27 -0700
  Re: Achieving 98% efficiency in a boost converter, inducement George Herold <gherold@teachspin.com> - 2017-03-22 19:38 -0700

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