[RE-wrenches] P1 micro performance

[Bill Loesch]

Hi boB,

Kudos to you, too. Flat-topping (bottoming) is so very descriptive and 
hopefully universally understandable. Excellent analogies.
Technical education/expertise sharing is one of the most prized benefits 
of belonging/participating on the RE-wrenches list.
Thanks,

Bill Loesch
Solar 1 - Saint Louis Solar
314 631 1094

On 22-Mar-13 1:07 AM, boB wrote:
> On 3/21/2013 9:59 PM, Exeltech wrote:
>> Wrenches,
>>
>> I'm probably a lone voice on this .. and not intending to get overly 
>> picky.
>>
>
>
> No, two lonely voices, Dan.
>
> I associate clipping with audio waveforms which stops
> the negative or positive voltage peaks flat.  Also called
> flat-topping.
>
> Limiting is like turning down the volume.  The waveform
> stays the same and does not distort as it would if it
> were being flat topped (and flat bottomed)
>
> Thanks !
> boB
>
>
>
>
>>
>> Could we call power limiting what it is .. "limiting", and not 
>> "clipping"?
>>
>> Clipping implies distortion, which isn't the case here. Limiting is 
>> just that.
>> The inverter output is limited to some maximum value -- not "clipped".
>>
>> The output power curve flattens when integrated over time, but this 
>> still isn't
>> distortion in the waveform.  It's simply a point in the output where 
>> the derivative
>> is zero.  Not increasing, not decreasing.  Just .. zero.  No 
>> additional increase
>> in the output for an increase in available energy at the input.  
>> Think "governor"
>> on an engine....
>>
>> Thanks.
>>
>>
>> Dan Lepinski, Sr. Engineer
>> Exeltech / Exeltech Solar Products
>>
>>
>> --- On *Thu, 3/21/13, David Brearley 
>> /<david.brearley at solarprofessional.com>/* wrote:
>>
>>
>>     From: David Brearley <david.brearley at solarprofessional.com>
>>     Subject: Re: [RE-wrenches] P1 micro performance
>>     To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>>     Date: Thursday, March 21, 2013, 11:37 PM
>>
>>     Thanks for sharing the screen capture, Marco.
>>
>>     Interesting issues to think about here. This is actually prime
>>     clipping season in many places (not sure about Hawaii) due to the
>>     cool weather. While there are more sun-hours in the summer, the
>>     cell temperatures are often high enough that you won't tend to
>>     see rated power out of the modules.
>>
>>     While I'm not running performance models for work, the people who
>>     do are routinely increasing dc-to-ac ratios, often as high as
>>     1.4-to-1. Having said that, most inverters aren't installed on a
>>     roof. (Not yet anyway.)
>>
>>     I'd probably lean to a more conservative sizing ratio for micros.
>>     While I can imagine some scenarios where I'd be comfortable with
>>     a 215 W micro on a 265 W module---like a flat roof install in
>>     Vermont, which reportedly doesn't see 1,000 W/m^2 very often---I
>>     wouldn't try that here in Texas.
>>
>>
>>
>>
>
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
> Version: 2013.0.2904 / Virus Database: 2641/6187 - Release Date: 03/18/13
>




-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.2904 / Virus Database: 2641/6187 - Release Date: 03/18/13
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20130322/25fc5e2a/attachment-0004.html>