[RE-wrenches] Efficiency Curves of Fronius Inverters?

[Wind-sun.com]

Efficiency Curves of Fronius Inverters?Some of the early (circa 2000'ish) grid tie inverters (not just Fronius) had problems tracking MPPT at the lower 10-15% or so of the input voltage range.  Not sure if that is related to the experience you had with that IG4000 or not.

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Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
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  ----- Original Message ----- 
  From: Peter Parrish 
  To: 'RE-wrenches' 
  Sent: Thursday, July 09, 2009 8:18 AM
  Subject: Re: [RE-wrenches] Efficiency Curves of Fronius Inverters?


  I have a decidedly skeptical opinion of the Fronius MPP algorithm. A few years ago, I was one of the first (I believe) to notice a curious "continuous saw tooth ramping" of the DC current and voltage on a couple of Fronius IG4000's. The problem (I was told by Fronius) was triggered by an increasing Vdc crossing 240 V (the "line voltage"). The problem was fixed by a SW upgrade. Ignoring the fact that 240 Vac is not a fixed value, the standard Fronius IG inverter line may have a generic challenge when Vmp is in the 240 V range. Was this the case?



  - Peter



  Peter T. Parrish, Ph.D., President
  California Solar Engineering, Inc.
  820 Cynthia Ave., Los Angeles, CA 90065
  CA Lic. 854779, NABCEP Cert. 031806-26
  peter.parrish at calsolareng.com  
  Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885                                                                                                   



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