[RE-wrenches] Fronius Problem

[Mark Byington]

"A Fronius IG 4000 is doing some weird cycling. Every 45 seconds the voltage
pops up to Voc and drops back to Vmp immediately followed by a downward ramp
of voltage and corresponding rise in current. This repeats continuously."

We had this symptom on about 20% of our Fronius systems, years ago.  The
operating point would ramp up to maximum power, then quickly drop down to
about 60% of power, then slowly ramp back up, etc, with a 45 sec
periodicity.  It seemed to be worst when the DC operating voltage of the
array is close to the AC line voltage.  Discussed with Fronius; no
resolution.  We tend to not use Fronius any more due to this issue.

Mark Byington
Cobalt Power Systems