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Your capacitor choice is key to solar photovoltaic (PV) array economics

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NimrodO0l1
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re: Your capacitor choice is key to solar photovoltaic (PV) array economics
NimrodO0l1   8/26/2011 9:17:11 PM
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Seems to me that the solution is to make the capacitors be a field-replaceable unit perhaps with monitoring circuitry to help identify likely failure. I think eventually that some version of smart-grid might come into play including perhaps the inverter communicating over wireless to a household (commercial facility?) command and control center. Umm, what is the failure mode when the capacitor shorts?

HRConsult
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re: Your capacitor choice is key to solar photovoltaic (PV) array economics
HRConsult   6/18/2011 6:03:17 PM
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I am in favor of any improvement in inverter lifetime. The thought of eliminating electrolytic capacitors certainly has great appeal, and the fact that you have done so, is great. I was doing fine until I got to the part where you say "...the film capacitor offers 30,000 hours with characteristics (for example, self-healing dielectrics) that make it very likely that it will continue to operate well beyond that figure." It is still quite a stretch to get from a 30,000 hour life specification to a 200,000 hours operational life. Not only that, but since you are using four caps, you need to have all four exceed their specified life by a factor of seven. Your expectation is based upon the assumption that dielectric self healing will get you there. My experience with film caps is that, although self healing does extend life, each time there is a breakdown, damage occurs to the capacitor that is cumulative, and eventually, the capacitor shorts. It is also unknown how many the capacitor broke down and healed itself to get to 30,000 hours. If the ultimate failure mechanism is partial discharge, then the self healing dielectric characteristics of the capacitor will not come into play at all. It is not clear to me that you have a solid engineering basis for extrapolating the specification sheet life characteristics to your needed operational life. I think that you approach makes some good progress in the area of reliability improvement in microinverter life, but I remain unconvinced that it is the final solution.

stradcar
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re: Your capacitor choice is key to solar photovoltaic (PV) array economics
stradcar   6/2/2011 2:20:11 AM
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If I could only get my hand on this product in jamaica.Ah boy adrian.levy@jamtechenergy.com any day

Kevin.Jackson
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re: Your capacitor choice is key to solar photovoltaic (PV) array economics
Kevin.Jackson   5/18/2011 1:38:04 PM
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Great!

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