If the object of the crowbar is to limit the voltage from reaching Voc, ...
Nope, the voltage regulator is to draw enough current to keep the open circuit voltage under 600V.
The crowbar is to short the array if the current exceeds what the VR can handle. If the design is good, the only time the crowbar would operate is if the sun was high and inverter stopped drawing current.
... You would have better luck crowbarring one or two panels in the string until the operating voltage of the remainder of the string went low enough that adding those panels back into the string would be safe. ...
Great idea. Smaller transistors and heatsinks. Just have to sense the output voltage and switch a few panels in and out as the sun came up (or went down). I wouldn't use the term "crowbar" since that carries connotation of latching. Just be a 10A switching circuit, on or off.
... You still have the problem of what to power the crowbar circuit from. ...
If the sun is up you have power. There will be an amp or two through the module. Gin up a current source power supply - like in a 4-20ma transmitter.
For my part, this is all fluff and dung - I don't see the mfg changing for a small market. And my first order guess is maybe there is a $1000 at the retail end available.
And there is one other issue - I know very little about PV. I am mostly enjoying listening and applying some what-if's drawing from the basic physics that I do know
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