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I am designing a product for utility scale solar panel systems that operates at a maximum of 1500 V DC per circuit. For convenience, I'd like to power some electronics by tapping into the 1500 V DC. If I can get down to ~15 V DC that would be most desirable. The load requirement is about 1 A.

Ideally I would have a battery in the system to smooth things out. I know somebody just twitched when they saw battery. But if it makes things easier the battery can be an intermittent load to the 1500 V DC supply, while the electronics are continuously powered from the battery via a regulator.

It does not have to be efficient, cost is more important. Is there a simple circuit to do that?

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    \$\begingroup\$ Personally, since you already have solar panels, I would add another small solar panel just to generate the low voltage. \$\endgroup\$ Apr 18 at 21:17
  • \$\begingroup\$ Sounds like you need a small flyback converter. The 1.5kV makes the design somewhat more difficult in terms of semiconductors to work at that voltage and the insulation requirements. \$\endgroup\$
    – Kartman
    Apr 19 at 2:13
  • \$\begingroup\$ Moreover, the isolation requirements between your PV string and your 15 V usage is going to be tricky. If you absolutely have to make it happen, I would contemplate putting a low voltage Zener diode in series with the string, rated to more than your max short circuit current, and step up and isolate from there. \$\endgroup\$
    – winny
    Apr 19 at 6:49
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    \$\begingroup\$ @DavideAndrea yes this is what I'd normally do but in this case it throws off system cost because the mounting system for smaller inexpensive panels doesn't fit this system. \$\endgroup\$ Apr 19 at 19:56
  • \$\begingroup\$ @Kartman this is what I was getting toward, thanks for putting a name on it, I finally found some products for this purpose specifically. \$\endgroup\$ Apr 19 at 19:59

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This isn't a good idea, because your circuit is still in series with the rest of the solar panels, it will have to be able to handle 1500VDC across the circuit. In addition you could wear out the panel due to uneven loading of current. In addition the load will mess with the MPPT and the overall efficiency of the string.

If you do decide to go through with it, use an isolated supply that can handle up to 1500VDC across it.

A better thing would be to pull power from the MPPT or from the grid.

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  • \$\begingroup\$ There are some products built specifically for this application, as I have come to find out. The major distributors carry it, product link but is it still risky? \$\endgroup\$ Apr 19 at 20:05
  • \$\begingroup\$ Just make sure it doesn't interfere with your string efficiency or MPPT, You could plug it in and see if it drops the efficiency if you can monitor the output. \$\endgroup\$
    – Voltage Spike
    Apr 19 at 21:21

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