I been looking for an off the shelf power supply that can adjust its output voltage to compensate for losses, in my case in transmission line. Searching on DigiKey, I narrowed down my search to power supplies with remote sense feature. For example EMH250PS18 states "Remote Sense Compensates for 0.5 V total voltage drop", another vendor and model MVPS600-1015 state "Output Adjustability +/-3%". In practice I see it adjusting its output to ~5V over nominal 15V. However, adjusted voltage drifts over time, which worries me that it eventually will drop too low for my device to work. At 15V output 0.5V doesn't give me much in terms of current I can deliver to the load. Ideally, I would have larger cable but for now I have to work with what I have which is 24AWG. Anyhow, does anyone know which of the shelf power supply can adjust its output to say +/-5-10V? Is there other ways to compensate for losses in transmission line? Ideally without building custom board.
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2\$\begingroup\$ Remote sensing is the way, and is never meant to compensate for gross losses (i.e. if you're losing 5-10V between your source and load at 15V on the PSU output, you need to significantly beef up the copper between the source and the load). \$\endgroup\$– Adam LawrenceOct 28, 2021 at 20:49
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2\$\begingroup\$ Thank you Adam. I suspected that maybe the case. 3.5A at 15V over 30m of 24AWG cable isn't ideal. Was hopping there maybe a solution I am not aware of. \$\endgroup\$– semenoffOct 28, 2021 at 20:54
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5\$\begingroup\$ I think 3.5A over #24 wire is excessive at any length. You could start with a much higer voltage (48 V?) to reduce the current, then use a DC-DC converter at the load to reduce the voltage to what the load requires. \$\endgroup\$– Peter BennettOct 28, 2021 at 21:04
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\$\begingroup\$ If you don't have anything but 24 AWG wire, use like five of them in parallel if you absolutely need 3.5 amps--that stuff's way too small for so much current! \$\endgroup\$– HearthOct 29, 2021 at 4:03
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A straightforward way to compensate for transmission losses is to transmit a higher voltage and then put a DCDC step down converter at the far end. The higher voltage means lower transmission losses, and the regulation on the step down converter automatically compensates for any line loses resulting in a constant voltage regardless of load.
Since you only need 15v at relatively low current, you could buy an inexpensive 24v power supply and Buck converter for a few dollars on digikey, Amazon, etc.
answered Oct 29, 2021 at 3:49
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\$\begingroup\$ @semenoff - Yours is a common problem, addressed by Point-of-Load or Point-of-Use converters, which is basically what this answer describes, and is probably a good way to solve your problem. Pumping too much power through those wires wastes energy as heat. Whereas beefing up the copper for such a low transmission voltage would be very expensive, much more expensive than a boost converter at the source and a buck converter at the destination. I suggest 40v at the source. Please accept this answer. \$\endgroup\$ Oct 29, 2021 at 5:15
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\$\begingroup\$ Agree, Buck converter on receiving end and higher voltage is a way to go. I was trying to avoid rework to the device on receiving end but sounds like this is what we have to do. Thank you for your answer and suggestions. \$\endgroup\$– semenoffOct 29, 2021 at 15:07