Hello everyone,
I am working on a tethered drone power supply. a long wire with 400v will be attached to the drone and I need to turn that into 24v @60A 125max. Yes I know that is a crazy about of voltage and current. I have found some ~3000$ options out there but they are for charging electric cards and are very heavy. I am sure I can make a lighter for less money and more redundant. The Drone is 10 gram/watt, so if I can save 10 grams, I can get away with one more watt of waste heat. also, because it will be mounted to a drone, I can vent heat easily.
1st idea: Using the amazing power supply designer at
https://webench.ti.com/power-designer/ is spat out a very nice
UCC28951QPWRQ1 Phase-Shifted Full-Bridge circuit but it looks like I would need to make/order custom inductors and transformers for it. it also doesn't show me the current needs for those transformers, so I would need to work that out as well. There are some other issues with the design it shows me, such as, it cant find FETs that can handle the current and Voltages... I can fond some on Digikey. I am also worried that if it is using ideaFETs in its calculations the other component values might be off. I can also not simulate this design in webench. So with all these issues I was thinking of just designing my own.
Has anyone here make a similar design using the UCC28951 based circuit from webench? or can offer any ideas for sourcing/making those transformers?2nd idea, I would like to use a couple Current-Mode PWM Controllers working at a high frequency to allow for smaller transformers. if I can get maybe 6 of them to work together each would only need to output around 20A. This would give it good redundancy. and allow for easier testing. I was thinking of a MAX5071A?
Does anyone have a suggestion on PWM controller chip that would be good for this application? or even a better idea for circuit topology?Side note: The tether will be around 150m long. It is basically a transmission line at that point and I am hoping that a get away with just using a 2mF. yes I know a ~500v 2mF cap is a lot. I dont know what the transient current needs of the drone will be until we start testing.
More Side Notes: this will be directly attached to the backup batteries on the drone. This will help smooth out any voltage drops and act as a backup. I was thinking of adding a UPS, but that would add too much weight and from my testing the batteries handle everything just fine without.
Transformer info:
Ns1toNp = 1, Ns2toNp = 1, Lp = 1.3 mH
Ns1toNp = 105.49 m, Ns2toNp = 105.49 m, Lp = 288.38 µH
Ns1toNp = 100, Lp = 20 mH, Leakage_L = 20 µH
Looking forward to hearing everyone's thoughts.