# 12kW power supply spec with vin = 1000v to 880v?

1. ## 12kW power supply spec with vin = 1000v to 880v?

Hi
A way of doing this Power supply spec?…..

Vin = 1000v to 880v (source is 1000V but cable resistance between source and Power supply is 7.5 Ohms so actual vin drops with load)
Vout = 48V
Pout total = 12kW
Efficiency 0.85
Pin total = 14100W

Chosen Topology = In blocks of three Two Transistor forward converters with inputs stacked and fed from three “totem pole” series capacitors.
7 totem poles altogether. (ie 21 x 670W two transistor forwards).

All outputs paralleled.
12 Amp Current clamps on output of each two transistor forward so none hog the current.
Do you see any problems with this?

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2. ## Re: 12kW power supply spec with vin = 1000v to 880v?

We would do this with 3 x H-bridges in series, 600V devices on each - giving 1800V input max

84A o/p per H bridge @ 48VDC ...

Automatic input voltage sharing due to topology and control design, series resonant converter, fixed freq, 75kHz.

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3. ## Re: 12kW power supply spec with vin = 1000v to 880v?

Thanks...Woops yes, I forgot to include an error amplifier which would kick in if Vin to any converter fell to 250V, and it would start pegging back its output as the vin fell to 250V and lower….so as to allow redundant units to come back in and stop their input capacitor over charging.

..Also would have a micro on the output of each converter to measure output current, then do “drooping”, ie dynamically change the Vout error amplifier reference so that from zero load to full load, Vout would go from 50V to 48V…this to encourage sharing, (as Easy Peasy has previously kindly described albeit in a very different situation).

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4. ## Re: 12kW power supply spec with vin = 1000v to 880v?

It seems ,the output voltage is very low but constant.

You can go for 12 No of 1kW half bridge LLC(Output current 21A @ 48V) connected in parallel. You can increase the overall system efficiency.

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