How to convert high-voltage DC-DC power?

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Majidf0

Joined Sep 30, 2022
3
I am currently designing a power conversion system for an EV. The system must power a number of electronic devices all running at around 12V, this is where my issues begin.

The accumulator system thats being used operates at around 230VDC. I must step this voltage down to 12V, but have found it to be a far more difficult task than intended. There aren't any DC-DC Converters out there that perform such a large step-down, so I've been looking into other methods, including the use of a 48V-12V converter and using a resistor network to stepdown the voltage so the DC-DC can use it effectively. Im not looking at a massive power conversion here, I only need around 250W of power for the electronics im powering. Any help or insight into this would be greatly appreciated. I would like to note that I must use the accumulators to power the GLV electronics, therefore I must use a converter of some sort.
 

nsaspook

Joined Aug 27, 2009
13,079
Normally you would buffer the LV output with a battery. So a solar charge controller designed for a HV input string voltage to battery bank might be a good ref design.
 

Ian0

Joined Aug 7, 2020
9,667
Would it be possible to hack a universal ATX supply by bypassing the diode bridge or even just leaving it?
It is most likely that it will work simply by connecting 230V DC to L and N. There are two provisos:
1. The DC input will only use two diodes of the bridge rectifier. The bridge rectifier may have been specified so close to the limit that it will fail if the power is not spread over all four diodes; but it's unlikely.
2. If there is a PFC front end, it may need AC for it to work correctly; but it's unlikely.
I've used small AC/DC converters on DC and they have worked with no problems.
 
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