30vac to 30vdc converter

[raycenteno]

Hello,
I am working on a project that requires dc volts. Currently my power supply generator is 30vac @ 32 amps. I would like to know if there is a way that I can transform the 30vac to 30vdc and keep the 32amp range. I would appreciate the help from anyone that can offer it.
PS. I have not worked with circuits since i was in junior high school (very long time ago), I suppose that once I can refresh my memory, it should get easier.

 

[Alun]

To do this with this efficiency you'll need to build a switch mode power supply which will be noisy and they're not the easiest things to build either, what do you wish to power with your power supply?

 

[ante1]

Hi raycenteno,

Welcome to our forum.

It’s not possible to put in 960W AC and get 960W DC at the other end!

 

[Alun]

Ante,
You're right but we can get to 90% efficiency these days without too much of a problem, you might put 960W in and get 864W out. ;D

 

[ante1]

Hi Alun,

Well, Ray wanted to keep the 32A on the secondary side and this is not possible unless he settles for a lower voltage!

 

[Alun]

True, there's always some loss in any system.

 

[ante1]

I think even 90% efficiency is a bit optimistic. Just putting a rectifier on a transformer will be a hard one to reach 90%! 8)

 

[Alun]

That's funny I calculated with  a rectifier to be for 30Vin @ 32A:
Vout = 30 * 1.414  - 1.4 = 41.026V
Iout = 32 / 1.414 = 22.627A
Pout = 928.295W
Efficiency = 928.295 / 960 * 100% = 96.697%
This could be improved by using high performance ultra low voltage drop schotky diodes for the rectifier.

If we assume 90% for DC-DC conversion in this example the total efficency will be:
0.96697 * 0.9 *100% = 87.03%

However if you used the best componants money could buy DC-DC is 95% efficent so:
0.96697 * 0.95 *100% = 91.86%

Having said all of this you're right I'd expect about 80% efficiency for this whole circuit using normal cheap and nasty componats. ;D

 

[audioguru2]

Vout = 30 * 1.414

 

[ante1]

Yeah, like I said ” 90% efficiency is a bit optimistic”  ;D

 

[raycenteno]

thanks for the input, i do apologize for placing this question in the projects section. my goal it to have at least 90 volts and 160 amps on the end side of the power equation. I was planning to put together enough psu together in parallel and series to achieve this end volts and amps. I know it is quite a project, but I feel I can accomplish it. My goal is to power a dc motor. The motors data is 72-120vdc 130amps cont 150 amps/hr 500amp peak. I know that once i have completed my psu it should take up an area of 3'x4'. I understand that I will have some losses somewhere, but i am not sure where and how much. I was planning on using 15 psu's, me being optomistic and little experience, i was hoping to get the 90vdc @160amps. I greatly welcome your design, ideas, help, and suggestions. As well as info on what components you guys would recommend for my build, ie capacitors rectifiers and diodes.

 

[audioguru2]

My goal it to have at least 90 volts and 160 amps on the end side of the power equation.

That is 14.4kW! You said your power supply generator is 30vac @ 32 amps, which is only 960W. Will you use more than 15 generators to power it all?