How to connect multiple power suplies outputs in parallel

[obiwan]

Hello !
I guess how many SMPS could be tied together to obtain high currents, e.g: 24 V @ 12 kW from several 1 kW devices, to a single resistive load. Could this be possible ? How to equalize the several individual power supplies ? Is there a simple method ?

Thank you.

Obiwan

 

[Kanwar]

You can connect them using low ohmic value current sharing resistors such as 0.05ohm 5W each

 

[obiwan]

Thank you Kanwar.
In my case, I need to parallel about 10 units 24V 50A (1200 W) SMPS to form one single 12kW. Please forgive my ignorance but where can I get these kind of resistors ? I mean that just the connection cables could have this resistance value ...

On the other hand, what happens with the voltage regulation in this case ? Connected in parallel, could each power supply understand which is the value of the output voltage to be mantained at the output ??

Thank you in advance for your help.

 

[dzwer]

http://www.meanwell.com/search/rsp-1500/rsp-1500-spec.pdf
On the last page.
Also see other models from MW.
In your case do not put resistors if your supplies are not designed for parallel work. Just adjust every output to one value at load 1-10A.

 

[Kanwar]

Is there any sync option in your supplies, you need to connect the resistors at outputs in order to force current sharing.

 

[obiwan]

Thank you dzwer and Kanwar. What I need is the real theory of operation or design. Not just a ready made power supply. I am building these power supplies myself but I have this problem in mind and need a scientific reply for equalizing the output. Please consider that in the absence of an output diode, any mismatch between outputs will make current to flow between the several power supplies. Thank you in advance for your cooperation.

 

[dzwer]

https://ps-ssl.de/regiamea.de/ablage/dn-62.pdf
Read this comparison between current mode control and voltage mode control SMPSs.
If you use voltage mode control - maybe it is better solution to think about current mode control(CMC).
Here is the theory:
http://www.national.com/assets/en/other/UnderstandingandApplyingCurrent-ModeControlTheoryv1.pdf
http://www.venable.biz/tp-05.pdf
... and many more documents
Some CMC controllers have the ability to work synchronous for the best current sharing method, like UC3846 controller.

 

[lillian]

hello my friend i have been trying to build an inverter for the past year now but having great problems could u assit me in this. Thank u