Hi my friends I need to regulate and control efficiently the battery charge with the output voltage and current than flow from the buck converter, can anyone give me some ideas in order to improve it?.
as you decided to use buck type converter , you then have Vo = D * Vin when D is the duty cycle D=Ton/T , your battery charging voltage is known which will be the Vo and Vin is the input voltage so assume you are charging 12V battery so the datasheet shows the nominal charging voltage is 14.2 and the input voltage is 20Vdc so D= 14.2/20 so every time you measure the output voltage and calculate the duty cycle which controls the buck switches and when you reach the full charging voltage you need to disconnect the battery. Also , there are many algorithms for charging , constant current , constant current constant voltage , choose the proper one for your case.
thanks,
Yasser
How can I have a steady current for battery charging at the buck voltage output?, because if you note the output always is oscillating and it make that the charge change constantly to discharge, is its a big problem than i have, because my batteries are of 24V it make very un steady my sistem.
use lm334 to build a constant current source circuit see the page below
http://www.bristolwatch.com/ccs/
I'm work in in Simscape SimpowerSystem of simulink and my system need 1000 A, i think a BJT transistor is no enough, what do you think?
I read only now the topic.
I can suggest you an obvious solution, if I understand the problem: I think you miss an inductor between the buck converter and your battery. This could avoid the charge-to-discharge oscillation. You can solve this problem first and then you go for current regulation.
It's not easy to provide a 1000A inductor with a convenient inductance value... let's say that is a custom component. You have to ask to a good designer.
It would be great if the buck frequency was high enough to limitate the need of huge inductors!
Hope this helps.
Fausto
Can we talk about it, if you're interested on it?. I'm doing my ph's studies and i need to produce journals, i don't watch troubles in collaborate on one Buck converter for a DC standalone building.
I just read your article ECO-MODEL FOR DC ELECTRICAL SYSTEMS IN STANDALONE BUILDINGS.
Me and my research group are not power electronic designer. We worked in that field, but it's not our first activity.
Other colleagues are instead good designers and if you want I can propose to them the activity.
Did you also consider a split dc dc convertion? I mean: not a single dc-dc buck converter, but several (let's say less than 10) converters in parallel or stand-alone mode.
In parallel connection they could eventually limit and control voltage and max current, be connected in different places of the building and, if well designed, share the same output bus without significant current problems.
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