PushPull DC/DC Converter Desing

[adt012]

Hi,

I want to design a high power isolated PushPull converter. Specs are as follows.
V(in): 10-14V
V(out): 120VDC
P(out): 600W
Eff: >85%

I need some material for reading. Is it possible to achieve ZVS for push-pull converter ? What is current feed inverter?
Which PWM controller should is use? What type of feedback is required? How to protect the converter from short circuit?

Regards

 

[Easy peasy]

Really - you ought to do a lot of reading on power electronics - to answer your questions fully enough requires a book length reply ...

 

[treez]

here is my free smps course

SMPS Course _B.zip

drive.google.com

do you actually need the isolation?
Did you decide the topology or was it given to you in a spec?

--- Updated May 17, 2021 ---

There is a folder on push-pull...you could adapt the LTspice sim there to your spec....LTspice is a free download.

--- Updated May 17, 2021 ---

Since you are a beginner, i would get it simulated first....there is a rule in SMPS ....if it works in the sim, it doesnt necessarily mean much....but if you cant get a representative sim running, then your converter will never work on the bench.
BTW, you have >50A of input current and routing/dealing with that will be interesting.

Maybe you could do several converters in parallel.
And of course, the holy word must be said to you...Vicor modules from vicorpower.com
You will likely find that they flog what you want off the shelf.....either one module, or via several in parallel.

--- Updated May 17, 2021 ---

OK, you are asking about "current fed"....so what is your application?....because it sounds like you need something perhaps special.
Is it a power supply to one of those current fed BLDC's?

 

[adt012]

Thanks for reply,

I want to make a low cost simple DC/DC converter and also need high efficiency. I can use any topology which can handle the required power. I just want to learn how power electronic design works.

Regards

--- Updated May 17, 2021 ---

Thanks for reply,

I want to make a low cost simple DC/DC converter and also need high efficiency. I can use any topology which can handle the required power. I just want to learn how power electronic design works.

Regards

I need isolation because i want to work with TL431 with opto coupler plus the loop stabilization stuff.

 

[BradtheRad]

I want to make a low cost simple DC/DC converter

Here's a boost converter. Simple, low cost, low power. A basic construct to build from. It may not be the exact topology you finally build your project with, nevertheless it demonstrates principles of DC-to-DC SMPS operation.

The bright white led's each need about 3.5 V in order to light. The pots are adjusted to boost the 5V supply to great enough voltage.

 

[Easy peasy]

@BradtheRad, for 10V to 120V ( likely he will want 150V for an 110Vac inverter ) a cascaded boost would be the better option, gate drive the same, lower voltage FET and diode for the 1st stage, higher for the 2nd stage, the Duty cycle will then be not as problematic as that needed for 10V to 120V that a single stage would need.

 

[treez]

I need isolation because i want to work with TL431 with opto coupler plus the loop stabilization stuff.

OK, but as you know, you could, if you wanted, use TL431/opto with non isolated designs.

 

[adt012]

Thanks for reply.

I want to ask some very basic question.
1) How to choose the DC input cable thickness?
2) How to choose Fuse current/voltage rating at the input side?
Vin = 10-14V
I max = 60-75A
3) Is it possible to have reverse polarity protection at input side?

Regards

 

[KlausST]

Hi,

1) I guess every cable manufacturer will have online tables with these informations. And many other sources will provide the same informations, too.
In detail it depends on your country, cable type, climatic environment, additional cabling aside...

2) every manufacturer and every fuse datasheet should provide this information.
You need to look for "hold current" to meet your specifications.

3) Yes. Do you have a more detailed question on this?

Please do an internet search on your own, before you ask here.
If you already did, please show your search phrase. Then we can help you to refine your search phrase.
If the results did not provide the asked informations, please give links to the documents, then we can help you how to interprete the datasheet informations.

Klaus

 

[BradtheRad]

1) How to choose the DC input cable thickness?

Ampacity tables:

amasci.com/tesla/wire1.html

www.powerstream.com/Wire_Size.htm