Questions on Inverter and Tranformer desgn

[babinton]

Hi everyone,
I have build simple square wave inverter using off the shelf transformer, now I am interested in moving to more proffessional design area. However, I have to gain some valuabel knowledge first which I know I can get from you people.

First. The design of a high frequency transformer.
I have a transformer I removed from the power pack of a Computer system and I would like to use it for designing a high frequency transformer which I can use in the DC-DC converter stage of my inverter cct. What I want to know is : is the transformer suitable for what I have in mind? if so, how do I go about rewinding it i.e. what will be the primary winding area, current rating, no of turns and also the same question goes for the secondary side for an application using 12V DC input and the converted DC output is 48 V DC for a power rating of 400W( also, if I want to scale the power upward to 1500w, how do I go about doing it).

Second Question

I have a power transformer I removed from a 1000VA regulator. Can I use this transformer for 1500w inverter. How do I calculate the winding parameters for the winding( such as wire guage, current ratings, wire area, current density, winding ratio) for both the primary and the secondary. Also, I want an extra 12V winding on the transformer so that I can charge the supply battery when there is main supply. How do I go about the desing.
The transformer dimensions are
length = 110mm
widht = 95.7mm
and thickness of pile = 50.6mm

finally,
I want to build a filter to filter the pwm output , however I don't know how to select the inductor core and winding to use.( I would appreciate if a book on practical tranformer design can be upload.) I have an inductor I also removed from the same power pack. It is a toroidal inductor with diameter of about 4cm. Can I use this to filter the ouput of a 1500w transformer.

Note: I have already gone through all the post on inverter in this forum, but I still need more help that is why I am sending this post.
I will greatly appreciate your help.

Please. If you have any material on the questions I asked above, I will be glad to receive a mail with the materials attached(my email is : faruq.bello@yahoo.com or ruksy02@yahoo.com).
Thanks

 

[babinton]

Hi, I post some questions and nobody has responded, from the number of views I can see that some people are interested. Please, reply because I will be very glad of any help I can get. Regards

 

[Johansen]

There are no practical transformer design books for what you are looking to build.
Very few people have even attempted to start.

The transformer you gave the dimensions of is more appropriate for a 700-900 VA or a 500Watt inverter.
(assuming 60Hz)

You can match and even exceed the energy density found in computer power supplies because you are not limited to safety regulations that limit fill factor.

Goodle magnetics design, there are hundreds of pdfs to help you calculate that kind of stuff.

It is impossible to provide wire gauge, turns, actual size etc. I suggest you start reading.

for your 12VDC to 48VDC converter I suggest you build a full bridge inverter & a transformer constructed from 4-6 E cores from identical PSUs.
simply scaling it up works well, but some issues ignored become dominant. for example dimensional resonance is just one.

A 4 cm core tells me nothing about its magnetic qualities. Assuming you want to PWM the transformer you can put the filters before and after, before, or after the transformer.

Everything is a compromise.

 

[babinton]

To Johansen: Thanks for you reply and more questions

Hi johansen,
Thanks for replying to my question I appreciate that, in my country the transformer we use operate at 50Hz so probably the dimension I gave correspond to that of a 1000w power transformer, I am not saying you are wrong just that I am just getting into transformer design and I don't know much about it, hence I am trying to get as much info as possible on the topic.

About the transformer from the PSU of the system, what I want to know is: is it a ferrite core transformer, if so how do I go about using the little info I have on the transformer to design for what I want i.e. I want it to operate at 25KHz with input voltage of 12V an output voltage of 48-72V with power output of between 200-300W.

Sorry, I might not be making much sense but please bear with me, I am just a beginner and please can u give me links to the site you mentioned.

 

[FvM]

A power transformer according to the core dimensions you gave, would achieve a 50 Hz continuous rating of 250 to 350 VA at maximum, depending on specified temperature, but I can't imagine a value above 400 VA.

 

[muralicrl]

Hi,

Whatever material I am having hereby I am sending, it may be useful to you.
See the attachment.