600/800W 220~230v AC Inverter SMPS from 12v DC

[cicelywu]

for high effectivity transformer, first we should be select low loss core, e.g. TDK PC95 core, from 25°C to 120°C，testing power loss at 100 kHz, 200 mT，power loss is 350 kW/m³，it is less than other material(e.g. PC44), seocnd we should be select reasonable configuration, e.g. wound using Sandwich metthod, for reduce leakage inductance ,meanwhile try to reduce capacity, other we select reasonable wire diameter, o\sometime we use litze wire, to deduce skin effect and proximity effect.
of course we should be consider price when we design parts.we design a transformer from theory first, we must verity the design from practical operation, and adjust and optimize the design, meanwhile design parts can be made mass products.

 

[rezacadet]

Hi Tahmid,

As you r in Dhaka & you are working on it, Can you please tell me is "Ferrite core" for any kind of HF Transformer available in Bangladesh Market ?
And if yes then from where i can manage it ? By the way which part of Dhaka you stay. I am from Badda.

BR
Reza

 

[szhighstar]

Hi Reza, if you need magnetics part support, e.g. ferrite core and bobbin and other raw material and transformer, I can help you.

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Hi Reza, if you need magnetics part support, e.g. ferrite core and bobbin and other raw material and transformer, I can help you.

 

[Tahmid]

Lots of different types are now available. Check in Stadium Market and Patuatoly.

 

[szhighstar]

sorry , I am in China, I send some data of core to you for reference, if you need ferrite core or data (Mn-Zn and Ni-Zn, power core and high permeability core) and powder core and metal type of core, I can help.

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sorry, I do not know how to send pdf file

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send again, I design transformer, however I ofteruse these raw matrials, it maybe can help you.

 

[sam781]

Lots of different types are now available. Check in Stadium Market and Patuatoly.

Dear Brother,
I want to make dc-dc converter having power handling capability of 500W at 50kHz frequency. Which core should I use? Mention some shop name in Dhaka where my desired core is available.

 

[szhighstar]

Ee55/etd49/p42/u67

 

[sam781]

@rezacadet: Did you get Ferrite core? If yes, please mention shop name.

 

[Tahmid]

You don't need to go to one particular shop. If you just go to Stadium Market or Patuatoli and ask them for ferrite core, you'll find plenty of shops selling ferrite cores.

 

[sam781]

I went and ask some shops in stadium market and in Patuatuli but they do not sell Ferrite core.
I found a shop in patuatuli who sells ferrite core but the core is very small (1"-1.5"). There is no product number and brand label for the cores. It would be very helpful If you could refer shop where I can get larger core (around 500W).

 

[Tahmid]

You should check "Dhaka Electronics" in Patuatali. They sell a wide variety of ferrite cores. It is also available in other shops in Patuatali. Instead of asking them for "ferrite core", ask them for "chopper". Then, they can show you the larger cores.

Hope this helps.
Tahmid.

 

[picgak]

Hi Reza Sam781,
I would like to join your discussion of a new smps. did you get ferrite core. once you get it we can fix the max operating freq allowable to that core be sure it can handle 800w.
regards ani

 

[sam781]

@Tahmid: Some days ago I went patuatuli. I got ETD44 ferrite core in Dhaka Electronics but there is no product code/number. So, I didn't buy that. It has become very hard to get a ferrite code with spec here in Dhaka. It would be very helpful if you could refer another shop having ferrite core with proper product number.

@picgak: Thank you very much to come here to help us learning SMPS design. I'm trying to manage required ferrite core with the help of Tahmid. Once I get it, I'll let you know. I've a old core (most probably ETD34) without product number. Can we start with this?

 

[Tahmid]

I doubt you're going to find any specification or any further information. At Patuatali, they sell the ferrite cores without any product code or information. So, you'll have to make do with estimates and experimental figures.

 

[sam781]

@Tahmid & picgak: Can we start with already available ETD34 (no spec) core? Could you please suggest how to find out power handling capability of this core?

 

[picgak]

Hi sam781,
The specs for your ETD34 is attached below.
regards ani

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[sam781]

Thanks a lot picgak
But I don't know the grade of my core. There are 6 grades in the datasheets. The core was extracted from a old circuit board (probably PC power supply).

 

[walkura]

@Sam781,

if You have access to an inductance meter You can put a couple of windings on the core and measure the inductance.
Then You are able to find the Al value, (and this way You are closer to identifying your core material)
You can find a simple calculator to find the Al value on this site.
**broken link removed**

About your inverter,
have a look at this application note.
(and please, do not try to build this before You got some experience with building switch mode supply's)
**broken link removed**
Take it apart in functional blocks and try to get a feel for them before You start the whole thing together.

The first step should be the DC-DC converter and the magnetic's involved,
if You have that working well then You can start thinking of an inverter.
My advise start with a dc-dc converter from low voltage to low power & voltage,
this way You can experiment and mistakes don't (have to) end with a big bang.
It is better to build a trial for learning purposes, then to try an 800 watt as your first switch mode supply.

Good luck and be carefull.

 

[sam781]

if You have access to an inductance meter You can put a couple of windings on the core and measure the inductance.
Then You are able to find the Al value, (and this way You are closer to identifying your core material)

Sorry, I do not have access to an inductance meter right now.
Is there any other alternative way to calculate inductance?

The first step should be the DC-DC converter and the magnetic's involved,
if You have that working well then You can start thinking of an inverter.
My advise start with a dc-dc converter from low voltage to low power & voltage,
this way You can experiment and mistakes don't (have to) end with a big bang.
It is better to build a trial for learning purposes, then to try an 800 watt as your first switch mode supply.

Okay. I'll make a dc-dc (12v->325v) converter first. As I do not have datasheet of the core, what should be the good approximation of power handling capability of it?

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As per the output power table (for Half or FullBridge Topology) of Ferroxcube-Philips referred by goldsmith, ETD34 core can handle 255w at 48kHz and 510w at 96kHz. Can I assume my ETD34 core having this power handling capability to start?

https://www.edaboard.com/threads/229615/#post1100003

 

[walkura]

To be honest I am not sure, when i looked it up i found a page which claims 170 Watt for an ETD34 at 100 kHz.
But knowing Goldsmith's expertize in this subject a little, I would put some faith in his words.

But what i meant to say yesterday, if this is your first switch mode supply then it is a good idea to build a trial first.
Low power in-low power and voltage out, just to get a good understanding on the oscillator, feedback, calculating your transformer, waveforms, etc. etc. and all the difficulty's that come with it.
If You try to build an supply that should have 325 Volts of output voltage, it is very likely that a simple oscillation might destroy your mosfet or output diodes before You can blink with your eyes.

It is a safer approach to start with let's say from 12 to 24 Volt, You can later always recycle the components and your core, but it might buy You the time to switch it of before it burns up.

Good luck.