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

[sam781]

Hi Sam
To prevent such high values , you can increase frequency of operation of this stage up to 200KHZ , as well ! ( because a 630V or 400 V capacitor , with low ESR and low ESL with value of 1uf seems a bit expensive and large )

At this moment I want to use 50kHz. Let's try to do with 50kHz. Anyway, what is the next stage of making 4.26mH inductor. Which type of core (toroidal or ETD) should I chose? How can I chose the required dimension of the core?

BTW : why you have doubt about it ? TS means switching frequency . so 1/50*10^3 =20usec .
so it's true .

:smile:
Thanks...

 

[goldsmith]

At this moment I want to use 50kHz. Let's try to do with 50kHz. Anyway, what is the next stage of making 4.26mH inductor. Which type of core (toroidal or ETD) should I chose? How can I chose the required dimension of the core?

Hi again
As i can remember , i have added some standard tables regarding how to select proper core for our aims . and i think you have seen those tables . isn't it ? if yes you'd better to re look into them !

Good luck
Goldsmith

 

[sam781]

As per the table ETD39 core can handle 467w at 50kHz. Do I need the same core for step up transformer and for filter?

 

[goldsmith]

As per the table ETD39 core can handle 467w at 50kHz. Do I need the same core for step up transformer and for filter?

What do you mean by that ? of course if you select your required core according to that table , you won't have any problem .
Good luck
Goldsmith

 

[sam781]

Dear Goldsmith,

Sorry, I'm not getting your point. I cannot remember any table about filter core selection. :sad:

 

[goldsmith]

Dear Goldsmith,

Sorry, I'm not getting your point. I cannot remember any table about filter core selection.

Hi Sam
Can't you remember really ? those tables in thread of inductor design ??
Ok , go through this thread : https://www.edaboard.com/threads/229615/
( latest pages )
Good luck
Goldsmith
Here is the address :

 

[sam781]

But that table is for transformer core selection. Based on that I chose EDT39 core which can handle 467w at 50kHz when configured at full/half bridge configuration.

 

[goldsmith]

But that table is for transformer core selection. Based on that I chose EDT39 core which can handle 467w at 50kHz when configured at full/half bridge configuration.

The main problem is that you don't know principles of SPWM ! can you remember those literatures that i've wrote for you ? ABOUT spwm ? WHO TOLD IT IS 50 HZ ? who told that you have transformer in out put ?
in out put you just have an inductor ok ? which has low value instead of 50 HZ signal . did you forget what i've told you before ??!!
Good luck
Goldsmith

 

[sam781]

Dear Goldsmith,

Could you please read the following link
https://www.edaboard.com/threads/254847/#post1151287
Where I asked some question about what I was going to do first. Also please check post # 174 where I told I wanted design filter for the first stage (converter stage).

As IRF3205 has anti parallel diode, I do not need anymore diode for freewheeling purposes. Diode having Trr lower is better. Could you suggest some part number which I can use?

For now, I wanted to design filter for the first stage i.e, converter stage. 400-450v 50kHz square wave will be rectified with a bridge rectifier.

Then you wanted to give me two formula in post #175

Humm i think you're referring to the DC voltage increasing stage , well , are you familiar with formulas of an H bridge filter design ? if no , i can give you two formula , one for , out put capacitor and the other one is for inductor .

Then Tahmid referred me a link and you gave me two formula for the filter for converter stage (12v to 450v stage), not for inverter (SPWM) stage.

 

[goldsmith]

Dear Goldsmith,

Could you please read the following link
600/800W 220~230v AC Inverter SMPS from 12v DC
Where I ask some question about what I was going to do first. Also please check post # 174 where I told I wanted design filter for the first stage (converter stage).

As IRF3205 has anti parallel diode, I do not need anymore diode for freewheeling purposes. Diode having Trr lower is better. Could you suggest some part number which I can use?

For now, I wanted to design filter for the first stage i.e, converter stage. 400-450v 50kHz square wave will be rectified with a bridge rectifier.
Then you wanted to give me two formula in post #175
Humm i think you're referring to the DC voltage increasing stage , well , are you familiar with formulas of an H bridge filter design ? if no , i can give you two formula , one for , out put capacitor and the other one is for inductor .
Then Tahmid referred me a link and you gave me two formula for the filter for converter stage (12v to 450v stage), not for inverter (SPWM) stage.

Hi Sam
I'm a bit confused . what is your question now ? and what is the advantage of referring to that page ?

 

[sam781]

How to chose ferrite core for filter? You referred some page with table to chose core for the transformer. Could you please refer any link to chose ferrite core to make filter inductor of inductance 4.24mH

 

[goldsmith]

How to chose ferrite core for filter? You referred some page with table to chose core for the transformer. Could you please refer any link to chose ferrite core to make filter inductor of inductance 4.24mH

It is the same ! i'm selecting my cores for filters according to that table too ! but not for any applications ! here because your out put signal is AC , hence you can use that table too .
Good luck
Goldsmith

 

[sam781]

It is the same ! i'm selecting my cores for filters according to that table too ! but not for any applications ! here because your out put signal is AC , hence you can use that table too .
Good luck
Goldsmith

So, my question is -
As per the table ETD39 core can handle 467w at 50kHz. I chose this core to make converter (12v to 450v) to make 300w inverter in this thread. Do I need the same ETD39 core for step up transformer and for filter for the same power?

 

[electro13]

Hi goldsmith,

im designing a DC to AC inverter and i need help, my input is 12v DC and i want 220v AC, im using a push-pull topology for the first stage, to get the 12v DV to 300, and then using a H bridge to get AC, the problem is that in the first stage i can't get 300v, im using 200KHz PWM, and a ferrite transformer, i think the problem might be the transformer specs, im not sure, or should i use H-Bridge instead of the push-pull, and also at the output how can i get a 220v AC sine wave?

thanks,

electro13

 

[sam781]

I've made MOSFET bridge for converter using four IRF3205. Output is okay. Now next tasks are -
1. Complete winding of selected ETD39 core for the step up transformer (for power 300w)
2. Make bridge rectifier. (Fast recovery Diode required)
3. Make Filter (L=4.26mH, C=1.15uF)
4. Bridge circuit for sine wave inverter from 450v DC to 230vAC (High voltage, low current). 3-4A current should be okay.

Now I've some observation and queries -
1. For rectifier, I found two diode MUR1560 and MUR3060 having the same price (BDT90). Didn't find any other diode of MUR series. I do not need such high current like . So, could you please suggest any other diode applicable here and available in BD market?

2. Still unclear about choosing ferrite core. I was unable to make clear my requirement to Goldsmith :sad:. Filter is for making pure dc from the rectifier output to be used as input for the inverter stage.

3. From another thread I found a suggestion to use IRFP460 (500v, 20A, 0.27ohm) for inverter stage. It costs BDT150. I found IRFP450 (500v, 14A, 0.31ohm) which costs lower than BDT100. For my application doesn't require such high current. I think IRFP450 should be okay. Please let me know if there is nay other drawback of this. Also suggest any available effective alternative MOSFET.

 

[Tahmid]

Now I've some observation and queries -
1. For rectifier, I found two diode MUR1560 and MUR3060 having the same price (BDT90). Didn't find any other diode of MUR series. I do not need such high current like . So, could you please suggest any other diode applicable here and available in BD market?

2. Still unclear about choosing ferrite core. I was unable to make clear my requirement to Goldsmith :sad:. Filter is for making pure dc from the rectifier output to be used as input for the inverter stage.

3. From another thread I found a suggestion to use IRFP460 (500v, 20A, 0.27ohm) for inverter stage. It costs BDT150. I found IRFP450 (500v, 14A, 0.31ohm) which costs lower than BDT100. For my application doesn't require such high current. I think IRFP450 should be okay. Please let me know if there is nay other drawback of this. Also suggest any available effective alternative MOSFET.

1. Look some more. You should be able to find MUR4XX and MUR8XX.

3. You can get IRF840 for around BDT 50. You can find a whole bunch of 500V MOSFETs available at different ratings.

 

[goldsmith]

Hi goldsmith,

im designing a DC to AC inverter and i need help, my input is 12v DC and i want 220v AC, im using a push-pull topology for the first stage, to get the 12v DV to 300, and then using a H bridge to get AC, the problem is that in the first stage i can't get 300v, im using 200KHz PWM, and a ferrite transformer, i think the problem might be the transformer specs, im not sure, or should i use H-Bridge instead of the push-pull, and also at the output how can i get a 220v AC sine wave?

thanks,

electro13

Hi Electro 13 . i can offer you , to read this thread from first page up to latest page . then if you've any question , you can ask .

Now I've some observation and queries -
1. For rectifier, I found two diode MUR1560 and MUR3060 having the same price (BDT90). Didn't find any other diode of MUR series. I do not need such high current like . So, could you please suggest any other diode applicable here and available in BD market?

Hi Sam ,
Sorry for delayed answer . i was terribly busy .
you can try to find some diodes in with part number of DSSKXX too .

2. Still unclear about choosing ferrite core. I was unable to make clear my requirement to Goldsmith . Filter is for making pure dc from the rectifier output to be used as input for the inverter stage.

An advise , try to understand why a ferrite core is used and what is the duty of a filter or a transformer in your circuit . if you think about it , more deeply , you'll get your answer . but if after thinking about these issues you can't get the point , tell me again , i'll tell you the answer .

3. From another thread I found a suggestion to use IRFP460 (500v, 20A, 0.27ohm) for inverter stage. It costs BDT150. I found IRFP450 (500v, 14A, 0.31ohm) which costs lower than BDT100. For my application doesn't require such high current. I think IRFP450 should be okay. Please let me know if there is nay other drawback of this. Also suggest any available effective alternative MOSFET.

There are several options available . such as what Tahmid have suggested you .
From my side : IRFP460 . IXTH13n110 or some other productions of IXYS corporation .
or perhaps 2SK2611 or ... etc .
Best Wishes
Goldsmith

 

[sam781]

Thanks a lot both of you

I bought cheaper devices to do my job. I bought Diode MUR460 for bridge rectifier at transformer output and IRF840 for Inverter bridge. I already had IRF3205 for converter bridge. I've completed transformer winding with lower number of wires (14 sw-24 instead of 34) in primary. Secondary is ok. Let's see finally how much loaf it can cater. :smile:

But the problem I've faced just now is with converter bridge. While making ready my circuit to test transformer, I powered up the bridge and the driver ICs (IRFP2110) without powering up the microcontroller. PIC micro controller is for generating gate signal for converter bridge. As soon as I connect +12 supply with the MOSFET bridge I observed smoke at the ground connector of the Bridge. Left bottom MOSFET was hot, most probably it is damaged. One MOSFET driver IC was also damaged. Another Driver is ok. I do not have a spare MOSFET and driver IC to recheck the circuit again. I've to buy these to test again. But I don't know why this incident occurred. :sad: The MOSFETs should not be on if no gate signal is applied.

 

[goldsmith]

dge. Left bottom MOSFET was hot, most probably it is damaged. One MOSFET driver IC was also damaged. Another Driver is ok

Hi Sam
Do you have dead time ( enough dead time ) in your driving signals ?

 

[sam781]

Hi Sam
Do you have dead time ( enough dead time ) in your driving signals ?

Yes, but the problem is when I power up the bridge circuit gate signal was not there because microcontroller was off.

- - - Updated - - -

currently duty cycle is set as 90%