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Fly back converter design

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atiq ur rehman

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hi everyone there :)

i m working on a inverter for which in first step i m designing a module for boosting up the voltage. here are two things i want to know.

1) i want to invert the boosted voltage to around 230 volts. how much should i boost the voltage and what is the criteria of determining it ?

2) i need 50Hz at the out put while designing a flyback boost converter i need to increase my frequency ! wanted to know that how will i get the desired frequency at the out put when it is already increased in K's.

Please help me out by answering my questions
Regards :| :)
 

Are you boosting it up from 12V/24V? Is this for an inverter? What is the power rating?

I think you need a good amount of power (> 100W). So, you should use push-pull instead of flyback. Use a ferrite transformer to boost the voltage. At the output, rectify and filter.

Then, you need to convert to 50Hz using a full-bridge converter.

Hope this helps.
Tahmid.
 

Then, you need to convert to 50Hz using a full-bridge converter.



Hello Dear atiq ur rehman
And hello Dear Tahmid
I think tahmid forgot to say , that , the second stage should drive with SPWM with 50 HZ message signal and it should not has transformer ( this stage ) . and it need a filter at out put with F0 =5KHZ !!!
Best Wishes
Goldsmith
 
goldsmith said:
Then, you need to convert to 50Hz using a full-bridge converter.



Hello Dear atiq ur rehman
And hello Dear Tahmid
I think tahmid forgot to say , that , the second stage should drive with SPWM with 50 HZ message signal and it should not has transformer ( this stage ) . and it need a filter at out put with F0 =5KHZ !!!
Best Wishes
Goldsmith
Click to expand...

The filter depends on the modulation frequency. It could change if modulation frequency was 16kHz, 64kHz or anything. Anyways, thanks for mentioning that. I forgot to mention that.

Also, you should use a proper high-low side driver.

Hope this helps.
Tahmid.
 

Tahmid bhai

i m designing a 1.5Kw inverter , my input is 24Vdc and out put is 230V ac (8-10 Amps)
y to use a push pull and y not a fly back topology. can we boost voltage using a push pull configuration to around 650Vdc?
and please can u tell me for this much out put which pwm controller shoud i use ? i have searched many pwm controllers but they are used in stepping down the voltage like LM5030 PWM Push-Pull Controller and not for boost purpose.

Regards

---------- Post added at 19:41 ---------- Previous post was at 18:42 ----------
Tahmid said:
Are you boosting it up from 12V/24V? Is this for an inverter? What is the power rating?

I think you need a good amount of power (> 100W). So, you should use push-pull instead of flyback. Use a ferrite transformer to boost the voltage. At the output, rectify and filter.

Then, you need to convert to 50Hz using a full-bridge converter.

Hope this helps.
Tahmid.
Click to expand...


Tahmid bhai

i m designing a 1.5Kw inverter , my input is 24Vdc and out put is 230V ac (8-10 Amps)
y to use a push pull and y not a fly back topology. can we boost voltage using a push pull configuration to around 650Vdc?
and please can u tell me for this much out put which pwm controller shoud i use ? i have searched many pwm controllers but they are used in stepping down the voltage like LM5030 PWM Push-Pull Controller and not for boost purpose.

Regards
 

1.5kW is WAY beyond the range of flybacks if you want a good reliable circuit without EXTRAORDINARY stress on the switches.
At 1.5kW, it's better to use full-bridge, but you can use push-pull.

LM5030 is good. It's a current-mode controller. But you can also make do with voltage mode controllers like SG3525.

Why do you need 650V? You should be looking at around 300-370V depending on, if you want square wave or modified sine wave or pure sine wave output.

10A output at 230VAC is not 1.5kW, it's 2.3kW.

Hope this helps.
Tahmid.
 

Why do you need 650V? You should be looking at around 300-370V depending on said:
Tahmid bhai

in the start my first question was to tell me about the voltage that how much should i boost it? what in my mind was that generating around 220V AC i will need 330V peak voltage and 650 volt peak to peak. so for 650 volt peak to peak i need 650V DC. but i dont know by using half bridge or full bridge which difference does it make ? i think for half bridge we need 650V and for full bridge we use 325V (am i right?).

---------- Post added at 01:10 ---------- Previous post was at 01:07 ----------

Dear Tahmid
can u please give me something to study on it or some sort of design that coul help me out if u have worked upon it (for push pull )

Thanks
Regards
Click to expand...
 

You have to boost it to around 330V, not 650V. The change of polarity is done by the bridge rectifier by changing the direction of current flow, effectively switching from 330V in one direction to the other in the next cycle, so switching (with reference to one output) from 330V to -330V.

For ground referenced half-bridge, you need 650V.

You can start from here:
**broken link removed**

Hope this helps.
Tahmid.
 

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