i need 12V DC to 220V AC inverter circuit

[Audioguru]

How can I remember you?
Lots of people post schematics with dots all over them with a grey background and zipped into a fuzzy JPG file type.
They even post it at another website that takes forever to wake up.

 

[Fidelis Anyanti]

I see, looks like you dont use Isis Proteus, else you wont find those dots so annoying. For your sake, i suggest you get Proteus.

Moreover, i doubt you will stop seeing those dots.

 

[karesz]

Hi Fi-delitus!
Why can you (both) not write some over the topics subject pls?
In normal circuit you must have dots= point after these writings_finished the film
K.

 

[KRYCHEK]

Fidelis Anyanti

Thank you so much for that diagram, i have a little query, will i need 2 of those circuits as i have 2 pulse 180 degress out of phase coming out of my sg3525, and will i need any filter to get the sine wave, i am using multisim doesnt seem to be any good

thanks again

 

[Fidelis Anyanti]

Hi KRYCHEK,
yes you need two identical circuits to receive the two half cycle outputs from your SG3525.

I use isis proteus, i used multisim before, i think it's good. Proteus tends to have a lot of functionality.

 

[KRYCHEK]

hi Fidelis Anyanti,

i have drawn the circuit up but it does not seem to work, what are the capacitor values and are there electrolytic ?

the sg3525 is at 50hz and drives the h bridge






we need more people like you Fidelis, the world would be such a happy place.

 

[KRYCHEK]

Hello there and Blessings upon u my brothers,

I have two complementary pulses from an sg3525, any ideas of directions in how may i convert these into two complementary sinewaves

Blessings my brothers

 

[Fidelis Anyanti]

Hi, Krychek.

My brother, sorry i've been away for some time now. Duty called.

However, the squaretosine wave circuit above should work. Build it and try it out.
The caps are small value electrolytics. This is integrator circuit so you will need to build and feed your complementary pulses to them. Note that these are opamps, when you feed square wave in, the first opamp converts it to triangle wave, and the second opamp converts it to sine wave.

Stay Blessed.

 

[KRYCHEK]

Thank you Fidelis Anyanti,

I have a 2nd question, which u may know of,

In a switchmode Inverter, why is the DC BUS VOLTAGE stepped up to 350 V, I mean why is it so high.

I think am done now Thanks alot for your help

 

[Fidelis Anyanti]

Hi, Krychek.

you know that in a switch mode inverter, you use chopper transformer circuit to generate voltage high enough to deliver your voltage requirement. However, Choppers dont work @ low frequencies so, this way there is power conversion with low loss because
chopper transformers dont saturate like iron core transformers.

Now check out this circuit updated from the last one i posted. Notice the two upper drain terminals detached from the 12v dc
rail and taken to DC bus coming from your battery boost module. Your 220V ac load is driven from the middle of your
H-Bridge circuit.Because of normal semi-conductor impedance and voltage drop, not all the 350v gets to your load even.

You can see that, no transformer is used to drive the load, just the H-Bridge.To do that, the voltage must be high.

Have a wonderful day my brother.[/img]

 

[Audioguru]

In a switchmode Inverter, why is the DC BUS VOLTAGE stepped up to 350 V, I mean why is it so high.

The peak voltage of a 240VAC sine-wave electricity is 340V. Add 10V for losses then you need a supply voltage of 350VDC to produce a sine-wave of 240VAC.

 

[KRYCHEK]

Thats great ,well understood, i am just thinking, can this single phase inverter be converted to 3 phase inverter, i know in 3 phase the firing angles are seperated by 120 degrees, how is this accomplished, how to fire three phases in 120 degrees seperation. very much appreciated. Gods blessings to you, stay in touch.

 

[KRYCHEK]

Hello I am wondering if anyone can help me.

On a H bridge- which is provided using constant Dc voltage,when the gate is a logic high, what happens to the mosfet ? does it still be on or off, and what happens when logic to mosfet is low, when the drain is still supplied using high dc bus.

Thanks help appreciated

 

[Audioguru]

Hello I am wondering if anyone can help me.

On a H bridge- which is provided using constant Dc voltage,when the gate is a logic high, what happens to the mosfet ? does it still be on or off, and what happens when logic to mosfet is low, when the drain is still supplied using high dc bus.

Thanks help appreciated

You make no sense.
N-channel or P-channel Mosfet?
Logic-level or 10V gate level Mosfet?

An N-channel Mosfet is turned on when its gate voltage is 5V or 10V more positive than its source voltage.
A P-channel Mosfet is turned on when its gate voltage is 5V or 10V more negative than its source voltage.

If the gate voltage is not enough for the Mosfet then it turns on weakly and gets very hot.

 

[KRYCHEK]

Hi, sorry what i meant to say was an , N- channel mosfet, driven using Mosfet driver.

For example a pair of mosfets configured as a push-pull, pulsed using and IR2101, (High and Low side driver).

Both drains are constantly provided using a high DC bus of 350V, how does this still enable the mosfets to operate in a H bridge, in order to provide AC

hope am clear.

 

[Audioguru]

A Mosfet driver IC allows all N-channel Mosfets in an inverter to operate push-pull.
Only one drain connects to the high voltage supply and the drain of the other Mosfet connects to the output.

 

[KRYCHEK]

That is not correct,

please refer to the diagram above posted by fidelis, h bridge

both drains are supplied using high dc bus 350v.

but still how is the ac achieved,

 

[Audioguru]

That is not correct,

please refer to the diagram above posted by fidelis, h bridge

both drains are supplied using high dc bus 350v.

but still how is the ac achieved,

There are 4 Mosfets in a bridge, not just 2.
The high side Mosfets have their drains at 350VDC and the low side Mosfets have their drains at the output like I said.
They alternate and make AC.

 

[KRYCHEK]

1,How do you switch the n channel devices on/off for the high side driver?

2,How is the gate related to the source when trying to switch the device on?

Thanks Audi guru

 

[Audioguru]

The gate voltage for most N-channel Mosfets must be 10V more positive than its source voltage for it to conduct well. A "high-side-driver" IC can do it.