ic8038 can this work

[burai]

hi every one
my first post in the forum
hope welcome
im plan to make inverter
by using ic8038
it generate sine wave signal
can this circuit work

 

[Audioguru]

The ICL8038 is obsolete and not made anymore.
No your circuit will not work because both transistors have the same input signal then their outputs are the same and are not push-pull. The simple transistors are not power amplifiers anyway.

If you amplify a sinewave with a linear amplifier then the amplifier wastes a lot of power by getting hot. An inverter with a sinewave output uses Pulse-Width-Modulation or a class-D switching amplifier that does not waste power making heat.

 

[burai]

thanks mr audioguru
Excuse me im bad at english
im think to use that sine wave signal
also i know that the circuit most contain push pull stage
now if i replace ic sg3524 with
two ic8038
can it be or the same error

 

[Audioguru]

The SG3524 produces a squarewave output that switches high with a small voltage drop then it switches low with a small voltage drop. With low voltage drops then it does not waste a lot of power making heat like your crazy idea of using a sinewave generator and a linear amplifier that gets hot. This SG3524 circuit uses a small amount of PWM to regulate its average output voltage. The output of this SG3524 inverter is a squarewave, not a sinewave.

Modern sinewave inverters use PWM switching for low heating but modulate the high frequency pulses with a low frequency sinewave. Then they smooth the high frequencies away with an output filter.

 

[FvM]

Presumed you want to design an inverter with linear power amplifier rather than usual PWM output stage. Then the output stage must be designed as voltage amplifier similar to a linear audio power amplifier. The output stages you have shown so far are pure switchers and can't achieve linear voltage amplification.

 

[betwixt]

...and it's doubtful the SG3524 could produce enough voltage to fully drive that many transistors anyway.

Brian.

 

[Audioguru]

...and it's doubtful the SG3524 could produce enough voltage to fully drive that many transistors anyway.

Brian.

I calculated the voltage loss when the TIP122 darlington is driving two power transistors and they all are connected as a darlington. The transformer is still spec'd at 12V for each half so it will get only about 8V peaks instead of 12V peaks then the transformer squarewave output will have peaks of only 147V instead of 220V.

 

[burai]

The SG3524 produces a squarewave output that switches high with a small voltage drop then it switches low with a small voltage drop. With low voltage drops then it does not waste a lot of power making heat like your crazy idea of using a sinewave generator and a linear amplifier that gets hot. This SG3524 circuit uses a small amount of PWM to regulate its average output voltage. The output of this SG3524 inverter is a squarewave, not a sinewave.

Modern sinewave inverters use PWM switching for low heating but modulate the high frequency pulses with a low frequency sinewave. Then they smooth the high frequencies away with an output filter.

All what i think about
is that generate 220 ac from 12 ac without ripple
for that i think i can use sin wave source
thank mr Audioguru
now i understand thate connect 2 transistor in series with same input signal will make them short circuit
thanks
also Excuse my bad english

 

[burai]

...and it's doubtful the SG3524 could produce enough voltage to fully drive that many transistors anyway.

Brian.

first im here because before 2 week ago i see one of your
reply for someone
it help me
and now i see all the magic here in this forum as good people

now if sg3524 not work here
as i understand from your reply
sorry may you suggest another way or another ic
also mr betwixt Excuse me im bad at english

 

[burai]

Presumed you want to design an inverter with linear power amplifier rather than usual PWM output stage. Then the output stage must be designed as voltage amplifier similar to a linear audio power amplifier. The output stages you have shown so far are pure switchers and can't achieve linear voltage amplification.

thank mr fvm for reply
if i design circuit like audio amplifier that amplifer 3 or 4 volts sine , 50 hz
and feed them to transformers to be 220 ac 50 hz
can it be

 

[Audioguru]

You did not say how much 220VAC power you want. If you want 500W then a linear audio power amplifier will produce about 400W of heat. If the output from the amplifier is only 4V at 500W then the peak current in the amplifier output is 88A which is a lot of current. The battery that powers this inverter must provide 900W of power.

 

[burai]

You did not say how much 220VAC power you want. If you want 500W then a linear audio power amplifier will produce about 400W of heat. If the output from the amplifier is only 4V at 500W then the peak current in the amplifier output is 88A which is a lot of current. The battery that powers this inverter must provide 900W of power.

ok mr Audioguru
i need 220v ac . 50hz
power 3000 w
so
i will start to make the circuit
with pwm model
using pic microcontroller
and post the circuit here
thanks for help

 

[Audioguru]

3000W is a lot of power. Why don't you use common ordinary household electricity? A 3000W PWM sinewave inverter will probably produce 225W to 450W of heat.

 

[betwixt]

Burai - firstly, your English is good, no need to be sorry!

You need to understand there are several ways to generate 220V AC with 3KW capability but it is technically quite difficult. The main problem isn't how you produce the AC, it is simply the amount of current the circuit needs to work properly. Power = Volts x Amps or looking at it the other way, Amps = Power/Volts. So the current needed to produce 3KW from 12V is at least 3000/12 = 250 Amps. That assumes 100% conversion efficiency which is not possible in real life.

You say you want to start from 12V AC (post #8) so the simplest way is a step-up transformer but it would be very large, expensive and heavy (two people to carry it!). Where is the 12V AC @250 Amps coming from anyway?

If you want to convert 12 DC to 220V AC there are three practical ways to do it:

1. Build a 'modified' sine inverter. This does produce AC but it is not a sine wave, it is like a square wave with a 0V period before and after the zero crossing time. It is the easiest to build but because the waveform has sudden rising and falling edges, it will not drive some loads properly, in particular, it will not drive motors or transformer loads efficiently and if they do run, they may be noisy or overheat.

2. Build an analog sine inverter. This is a sine wave oscillator and a powerful amplifier to increase the power. I think this is what you originally had in mind. It works, but there is a serious problem, such amplifiers are very inefficient, maybe 70% at best. That means to get 3,000 W out, you need to supply the amplifier with about 4,000W and force remove the 1,000W of heat it will produce. It would also need about 350A of current from 12V to operate it.

3. Build a PWM inverter. This is the most complicated but efficient method, it can reach efficiencies of > 90%. You start by generating a high DC voltage using an efficient high frequency inverter then 'chop' the DC using a PWM driver circuit to produce the low frequency sine wave from it. Because it relies on high speed power switching you can not use transistors like the 2N3055, you have to use power MOSFETs and special gate driver devices. There are many designs on the internet that use this method but I warn you they are complicated to build and, as many on here will tell you, are not forgiving if something goes wrong. I'm sure most people on here who have designed and built PWM power supplies will have seen smoke coming from them!

Brian.

 

[burai]

3000W is a lot of power. Why don't you use common ordinary household electricity? A 3000W PWM sinewave inverter will probably produce 225W to 450W of heat.

yes it's alot of power
but i have to do it
no i can't use household electricity for the application
you know mr audioguru i assume you think all about dissipation as heat
it because my plan is doubtful
as it clear i can use either
modified sin model or pure sin wave model
thanks you for being helpful

- - - Updated - - -

Burai - firstly, your English is good, no need to be sorry!

You need to understand there are several ways to generate 220V AC with 3KW capability but it is technically quite difficult. The main problem isn't how you produce the AC, it is simply the amount of current the circuit needs to work properly. Power = Volts x Amps or looking at it the other way, Amps = Power/Volts. So the current needed to produce 3KW from 12V is at least 3000/12 = 250 Amps. That assumes 100% conversion efficiency which is not possible in real life.

You say you want to start from 12V AC (post #8) so the simplest way is a step-up transformer but it would be very large, expensive and heavy (two people to carry it!).

thanks for explaining mr betwixt
there are a lot of things i understand it now.

Where is the 12V AC @250 Amps coming from anyway?

yes but it just a thinking for solution, but it can't be , because it need linear power amplifier and it inefficient also the 250 amp can't be.

If you want to convert 12 DC to 220V AC there are three practical ways to do it:

1. Build a 'modified' sine inverter. This does produce AC but it is not a sine wave, it is like a square wave with a 0V period before and after the zero crossing time. It is the easiest to build but because the waveform has sudden rising and falling edges, it will not drive some loads properly, in particular, it will not drive motors or transformer loads efficiently and if they do run, they may be noisy or overheat.

2. Build an analog sine inverter. This is a sine wave oscillator and a powerful amplifier to increase the power. I think this is what you originally had in mind. It works, but there is a serious problem, such amplifiers are very inefficient, maybe 70% at best. That means to get 3,000 W out, you need to supply the amplifier with about 4,000W and force remove the 1,000W of heat it will produce. It would also need about 350A of current from 12V to operate it.

3. Build a PWM inverter. This is the most complicated but efficient method, it can reach efficiencies of > 90%. You start by generating a high DC voltage using an efficient high frequency inverter then 'chop' the DC using a PWM driver circuit to produce the low frequency sine wave from it. Because it relies on high speed power switching you can not use transistors like the 2N3055, you have to use power MOSFETs and special gate driver devices. There are many designs on the internet that use this method but I warn you they are complicated to build and, as many on here will tell you, are not forgiving if something goes wrong. I'm sure most people on here who have designed and built PWM power supplies will have seen smoke coming from them!

Brian.

from your reply and other book
i can build (pure sine inverter )
sorry i forget to say that it build to use in inductive load
and some_ in case if it ok_ expensive equipment.

or if i decide
number 3 from your reply
is these way fit for medical equipment ?
yes it difficult but i have to try to understand more
about build and move between electronic and electric

thanks you