Another INVERTER we can talk about..

[audioguru2]

The circuit you posted with a linear sine-wave from Mosfets uses an XR-2206 function generator IC to make the sine-wave, not a square-wave. I don't think the XR-2206 is made anymore.
The 500W square-wave inverter project on this site uses a Cmos CD4047 IC to make the square-wave. It has a Cmos oscillator, a digital divider to make a perfect 50:50 square-wave, a direct output and an inverted output.

 

[kachew]

oh i see.....then is there IC would replace the previous 1? and the multiplier in the circuit..what is the usage?? just multiply the current or it have other usage? and its port connected to an XOR to invert the waveform ?? because the input from the multiplier is always big so it is 1 and the function generator will give 1 and 0 so the output from the XOR will be inverted??? ??? ???

 

[faizanbrohi]

For your Kind Information AUdio Guru , i think XR2206 is being manufactured . It is not yet outdated.

 

[audioguru2]

The MM5389 counter is also not made anymore. If the accuracy of a quartz crystal isn't needed then the oscillator in the XR-2206 can be used instead.

 

[faizanbrohi]

Well using a modified sine wave won't hurt . What about your sine wave inverter audio guru , that you were making using Texas instruments CLass D Amplfier IC's

 

[kachew]

dear audioguru

the XR 2206
port connected to an XOR to invert the waveform ?? because the input from the multiplier is always big so it is 1 and the function generator will give 1 and 0 so the output from the XOR will be inverted???

 

[audioguru2]

the XR 2206
port connected to an XOR to invert the waveform ??

The output current from the MM5369 is very low, so an XOR is used to increase the current. It doesn't need to be inverted and works the same if it is inverted or not.

because the input from the multiplier is always big

The MM5389 will try to give a 12V output but is clamped to 5V by the input protection diodes of the XOR.

so it is 1 and the function generator will give 1 and 0 so the output from the XOR will be inverted???

The function generator needs a perfect square-wave at its input. The output of the MM5369 is not perfect, it has assymmetry, so the XOR drives a filter.

 

[kachew]

if so...then i can straight use the xr2206 by changing the value of the capacitance and resistance shown in the datasheet to get 50HZ? in the datasheet there is many ways to generate the sine wave...which 1 should i choose? sinewave generation without external adjustment or sinewave with minimum harmonics distortion? and what is the different between this 2 circuit? thanks ;D

 

[audioguru2]

If you use parts that have a 5% tolerance then the frequency could be 45Hz to 55Hz. If you use an adjustment pot then it will be 50Hz or whatever you adjust it to.
You probably don'y need an adjustment to minimise distortion in an inverter.

 

[kachew]

dear audioguru
oh now i see....can u pls explain the usage both of LM 324 in the circuit diagram?? because in the datasheet i cant find and similarity circuit in it for the application especially in the driver part there....thanks for your reply

 

[audioguru2]

can u pls explain the usage both of LM 324 in the circuit diagram??

One opamp inverts the output of the XR-2206, one makes a +6V reference voltage and two are amplifiers with the Mosfets with overall negative feedback from the output of the transformer.

 

[kachew]

hi audioguru,
can i add more mosfet and caps to increase it performance aslo efficiency?? or Do you have any suggestion?? thanks for your reply.....

 

[kachew]

hi audioguru..

i still dont understand why we want to invert the signal from XR2206?? and why we need to have voltage reference 6V?? thanks for your information ??? ???

 

[audioguru2]

can i add more mosfet and caps to increase it performance aslo efficiency??

Of course adding Mosfets will result in the same total amount of power wasted as heat because the Mosfets operate as a linear amplifier. Therefore the low efficiency will be exactly the same.
You could add more Mosfets to share extra heat and get more power output.

Which caps have anything to do with efficiency?

why we want to invert the signal from XR2206??

The transformer is driven push-pull so the Mosfet on one side needs its drive to be inverted.

why we need to have voltage reference 6V??

All opamp circuits need a DC reference voltage. This one is half the supply voltage.

 

[kachew]

dear audioguru...
is there any alternative way to increase the efficiency without using the pwm?? and the negative feedback u meant is used for?? ??? ???

 

[audioguru2]

is there any alternative way to increase the efficiency without using the pwm??

Make the circuit switch and produce a modified sine-wave that is a square-wave with a couple of steps in it. Switching circuits are much more efficient than linear circuits.
Use a ferroresonant transformer with a square-wave driving it.

and the negative feedback u meant is used for??

It keeps the output voltage regulated so that it doesn't drop with loading.
It also keeps the output a sine-wave when a non-linear load tries to make it distorted.

 

[indulis]

This is a linear sine-wave inverter and it wastes a lot of power and its output Mosfets get extremely hot because they conduct a high current all the time.

Did you consider that the MOSFETS run for a long time in their "Ohmic Region" as the cause of them getting hot?

Since the current, like the voltage, is a sinusoid, at "crossover", the MOSFET's shouldn't  be conducting any current at all.

All opamp circuits need a DC reference voltage. This one is half the supply voltage.

As a general statment, that's a little misleading to those that aren't familar with op-amp circuits. Yes a reference is chosen, but it can also be ground just as easly as a DC... or for that matter, an AC signal.

 

[audioguru2]

Since the current, like the voltage, is a sinusoid, at "crossover", the MOSFET's shouldn't

 

[kachew]

Make the circuit switch and produce a modified sine-wave that is a square-wave with a couple of steps in it. Switching circuits are much more efficient than linear circuits.
Use a ferroresonant transformer with a square-wave driving it.

dear audioguru,
do you have any suggestion to modify the circuit as u meant ??? the cost isnt a problem as i know you said before the ferroresonant transformer is expensive enough.....i just want to learn more about the inverter projects  ;D ;D ;D so after i can sucessful make it work so i can share to other ppl in this forum

 

[audioguru2]

A modified sine-wave is better than a square-wave for many electronic products as their mains, but still isn't good enough for some electronic products.
I think inverters for expensive TVs and computers should use PWM to make a regulated sine-wave.