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Inverter Circuit 12V DC to 230VAC Sine Wave


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MP,
Is your proposed digital sine wave amplifier or inverter with "varying heights of its steps" on the web?
What would be its efficiency as an amplifier or inverter?

I showed a square-wave inverter and a modified sine-wave inverter with large digital steps with a pause in between. Their efficiency using transistors is about 80%, about 90% when using Mosfets.
I showed a digital PWM class-D amplifier that could be an inverter. Its efficiency is about 90%.

You showed an analog sine-wave inverter with an efficiency of only about 60%.
How on earth could a sine-wave be made with pulses of varying heights and not waste a lot of power? ???

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You showed an analog sine-wave inverter with an efficiency of only about 60%.
How on earth could a sine-wave be made with pulses of varying heights and not waste a lot of power? ???



Actually, I have not shown you a design of anything. Is it common for a theory expert to build a complete inverter from a picture of a pulse? Perhaps you did not build it well.

MP
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audioguru,
PWM isn't digital, it's squarewave who's duty cycle depends on an external signal, you could also look at it as a complex wave with harminics from both the carier and modulating signal up to (in theory) infinity, on the output of the amplifier is a low pass filter that only passes the lower audio frequencies. Digital is totally differant it's used where tow states represent 0s and 1s, the only thing PWM has in common with digital is the transistors are either on of off. I wish people would stop calling class-D amplification digital - it's very confusing, even more so to newbs.

MP,
I'm very interested about you would go about generating differant voltage steps without loosing a hell of a load of power or using a switching regulator which would be  effectively  class-D amplification anyway.

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Hi Alun,
Of course I know that a PWM class-D amplifier isn't truely digital with 1's and 0's.
It isn't truely analog either, it is a switching type.

My extremely low distortion sine-wave generator uses varying step heights like MP's idea.
It uses a CD4018 Johnson walking ring counter driving 4 resistors with special ratios to produce a sine-wave with 10 steps and no distortion up to the 9th harmonic.
I use a switched-capacitor lowpass filter IC to remove remaining harmonics. ;D

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OK guys,
Mixos should have a contest.
We can combine the last few posts which have all the ingredients to make a powerful, efficient, voltage-regulating pure-sine-wave inverter. Like the Compact Fluorescent Driver, it can even have a ground-fault interrupter built-in.
It can use any of the SMPS PWM controller ICs like Sasi's european one or the TL494 or TL497. It can use as many Mosfets as you like for tonnes of power.

A good challenge for me, but what do I need an inverter for with Niagara Falls nearby churning-out kilo-megawatts continuously? My ship is beached (my joke on another forum where everyone pins their locaton on earth-google's satellite-pics globe), so I can't use an inverter there.

Here's what a PWM stepped sine-wave looks like:

post-1706-14279142431896_thumb.gif

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You showed Ante's analog sine-wave inverter with an efficiency of only about 60%.

EDIT: The output Mosfets operate in class-A, so the inverter's efficiency might be as low as 33%.


Just passing on something that ante posted years ago. Not my design, nor have I made the circuit. If you go back and read the posts, you will see that I was talking about several different methods, but not advising to use any particular one. I think you take posts much too personally, audioguru.....and it seems that when you have the urge to argue with someone, you twist the quotes to make fuel for your argument. (for example, trying to prove class D is digital, then admitting to alun you knew it was not). I will not add to this kaos. There is no longer anything constructive in this conversation.

MP
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Phase Controlled Charger Circuit

Features:

Constant Current & Constant Voltage charging,Precise Cutoffs & Trickle Chraging

We Sell this circuit  as  a Seperate charger for People Who want Battery Chargers/self Start Generators

As For Sasi's  over heating of 0-180 Coil we use a 10 Ohm, 40 Watt Resistor in series with the 180 Tapping.

People who have used this charger said that it was Better than an SMPS Charger  .

People in country like ours (Rural Population)cannot afford  a very expensive inverter which needs high Bill Of Material (Inverter trafo + Charger Trafo + Mosfets+3055  transistors+Relays etc). ???

the inverters based on this kind of charging are alive since 6 years to tell their success story. ;D

i have to take these Pics because the Publisher and the Editors have Painstakingly  decoded the Inverter & UPS  PCBs available in the market for training the Students & hobbyists . They deserve their own credits. :D


arun  ;)

post-8859-14279142436489_thumb.jpg

post-8859-14279142436843_thumb.jpg

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Nura,
It looks like Sasi perfected the original inverter circuit.
It had a common-emitter transistor in the output of the IC driving another common-emitter transistor driving a complementary pair of emitter-followers, while Sasi replaced them all with simply an emitter-follower and used the transistor in the output of the IC also as an emitter-follower.
Sasi's circuit does the same job with far fewer transistors for each side and turns-off the Mosfets quicker too. It also might even turn-on the Mosfets quicker. His quicker switching results in less power and heat wasted. :P
There are many ways to skin a cat and cats look similar at 1st glance.

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Nura,
Would it be possible for you to scan the book into a pdf file or word document to share with the group? Or is this a copyrighted document? In this case, what is the ISBN number so that others can look for this book?

Also, I wanted to mention that there are perhaps thousands of variations of inverter circuits. So, we should try to keep from arguments such as who invented an inverter design or who improved one.

MP

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