Hi all

I have finished of design and implementation for pure sine wave inverter , first stage use push-pull to convert 12v dc to 310v dc with feedback , so no problem with load in dc side range measure between 35 to 315

The problem in H-bridge mosfet using pic uC as signal , under 100w load , I get pure sinewave form and ac side 220v aprox. , but when add more load the signal convert to more like triangle not sine.

is sinewave inverter have feedback? , all tutorial on internet explain how to make sine wave signal from lookup table , is there secret , no full detail can u find for puresine wave inveter

 

any help?

 

is sinewave inverter have feedback?

Yes, if you want to maintain a steady RMS output amplitude under varying load.

 

As you can see in video after changing SPWM pulse in software , I got this sinewave

the problem is AC voltage is low you can see it's 204v although DC voltage 330v

how can increase amplitude , the duty cycle in degree 90 of since wave about 95% ,no change to increase it

 

first stage use push-pull to convert 12v dc to 310v dc with feedback

If you're now getting 330VDC it seems the feedback isn't working?

 

If you're now getting 330VDC it seems the feedback isn't working?

no feedback work well , I increased it to 330 , because I can't get more than 200v ac
if I decrease it to 311dc the ac voltage will be 195v

 

Post your schematic.

 

Post your schematic.

I have not fixed schematic , I asked for what's the reasons of low voltage amplitude

 

I have not fixed schematic , I asked for what's the reasons of low voltage amplitude

I perfectly understand your question.
And I can best answer that if I can see the circuit.
Otherwise it's just a WAG.

 

I perfectly understand your question.
And I can best answer that if I can see the circuit.
Otherwise it's just a WAG.

I have not drawn circuit I used driver from different circuits ,it's TLP250 drive H-Bridge mosfets , voltage signal in gate from 10 to 10.8 according to oscilloscope

 

Then draw it. Talking about a hypothetical circuit that could be connected in a hundred different ways is pointless.

 

Then no idea from any preson , , at least theoretically

 

Then no idea from any preson , , at least theoretically

In theory, if you know how you assembled the circuit, you should be able to use a simple pencil or pen, draw the circuit in a piece of paper, take a picture of the paper with your phone and post said photo to this thread. But theory and practice are not always the same.

 

Then no idea from any preson , , at least theoretically

Theoretically, there's likely an error in your circuit.
Where is anybody's guess.

 

Theoretically, there's likely an error in your circuit.
Where is anybody's guess.

I think it is beyond theory, I think we can agree a circuit error is a fact. Unless, of course, it is a failed component. Or an operator error. Or a...

Ok, we are back to theory.

 

If you can't exert the effort to draw and post a schematic of your circuit (and I don't see how you can build a circuit without one), then I'm not going to exert the effort to try to guess what's wrong.

 

If you can't exert the effort to draw and post a schematic of your circuit (and I don't see how you can build a circuit without one), then I'm not going to exert the effort to try to guess what's wrong.

I will try to draw it,if I have time