[SOLVED] Pic 16f876a Pure Sinewave inverter

[conglyhd]

Hi Taner!
You would do me Files printed circuit PCB can now be printed using a normal printer. Thank you very much!

 

[jami007]

hi everybody i've made the PCB of the inverter and modifying it to make UPS, it needs professional soldering. soon i'll upload the inverter PCB after printing it and varifying for any fault.and soon i'll upload whole project with all paper work i've done so far. . . . so be patient. . . .Taner or anybody can u plz tell me, is there any fault in the code? plz reply fast because i've only one month left to submit my final year project

Added after 36 minutes:

also tell me what is the max output current of the CT.

can any one varified vref values in the code by formula Vref=(Vpsin(2*pi*k))/N? k is sample no, N is samples per cycle and Vp=1.5(Vout*sqrt2).

what is max GAIN of the ADC in counts per output?

can i use two inductors instead of inductive choke?

instead of using dual zenar can I use 2 zenars of 2.4v?

Added after 57 seconds:

also tell me what is the max output current of the CT.

can any one varified vref values in the code by formula Vref=(Vpsin(2*pi*k))/N? k is sample no, N is samples per cycle and Vp=1.5(Vout*sqrt2).

what is max GAIN of the ADC in counts per output?

can i use two inductors instead of inductive choke?

instead of using dual zenar can I use 2 zenars of 2.4v?

 

[conglyhd]

Hello!
I am not specialized in electronics, but want to make inverter.
Hope your help.
please post in PCB circuits, printed circuit boards that you have made successful.
thank you very much!

 

[RF_Burns]

Wow, I am very happy to find this!!

I have been trying to make a replacement inverter for my old motorhome refrigerator for several years. The refrigerator has a compressor that works on 28Vac 60hz. It has a transformer to reduce 120Vac to 28Vac, and it also has a winding operated through a square-wave inverter to operate on 12Vdc.

The best I have done so far is to replace the 30+ year old inverter circuit with a PIC driving logic level MOSFETs. The 12V winding is a split winding so I have 2 MOSFETs in push-pull now. Of course it makes a Buzz noise.

Would I simply need to change the transformer to a 28V output to use your circuit?

The compressor is under 60watts of power, so much less than this design.

Any ideas would be appreciated!

thank you
Bruce

 

[@t]

The 12V winding is a split winding so I have 2 MOSFETs in push-pull now. Of course it makes a Buzz noise.
Would I simply need to change the transformer to a 28V output to use your circuit?
The compressor is under 60watts of power, so much less than this design.
Bruce

Hello Bruce, it's not my circuit, but I would say that indeed an adaption of the transformer ratio is a solution for you. I would go for a bit more than 28v because you can regulate the output down. And your power requirement is nice low.
Why don't you control the original 12v trafo connections directly?
The nice thing here is the sinewave of course, if that software is functioning ok is the question, you can see some remarks from different people. I have not try'd it yet, I like to make a Basic/asm version of it sometime.
At.

 

[matteod76]

hello, I wanted to know if a friend tried to change this inverter.in 24v out 230v.thanks

 

[RF_Burns]

@t,
Is this circuit using pwm at the power line frequencies? (50/60hz). I was trying to use a PIC with a 20Mhz clock to make the PWM in software timing loops but I was not successful. It is a tapped winding so I have 2 logic level FETS driving the transformer alternately. Do I need to have a low pass filter on each FET to smooth the current to the iron transformer?

thanks
Bruce

 

[@t]

Is this circuit using pwm at the power line frequencies (50/60hz)? // Do I need to have a low pass filter on each FET to smooth the current to the iron transformer?

Hi Bruce,
As far as I know it uses both low (50Hz) and high (20kHz?) PWM to drive the output stages.
Filtering is done here at the secundary (output) side of the transformer, (not connected to the Fet's).
At.

 

[RF_Burns]

I should be able to apply the 20Khz PWM through a FET in the center tap of the winding and switch the 60Hz through the FET on each winding to ground then.

I should be able to simplify the circuitry since there is only one load, I don't need to monitor for current overload or load sense startup etc.

I'm not sure the 20Khz will work with the iron core transformer. I will likely get much less voltage out.

 

[@t]

Bruce:
Yes that sounds ok. Concerning the 20Khz is worth a try, it's not that high.
Are you going to modify this (C code) software, or do you have your own?
At.

 

[RF_Burns]

My circuit actually uses a 16F876 to monitor 3 Microchip temperature sensors within the refrigerator and along with monitoring the supply DC voltage, displays them on a LCD. This PIC also sends an On/Off control to a 8 pin PIC (12F620 i believe) which generates the 60Hz switching to the transformer windings using timing loops.

It is written in CCS C as well. I am not a profession C coder, so I didn't know how to use the PWM function. My code is very simple, turn a pin ON, Delay_us(), Turn pin Off etc. I had tried using the 16F PIC to do everything, but the code to load the LCD would not allow me to try to do PWM switching using software loops so I gave that job to a 8pin PIC that only switched the FETS.

I used logic level FETS in an attempt to reduce parts count, but they do get quite warm on a large heat sink just switching a 60Hz square wave, so I may have to increase the gate voltage to reduce the On resistance.

I once got a reasonable sine wave from the transformer output, but the FETS got extremely hot quickly and I was leaving for a vacation with the Motorhome, so I made it into a "modified sine wave" (square wave with delay between) so I could use the refrigerator. It works Ok, but I would like to improve it.

Thanks
Bruce

 

[@t]

Hi Bruce, nice fridge project.
I had one working on gas earlier, worked without sinewaves for 15 years, now I've got a 12v one, also without sine, on DC..
I am experimenting with small solarpanels on my motorhome and am looking at generating 230v 50Hz from that (sinewave with Pic's).

If you got a sinewave (earlier) by filtering before the FET gates, they started to work in analog mode (I suppose) and really got hot as an audio amplifier for 60Hz.
Did you (later) try a bootstrap circuit, to get higher gate drive voltage, in modified sw mode?

Greetings, At.

 

[ronyintel]

HI
i am vary new to this forum. I have got 16f72 pure sine wave inverter asm code and hex. i made it and its working fine. Now i am following Mr. Tener's project. I need a simple help that is how to correct output voltage with feedback. i have studied Tener,s code but i cant Explore Closed Loop Algorithm. Can anybody Help to Find this. Then i can complete the project and share it to the forum.

 

[xaccto]

Hi Tanner

I must thank you for sharing your inverter project, i've been following this
thread for a time, now i'm thinking of making an inverter too!

can I ask why you chose primary winding of main Transformer as single winding ?
seems center tapped transformer is equally available and so would require 2 few switches
driving the transformer.


How much free code space is left in your implementation using 16f876 ? and and
how max'ed is the performance of the code ?
I'm asking this because my aim would be to experiment with grid-tie ability, so I might
need a faster PIC, maybe dsPIC ?

I'm going to use 24V, and want ~600VA rated transformer (still looking for an appropriate Tx, yes its not expected to be cheap, and toroidal is best also?

Another question regarding the design by Tanner, the Tx is indicated 8VAC/230AC,

so to operate at 24V is it good enough to assume Tx of (8/12)x24=16VAC/230VAC

or what rule of thumb is being used here ?

anything to do with,say 12V Batt, useful voltage down to 10V, so assuming maybe 2V losses in primary, allows Tx N1::N2 for 230VAC operation ?



Thanks

 

[xaccto]

Another question regarding the design by Tanner, the Tx is indicated 8VAC/230AC,

so to operate at 24V is it good enough to assume Tx of (8/12)x24=16VAC/230VAC

or what rule of thumb is being used here ?

anything to do with,say 12V Batt, useful voltage down to 10V, so assuming maybe 2V losses in primary, allows Tx N1::N2 for 230VAC operation ?



Thanks

 

[socio74]

Hi everybody.

I've been reading this interesting post because I'm looking for an inverter 230V AC 50Hz without harmonic distortion from 150Hz to 1.5kHz (3rd to 30th harmonic).

I cannot see comments about the performance of this design, and I think it's a very good design.
Has anybody tested its performance? Could anybody attach a Fourier Analysis?

Thanks in advance.

 

[@t]

.. // . Has anybody tested its performance?

I have the idea that not much people have succesfully build and used this project.
Although Taner says he does, but he doesn't respond much. I think the original design is from ASP in Switzerland.
www.asp-ap.com

--- edit
There has changed something around the website of asp, or with the company itself maybe. The link is from a document dated 2003.
At

 

[MRahman]

Hi Rony,
Thanks and congratulation for your great achievement on Pic16F72 sine wave inverter. Would you be brave enough to share your hard work and experiences with us on this forum, may be start with PCB side then much more, because till today this forum appears to me (Right of free speech) some kind of advertisement forum, lot of big talk, leads to other forum, perhaps no one got yet a single complete project to be done. Please be Royal Bangle Tiger, not a Monkey.

May all mighty bless you,
Mohamad

 

[daniello_85]

Hello Taner

A big project. I've a question. Could you tell me what's model of current transformer?
And the inverter transformer is toroidal? The sine wave is pure sine wave?Thank you very much

It's a big project.
Greetings

 

[daniello_85]

Hello Taner. I'm doing this proyect sine-wave inverter with PIC16F876A.

I've a problem. If I use a transformer 200VA, I'm going to change the current transformer and to change the code of program???To modify the current_l and current_h, no??

I'm very interested in this project! The best!! Greetings