Adaptable 12vDC/220vAC Pure Sinewave Inverter

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Intro: Adaptable 12vDC/220vAC Pure Sinewave Inverter

Here is a very simple pure sinewave inverter based on the microntoller "PIC 16F628A", "don't freak out !", NO it is not difficult to use microntollers, actually it could not be any easier than this.

For those wondering, Yes I myself designed the circuit concept, schematic and components but had to hire a programmer to write the code since I have no idea how to write software programming, I even paid him money to do this job since no one works for free these days, probably if he see this instructable he would be laughing at me on how I gave everything for free here :-/

The principal used for creating the sinewave:
Most hard work in this circuit is done by the 16F628A chip itself, where it divides the half wave into small segments generating PWM train of pulses to create each half wave as shown in the pic, generated oscillation then go to get amplified by the 4 transistors Q1,Q2,Q3 and Q4 where they feed the power stage to drive the power transistors. Can't be much simpler than that !

There are 2 options to program the 16F628A:
1- Most of the electronic parts selling shops do this service for you for an additional 3$ cost, where you take the program which is a "Inverter.HEX" file in our case, written on a disk to the shop and they will hand you an already programed 16F628A.

2- If you're an electronic hobbiest I suggest you buy your own programing device (I bought mine for 22$) and experiment with it because the microcontroller applications that can be built are endless. I bought the cheapest / smallest USB one which is a DIY K128 it came along with a CD containing the MicroBurn software "older versions known as MicroPro" and a driver for your computer, after setting up the driver and operating the thing, it programed the 16F628A IC in 10 seconds !
Here is a link to see how the programmer looks like.

Note: Both 16F628 and 16F628A will work, the difference is that the 'A' has more memory capacity, but both work the same.

The filter:
The 2.2 uF capacitor which is the filter is a very very important part of this design, without it you'll never get a pure sine wave.
I have included 2 screen shots of the oscilloscope (with-filter and without-filter) so you can see the difference and importance of this capacitor.

Other notes:
- Included is the movie file "IMG_0690.MOV" in case you encounter any problem and need to see the wave form on pins 11 and 12 of the 16F628A how it looks like.

- The PIC16F628A is so sesitive to static, if you're sitting on a plastic chair never touch the IC's pins with your hand.

- You can build bigger versions of this inverter up to 5000w, to see what needs to be done on the power stage please see details on my other instructable here

- Heat sinks are required to cool the power transistors they should be big enough to cool the transistors, they are separate and should NOT touch each other.

- Wiring connections marked in dark black on the power stage section should be thick enough to handle the big amps drain from the batteries.

- A cooling fan will be needed to reduce heat off the heat sinks and transformer.

- Be cautious when building this circuit it involves high voltage which is lethal, any part you touch when the circuit is ON could give you a nasty painful jolt, specially the heat-sinks, never touch them when the circuit is on to see if the transistors are hot.

Finaly:
Do not forget to rate this instructbale with 5 stars "of course if you like it and appreciate the effort done" and also click the "follow me" button to keep updated of future instructables and updates that I do.

We need to get this inverter to perfection by adding some more options to it like:
- Low DC Battery voltage detection to trigger a buzzer and a to auto-stop oscillation at some point.
- Heat detection to trigger a fan ON
- Battery level indicator 3 LEDs (High-Medium-Low) and to trigger charger ON
We'll need some help to code the above..
so any suggestions, help in coding or design on this project to make it better are very welcomed so send your thoughts.

537 Comments

is it possible to see source code for uC ?
hey nick I'm building this for an open source EV and I wanted to know is there a way to change the frequency of the sinewave so that the engine rpm changes. thanks btw you really helped us out.
One year passed and the movie download is still invalid.
Thanks for sharing this information
I really want to know who really built this project and not simulation
I also what to know if the voltage is a regulated 230 volts if possible share a video via utube
Thanks

Hey, can someone tell me at which pin of mictrocontroller, does the pwm wave will appear?

I followed your circuit diagram and even I used your hex file for construction of my inverter.can you please tell me where I can connect CRO probes to get the wave forms..
hola buenas a todos me podrian pasar el archivo en proteus a mi correo eliasvedia14@gmail.com exelente aporte muchas gracias un abrazo desde argentina
copy permission, thank you..
Hi sir, can i ask how to adjust into 60hz? because the system in here philippines is 60hz, what should i do?
Hi. The movie download link is invalid. Please repair it.
Hey, can someone send me the main .asm program of the hex. File
This is my email sidi2019@gmail.com
Good day, can I please ask on the size or part number of the transformer that you can use like on the 5000w inverter
Hi. How do I adjust your diagram to make it a 110 volt ?. Thanks
have any one connect a load in this circuit. I have doubt when i connect the load the waveform shape is get changed. and also output voltage get varied when i connect the load across transformer. Circuit is tested on proteus. Please help
Hi Mr Nick please can u send me this code to enable me construct and make it work through your help. i am interested in doing it with your help by sending me the code.
Thanks for your effort by en lighting us with more in your great works................
here is my email address zealthehightech@yahoo.co.uk
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