Inverter, IGBT, Optocoupler, PIC

[samuel yap]

I am constructing a single phase inverter which consisting of 4 IGBTs. Each IGBT is controlled by optocoupler (gate drive).

It is a full bridge inverter. The four IGBTs is named S1,S2,S3,S4. During positive cycle, S1 and S4 switched on and S2 and S3 switched off. During negative cycle, switch S2 and S3 switched on and S1 and S4 switched off.

I need to set a pwm on the switching of each IGBT. Who can help in term of idea and its code?

[asmboy]

you should understand that this forum is about CCS code specifics

it is
not a place to get your student homework done
or to have somebody design your circuit and write your code.


you need to show some initiative and only ask specific questions about your circuit and the CODE you wrote

[Mike Walne]

Give us some idea of:-

(1) Input voltage.
(2) Output voltage.
(3) Output power / current.
(4) AC or DC output.
(5) Regulation.
(6) Protection.
(7) Switching frequency.
(8) Response to load change.
(9) Your power handling experience.

Mike

[temtronic]

Plus we'll need to know
1) PIC processor
2) Compiler version
3) your level of CCS C compiler experience

[bkamen]

You want a PIC with an ECCP module that handles full-bridge PWM in hardware.

That's all I have to add.

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[Mike Walne]

I'm with the other guys on this one. YOU will have to do some work first.

If you want "ready made solutions" try google, we are NOT going to do it for you.

Mike

[bkamen]

[samuel yap]

I don't need "ready made solutions". What i need is the procedure and guideline. I have some questions:
1. What is the difference between postscale and prescale?
2. Is that I need to set 2 types of pwm mode? One is for S1 and S4. Another is for S2 and S3.
3. Is pic18f4550 suitable for pwm module in my case?

[bkamen]

[Mike Walne]

You've got a lot of reading to do. You need:-

(1) The microchip data sheet for your chosen part. Tells what hardware is available and all its modes eg PWM, prescaler, etc.
(2) The CCS manual. Gives the syntax for setting up, and writing / reading the registers for the hardware in a generic fashion.
(3) The CCS .h file for your PIC. Gives the syntax for the specific registers on that chip.

You need ALL the above. CCS is not totally consistant with its syntax across the PIC range. For example setup_timer_x() has an underscore before the x, set_timerx get_timerx do not ! It's the sort of thing that throws me. I find it frustrating that I have to regularly look up that kind of thing.

Oh and (4) Maybe a good 'C' manual. Depends on your experience, try K&R.

You've still not answered most of the questons that others and I asked (they're ALL pertinent).

Mike

[samuel yap]

(1) Input voltage. 170Vdc
(2) Output voltage. 120Vac
(3) Output power / current. 500W, 4Aac
(4) AC or DC output. AC output
(5) Regulation. NO
(6) Protection. NO
(7) Switching frequency. I have no idea, can you suggest to me ?
(8) Response to load change. NO
(9) Your power handling experience. NO

[samuel yap]

(1) Input voltage. 170Vdc
(2) Output voltage. 120Vac
(3) Output power / current. 500W, 4Aac
(4) AC or DC output. AC output
(5) Regulation. NO
(6) Protection. NO
(7) Switching frequency. I have no idea, can you suggest to me ?
(8) Response to load change. NO
(9) Your power handling experience. NO

[samuel yap]

Please refer to my original topic description


1. Prescale is a divider before the counter clock input, postscale is a divider after the counter output.

2. This sentence is incoherent, can you please try again?

3. Does it have an ECCP? Yes. You probably want to use the QUAD PWM mode.

-Ben[/quote]

[bkamen]

[asmboy]

based on the critical number of "RED NO"s - i honestly think that this is a project that is WAY beyond what you are ready to undertake.

what you need is an engineer, with power experience to do this for you.

otherwise , i believe smoke , flames and salty tears are in your future.