Sine wave power inverter

[sougata]

Hi,

I do not produce inverters commercially. I only developed the firmware. With the newer PICs having better peripherals design is even easier.

[babalola]

Hi Sougata,

Its a long time to hear from you.
To do voltage feedback on the output of inverter with PI routine, is it better done within the main interrupt scheme where the duty cycle is updated or within the background loop and why?.
Iwanted to try the followings for my digital PI control of the inverter output: If my error is negative
U(k+1) = -U(k)+ A*e(k) - B* e(k+1)
If error is positive,
U(k+1) = U(k)- A*e(k) + B*e(k+1), Does the above make meaning?

Can any one advice,

Babalola.

[sougata]

Hi,

With a quick look, I couldn't make anything out of the formula. Explain in details about U seems to be the desired voltage, K constant, e error, what about A and B. Are they the P and I .

How are you tuning k ?

Post Code.

[samrulezzz]

hi Sougata

Actly its like i'm a final engineering student.....n inverter is ma project for final sem.....i ve a hardware design fot inverter....n also interfacing circuits....which actly i got frm my guide...

but now problem is no1 around knows PIC properly to write a accurate program.....


so I was hoping if u could help me on some coding of PIC16f72 to be done.....Particularly PIC16f72 cuz the i ve the design ready for it.....


can u help me to write a code....or if u cuold give some old code (i.e of PIC16f72 inverter code) u have so that it wud help.....

sam
[email protected]

[sougata]

Hi,

To help you with the software flow the schematic is needed. Wondering how you rigged up a schematic without having fully understood the programming philosophy and the 16F72 !!!!!!!!!!!

[babalola]

Hi Das,

The e(k+1) is the present error
e(k) > past error
u(k+1)> present output of the pi controller
u(k) > past output of the controller
the above are digital parameters of the pi controller and in the course of getting these parameter there is alway need for sampling time (T), the propotional gain of the controller Kp and the zero placement of the controller which is WI
INTERGRAL GAIN KI=Kp*WI
therefore A=Kp(WI*T -1)
while B=Kp

Example if kp=0.04 and WI =3140rad/sec SAMPLING TIME OF 10us

KI=188.4
A=0.04(3140*10US-1)
B=0.04

Remember in PI controller proportional looks at present error while intergral looks at past errors

Regards,
babalola.

[picgak]

Hi sougatha and Thank you,
I have been a regular visitor to the Thread sine wave power inverter for a long
time. I am happy to get a reply for my first query from one of the experienced hands. My
knowledge of PIC programming is minimal. I got the inspiration to do this project for my
home from here. Can you kindly suggest me a link to learn PICBASIC commands in some detail.

[babalola]

Hi Das,

The e(k+1) is the present error
e(k) > past error
u(k+1)> present output of the pi controller
u(k) > past output of the controller
the above are digital parameters of the pi controller and in the course of getting these parameter there is alway need for sampling time (T), the propotional gain of the controller Kp and the zero placement of the controller which is WI
INTERGRAL GAIN KI=Kp*WI
therefore A=Kp(WI*T -1)
while B=Kp

Example if kp=0.04 and WI =3140rad/sec SAMPLING TIME OF 10us

KI=188.4
A=0.04(3140*10US-1)
B=0.04

Remember in PI controller proportional looks at present error while intergral looks at past errors

Regards,
babalola.

[samrulezzz]

hi Sougata


Actly my guide provided me with the circuits....

Ive attached few interfacing circuits....
hope this is wot u requested....

[picgak]

hi
I want to make a sine wave inverter with 310 vdc H bridge as the final stage driven by signal from sine tabled PWM from PIC microcontroler. can anybody suggest me a cheap and best controller from the pic family.

[sougata]

Hi,
A PIC16F616 could be a good choice or even better a PIC16F1824 The later runs at 32MHz has ECCP and supports linear addressing and shadow registers for fast interrupt return.
Since you would be having a High Voltage DC Bus it is easy to keep it regulated / overcurrent protected and simply drive the output bridge using a micro though a sine table. The only complication could be isolation between the battery boost and the output stage if the same micro is used for housekeeping too.

P.S. - Personally I would have selected a PIC18F1330.