need help with power inverter

[babatundeawe]

huy guys! i am very glad to be in this forum atlast. i ve read so many threads posted by talented people here. i really appreciate them all.

please i need help on how to construct an inverter using pic16f877a 50hz pwm with an input of 12v an output of 260v 2000kva. please anybody that can help will be highly appreciated.
my main problem is to generate the pwm 50hz from the micro.schematic and source code (asm or pbp) will do along way to help me. thanks in anticipation

[babalola]

Hi awe,

Are you realy talking about 2000KVA or you mean to say 2KVA?.

Regards,
babalola.

[babatundeawe]

Hi awe,

Are you realy talking about 2000KVA or you mean to say 2KVA?.

Regards,
babalola.

thanks. its a mistake i mean 2kva.

[babalola]

Hi Awe,

Honestly you need to start yourself from somewhere, however i can help with block diagram,but hang on while i try to do that.

Babalola.

[mikeh]

first forget 12 volt current to high 166 amps
for 2kv 48 or 60 volts
i am busy with a inverter at the moment
what you need is 64 steps 32 first half and 32 second half
using ccp1 and ccp2
can supply you basic wave form numbers
you need voltage check amp check tx loss control all done in loop
i use a full h bridge driver to give pure sine wave
mosfet driven.
the pic is quite busy use 20mhz
this is just basic
hope it helps

[Andre_Pretorius]

Hi there seems if this can become very interesting, is there any change of see-ing the H-bridge circuit for the 2Kva inverter

[mikeh]

i use the hip 4080
i would use igbt for 2kv or a lot of mosfets
you need to use low on resistance type
the 18f2550 has h bridge but have not tried it

[sudipmuk]

what you need is 64 steps 32 first half and 32 second half
using ccp1 and ccp2
hope it helps

Hi
I have seen PCBs of sinewave inverter using 16F72. They do not have CCP1 and CCP2 , they only have CCP1 . I wonder how they have done it.

Regards
Sudip

[mikeh]

As Far As I Know A Full Bridge Is Sine Wave Less Is Mod. Square Wave
Maybe Some Trick Components.
Or Using The One Ccp To Gen. Freq. Like You Can Do With A 555

[sudipmuk]

As Far As I Know A Full Bridge Is Sine Wave Less Is Mod. Square Wave
Maybe Some Trick Components.
Or Using The One Ccp To Gen. Freq. Like You Can Do With A 555

These PCBs are using a full H- Bridge , and the output is a pure sinewave . I have seen the output in an oscilloscope. Four pins of the PIC are being used to drive the mosfets.

[babalola]

hi guys,
the technique of using the single ccp on 16f72 is to generate additional square wave called switcher to modulate the sine pwm of the controller, the switcher wave is of the same frequency with the sine pwm wave.this will eventually give the two leg sine signal that can power the h-bridge output.if am less busy i will post a basic schematic of the steering circuits.

regards,
babalola.

[sudipmuk]

Hi
I know about steering circuits and i can make one myself too . But i was telling about these PCB s that they do not have a steering circuits. The four waves needed for the H Bridge is coming from 16F72 . And they have used RC2, RC3, RC5 and RC6.
Any idea how they are doing it without steering circuits ?

Sudip

[sougata]

Hi All,

A compare module can generate software PWM effectively with low ins.cyl overhead. The stearing is all done in software.


You turn on the pin (according to the steer logic) and with compare interrupt turn off all the outputs. Comapre value comes in from the PID. Turning off the outputs in the ISR and turning them on (sterring) gives you the dead-time automatically. It is not that complicated.

Sorry can't share the code. (Mostly ASM)