Voltage sensing

[ericgibbs]

Dear Ericgibbs,

Thanks for your reply..

Yes,am planning to do the zero crossing detection...but,i dn't how to sense the +ve and -ve half cycle ..kindly help me with circuit if you have

hi samson,

Look at this image, the +5V Vzcd is positive for mains positive half cycle.

Which type of MCU are you using.?

 

[samson.bunty1986]

Dear Ericgibbs,

Am planning to use any of the PIC16F family..

As you suggested , Can i use two optoisolators and two diodes for positive as well as negative output reference?? Just like your circuit,in positive 5V ref will get. And in negative cycle also from second optoisolator we will get 5V..is it possible to have such a type of circuit??

 

[samson.bunty1986]

Dear Ericgibbs,

Here am having doubt..please clarify...by using this circuit we can get +5V when the mains in positive half cycle. So, will the micro-controller have to know if +5V Vzd gets then mains is in positive half cycle if we din't get +5V it is in negative half cycle...is it???

 

[ericgibbs]

hi,
I would like to help but I am finding it difficult to follow what you are trying to do.

You say you have a existing battery charger, it will have its own fullwave bridge rectifier so the output to the battery will be DC.

Why do you need to control MOSFETs on the positive and negative half cycles.???

If you give me an idea of the purpose of switching the MOSFET's or post the circuit I will help.

Usually zero crossing detection is for switching AC circuits for phase power control.?

E.

 

[samson.bunty1986]

View attachment 64410

Dear Ericgibbs,

Please go through this circuit...Am planning to do this type of charger...I need your help for this..For clear understanding kindly go through the datasheet of "A Novel Economical Single stage battery charger with power factor correction" from web..

 

[ericgibbs]

View attachment 64410

Dear Ericgibbs,

Please go through this circuit...Am planning to do this type of charger...I need your help for this..For clear understanding kindly go through the datasheet of "A Novel Economical Single stage battery charger with power factor correction" from web..

hi,
This signal from the RCD filter gives the same output as my earlier circuit.

Do you intend writing your coding for this project.?

E

 

[samson.bunty1986]

Dear Ericgibbs,

Yes your earlier circuit is just like that RCD filter circuit. Is this circuit is for zero crossing detection?? Or it is for ontaing unity power factor??How can we identify the mains cycles(+Ve & -Ve) ,to operate the both lower mosfets?? how to code for this?? Kindly support me...

 

[ericgibbs]

Dear Ericgibbs,

Yes your earlier circuit is just like that RCD filter circuit. Is this circuit is for zero crossing detection?? Or it is for ontaing unity power factor??How can we identify the mains cycles(+Ve & -Ve) ,to operate the both lower mosfets?? how to code for this?? Kindly support me...

hi,
In the text shown in Fig3 from the datasheet it states its for to obtain unity gain power factor.

Do you intend writing the PIC program for this project.?

What power rating will your charger have.??

EDIT:
Do you have the L4981 IC.??

 

[samson.bunty1986]

Dear Ericgibbs,

My battery is 24V,45AH,SLA battery(Two 12V,45AH in series connected).. Each battery had an initial current upto 13.5A. I dont know how in this circuit they have controlled the current here..but i wish to have the current control to 7A because my transformer rating is 240VA(24V,10A). So can we do it with changing the pulse width of Lower mosfets for charging current 7A max?? My charging voltage will be 30V appx...The circuit works like boost circuit it seems..

 

[ericgibbs]

Do you intend writing the PIC program for this project.?

Do you have the L4981 IC.??

 

[samson.bunty1986]

Dear Ericgibbs,

Am purely into hardware..so i dont know to write program..can you support me??

Right now i dont have L4981B IC...I will get it soon...

 

[ericgibbs]

Dear Ericgibbs,

Am purely into hardware..so i dont know to write program..can you support me??

Right now i dont have L4981B IC...I will get it soon...

hi,
The report paper for the project shows that its was only taken the experimental stage and more work would be needed.

I do not have the free time to get involved in writing a complex program, especially as I would not have any supporting hardware on which to debug the program.

Many thanks for your request in asking me to help, but at this time it would not be possible to help with programming, good luck with the project.

Eric.

 

[samson.bunty1986]

Dear Ericgibbs,

Thank you for your support till now...You really helped me to know new concepts... I will try to do this project as early as possible and let you know..Thanks once again for your precise time spent for me...