Need urgent help for simulation of 3 pulse three phase to single phase cycloconverter

[mehtarock026]

i am doing cycloconverter (STEP DOWN) project.. i need urgent help for "simulation of 3 pulse three phase to single phase cycloconverter" either in matlab or multisim... and i want to know how to do 60 degree phase shift for 3 phase input in matlab...??? if anyone knows anything about this then please reply asap...

 

[goldsmith]

Dear mehtarock
Hi
I can help you with Pspice . can this program solve your problem ?
Best Wishes
Goldsmith

 

[mehtarock026]

Dear goldsmith,
hi... first i would like to say thank you very much for your prompt reply.. In which way you can help me by directly providing simulation or any other way? because i have to show simulation only in matlab or multisim... but if you can give me simulation in pspice then i can easily implement that thing in multisim..

 

[goldsmith]

Yes , i can simulate it at Pspice

 

[mehtarock026]

then mail it to me @ mehtarock026@yahoo.com

 

[goldsmith]

Hi again , but what kind of cyclo converter do you want to simulate exactly ? have you any schematic of that ?
Respect
Goldsmith

 

[mehtarock026]

Hi again , but what kind of cyclo converter do you want to simulate exactly ? have you any schematic of that ?
Respect
Goldsmith

yes i have but its OK because i have done this in matlab... But thank you very much for helping.. i wanted to simulate 3 pulse 3 phase to single phase cycloconverter..
i am actually making project for the same... But i have to do hardware implementation along with simulation.. Now i have done simulation but facing problem with hardware..

 

[goldsmith]

Hi again
Where is your problem with hardware exactly ?
Best Lucks
Goldsmith

 

[mehtarock026]

Hi again
Where is your problem with hardware exactly ?
Best Lucks
Goldsmith

I am using microcontroller to fire SCRs... But I don't know why microcontroller can't fire them properly and hence i didn't get desired output..

 

[goldsmith]

Hi again .
As you know the out put of your microcontroller will be about 5 volts . and it isn't enough to fire a thyristor . and the out put current of your micro ( max=40ma ) isn't enough .
So , you can use a simple optocoupler to driver your thyristor as well as , but not , usual optocoupler ! opto triac or opto thyristor . e.g MOC3021 .
Then your micro will fire opto triac and then this opto triac can fire your thyristor pretty simple .
Best Wishes
Goldsmith

 

[mehtarock026]

i am already using MCT2E optocoupler...???? but still facing a problem...

 

[goldsmith]

Dear mehtarock026
Hi
Can you show me your schematic , please ? by the way , did you test it in practice ? ( i suspected that you tried simulation !!)
Best Wishes
Goldsmith

 

[mehtarock026]

Dear goldsmith,
I have already tested it.. In fact actually i have missed my deadline... but i have been given some more time to complete it.. I can show you my schematic.. Which schematic do you want see..??? I mean i have prepared it with 2 ways... 1) analog firing circuit and 2) digital i.e. using microcontroller.. While working with analog circuit, i have realized that its very tough to implement total analog circuit.. someday getting expected output and the very next day totally distorted output.. So finally decided to fire SCRS using microcontroller.. But still facing problem.. Here i have attached my schemetic.. I have used op-amp for zero crossing detection... While running the project, I didn't even get pulse on microcontroller pins.. So how i can expect cycloconverter output..???

 

[goldsmith]

Dear mehtarock026
Hi
I think your circuit has some problems . are you familiar with float ground ? your 12 volt should be isolated from 5 volt section ( it's ground ) and you should use 2 power supply with 12 volt and separate grounds ! for example if you have supply number 1 , and supply number two , the ground of supply number one should connect to the cathode of thy1 and thy2 and thy3 . and ground of supply number two should be connected to the cathode of thy4 and thy 5 and thy6 .
by the way , there is another way , that called driving with pulse transformers ( the small transformers that designed for this aim , but you'll have some problem with them , and you'd better to use optocoupler and two separate ground . ( you can achieve these supplies from two independent transformers ( 300ma is enough ) or a transformer with three independent windings . first one primary and another : 2 independent secondary .
Best Wishes
Goldsmith

 

[mehtarock026]

Dear goldsmith,
i am familiar with those things... i have already taken care of all those things.. but for simplicity, i have shown that way.. but still don't get desired output...

 

[goldsmith]

Hi again
How you saying that you did that ? look at your attachment , again , ( the arrangement of thyristors ! ) did you created float ground really ?
Best Wishes
Goldsmith

 

[palash1990]

Hey, Do you have Matlab simulation of the above schematic attached? its urgent....