3 phase fully controlled converter

[RishabhG]

I am trying to simulate a three phase fully controlled converter circuit but I am not getting the desired output.

here is the circuit

https://obrazki.elektroda.pl/4785965500_1352553387.png

The output that i should obtain is this

https://obrazki.elektroda.pl/5084599200_1352553566.png

can anyone help me select the right values for pulse generator's phase delay in seconds?

 

[BradtheRad]

Phase delay is typically in degrees. It's a lot of trouble to figure it in seconds (milli-seconds).

Can you bring up an edit window for the AC Pulse source, containing parameters similar to this screenshot?



I believe you'll enter a different amount for all six pulses. In increments of 60 degrees. Positive means advance. Negative means delay.

Duty cycle will be 25 percent, going by the look of your waveforms.

 

[RishabhG]

Here it is

https://obrazki.elektroda.pl/5723647700_1352620201.png

 

[FvM]

Your power circuit seems to be wrong. The lower SCRs are shorting the input power. The star point should be floating.

 

[BradtheRad]

It appears you will have six pulse generators. You must adjust each one. Each will have the same period and duty cycle. But each will have a different delay.

The period is correct at 50 Hz.

--------------------------

Phase delay:

The first generator will have 0.

You want the second one to occur 1/6 of a cycle later, or 1/300 sec. So type in -.0033 sec.

In the simulator I use, it interprets a negative value as a delay. You must try both positive and negative values to make sure which works the way you want.

Then go to the next generator and type in -.0067.
The next -.01.
The next -.013.
The last one will be -.0167.

If you find they are not staggered correctly, then you may need to reverse the sequence, or change all signs to positive, or both.

------------------------

Perhaps I was wrong about duty cycle. Looking at the bottom timing chart, a pulse lasts another 1/3 of a division past 60 degrees. Around 80 degrees, or 22 percent.

However I notice that the upper timing chart is scaled differently, and that chart makes it seem as though Alpha should be 90 degrees, or 25 percent duty cycle.

You will have to try both figures. Or get advice from someone more knowledgeable.

 

[RishabhG]

I need the firing angle to be 60 deg.

 

[BradtheRad]

I need the firing angle to be 60 deg.

If you mean duty cycle then this looks as though it works out to 60 out of 360, or 16.7 percent.

To make sure things are going right, you'll need to see scope traces of all pulses, stacked on top of one another... just like in your diagram #2 in your post #1. I don't know how easy that will be.

By the way, FvM's reply is most likely correct.