Generation of Pulse in LTspice

Thread Starter

mohtishamali

Joined Jul 9, 2021
55
Good day,
I want to generate this pulse in LTspice but i am unable to do so. Could anyone here please guide how can i generate that in LTspice.
Thanks in advance
1670428220572.png
 

WBahn

Joined Mar 31, 2012
27,854
The first thing is to model the pulse mathematically. It looks like it might be essentially two exponentials, but you probably need to do something to a smooth transition at the peak.
 

Thread Starter

mohtishamali

Joined Jul 9, 2021
55
The first thing is to model the pulse mathematically. It looks like it might be essentially two exponentials, but you probably need to do something to a smooth transition at the peak.
Actually that is what i am struggling to do. any suggestions please
 

Thread Starter

mohtishamali

Joined Jul 9, 2021
55
hi mo,
This is the method, shown a close result, up to you now to finalise.
E
View attachment 282475
Thank You for sharing.
Actually i was using ISO7637-2 pulse which you can find in LTSPICE libray. That pulse is exatly what i want but i am unable to modify it exactly as per my requirement. Could you please also have a look at that and advise what could be modified there
Thanks
 

ericgibbs

Joined Jan 29, 2010
16,748
hi mo,
Have you generated an asy file from the cir file, also do you have asc file with a plot that you could post.

BTW: using the EXP option, I have created a pulse that is in within approx 2-3% of the ideal pulse.
E
EG57_ 337.png
 

ericgibbs

Joined Jan 29, 2010
16,748
hi
Thank you for the lib file, but you have already posted the cir file, from which I have created a model for the basic pulse asy.
Post your versions of the asy and asc files.

E

Example clip from the web of an asc file and model.

EG57_ 340.png
 
Last edited:

ericgibbs

Joined Jan 29, 2010
16,748
hi mo,
As this is a Homework or College assignment, I want to see your best attempt at solving the problem, then I can help.
E
 

Thread Starter

mohtishamali

Joined Jul 9, 2021
55
Good day,

Can anyone please guide how can I simulate fault analysis in LTspice. I want to introduced a load transient but i am unable to find any suitable block for that in LTspice Library. ususlly in matlab/simulink and in pspice i jnow there are fault generation blocks but nothing i found here in LTSpice. Will wait for your kind response.
Thanks
 

ericgibbs

Joined Jan 29, 2010
16,748
hi mo,
Your LTSpice asc does not work, I have to make some changes
I would like to see your best effort in solving this problem, do you have a copy of the complete original assignment.?
E
EG57_ 366.png
 

Thread Starter

mohtishamali

Joined Jul 9, 2021
55
hi mo,
Your LTSpice asc does not work, I have to make some changes
I would like to see your best effort in solving this problem, do you have a copy of the complete original assignment.?
E
View attachment 282875
Its working for me and everything what i want with regards to input filtering is there. I just want to add a load transient pulse at Vbus+ and Vbus-. If u could pls only guide me about that how can i add it. here is my simulation. green is input dc bus voltagr and blue is voltage at switching node
 

Attachments

Papabravo

Joined Feb 24, 2006
19,558
Put two voltage sources in series. Use the "delay" parameter in the pulse source to create an input transient. Put a current source in series with your load and use the "delay" parameter to introduce a load transient. Alternatively, use a voltage-controlled switch to short out a portion of your load. Many ways to accomplish that goal. Use a current source as a load with a triangle function to make a continuously changing load.
 
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