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I started working on a single series lithium to 15V / 2A Boost converter
based on this design: .
I got this PSpice simulation model from TI themselves here:

After changing the file so that it works like described here:
,
I then got a simulation working:
[![Schematic of working spice simulation][1]][1]
?
Then, after saving everything and doing something else on my computer I
returned to the project and now the results make no sense anymore:
[![Output node of not wokring SMPS][2]][2]
(output of the converter)
[![enter image description here][3]][3]
(switching node of the converter)
[![enter image description here][4]][4]
(EN node of the TPS43061 (has to stay over 1.14V ?!)
?
Where do these weird transients come from? I don't remember changing any
simulation parameters, so they must be the standard ones.
Are there some parameters I could change to omit these strange errors?
The design has been proven to work before.
?
Files: !Ai1WNGQ9wFb7g5hYmVUygiMGqTib5w?e=Ww1wg7
?
Schematic of working circuit:
[![Schematic of wokring SMPS][5]][5]
?
maybe someone can even wokr out these errors:
```
Questionable use of curly braces in "b§e_abmgate yint 0
v={if(v(a)>0.5|v(b)>0.5|v(c)>0.5|v(d)>0.5,0,1)} "
? ? Error: undefined symbol in:
"if([v](a)>0.5|v(b)>0.5|v(c)>0.5|v(d)>0.5,0,1)"
```
?
Cheers
?
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On 2/25/21 1:36 PM, Donald H Locker wrote:

Again, increasing the supply voltage (the V source labelled VHV near the
top right of the schematic; it is set to 24V) will increase the motor
speed (and, consequently, the commutation frequency.)

Changing it to 12V will slow the motor to about half speed; increasing
it to 48V will approximately double the motor speed.

It is a brushless DC motor - speed is controlled primarily by the supply
voltage. Commutation frequency is a function of speed; speed is NOT a
function of commutation frequency. The way to change speed is to change
the supply voltage; commutation frequency will then also change.

Did I mention to change the supply voltage (change it from 24V) to
change the motor's speed?

Donald.

Actually, you CAN control speed with commutation frequency, but only
downwards, if you disengage that automatic commutation system normally
being used, you can get very tight speed control by using a fixed
frequency commutation. You do need to monitor the speed the motor is
going because if something does cause it to drop you may need to adjust
the commutation to keep it from loosing lock.

I think that your question concerning "Documents\LTspiceXVII\lib
directory tree on your C:\ drive" is the key. For some reason it
wanted to use D:\Onedrive\documents, which wasn't there. I added the
drive and folder, and now it launches. I have some work to do to find
out more about why this is happening, but at least I have some idea of
the problem.

Hi Gents,

Thanks for your comments,

Initially, my thought was motor will spin faster by changing commutation
frequency. Anyways, I have managed to change motor speed by increasing
input voltage as it is function of Back EMF.?

Appreciate for your comments.?


Kind Regards,
Jayal Pansuriya

On Tue, 23 Feb 2021 at 23:51, Vlad <imbvlad@...
<mailto:imbvlad@...>> wrote:

Hello Jayal

> I am have intermediate skill for simulation, just trying to
simulation BLDC
> motor from LTwiki example(
> http://ltwiki.org/files/LTspiceIV/examples/Motors\MotorTest01
<>).
I managed to
> simulation with default parameters but not sure, if I can change
speed or
> commutation frequency.

The speed of the simulation is given (mostly) by the models. As for
the parameters, they are there, as long as you know what you're
changing, nobody is stopping you from testing.

--
Vlad