On Tue, May 6, 2025 at 05:14 PM, <arhamishtiaq42@...> wrote:
Sorry, I uploaded the wrong file earlier
Good to know.
My desired output is 150?V, and I’ve noticed that changing the transformer inductances is affecting the output voltage.
As it must.
Currently, if I set the transformer values as L1 = 110??H, L2 = 250??H, and L3 = 1??H, the primary-side current becomes too high.
How much is "too much"?
Since I’m designing a 500?W Dual Active Bridge (DAB) converter, I expect the primary current to be around 8?A, because
I'm supplying 500?W at 100?V input:
So therefore it provides less than 500 W to the load, right?
Iavg=P/Vin=500/100=5 A
IRMS?≈1.3×Iavg?=6.5–8?A?but it’s exceeding that.
But some of that current into the primary represents reactive power, not real power.
Also, by “steady state,” I mean that the average current should not be zero
Um, we are not speaking the same thing.? The average current must be zero.? Transformers do not pass DC.
?
Andy
?
|
You get that from the foundry you plan to use
to make your device. LTspice doesn't have that information.
On 2025-05-06 21:52, Tsukuyo via
groups.io wrote:
Hello guys, Does anyone has 90nm CMOS technology text file or
link something like that. Absolutely for LTspice.
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only
If something is true: * as far as we know - it's science *for
certain - it's mathematics *unquestionably - it's religion
|
On Tue, May 6, 2025 at 04:53 PM, Tsukuyo wrote:
Hello guys, Does anyone has 90nm CMOS technology text file or link something like that. Absolutely for LTspice.
They have been discussed here a number of times, including these:
?
?
I would take all of them with a great deal of caution.? Of these four, the last one is newest
?
Andy
?
|
What version allowed the sim to run without
stalling? I am now using 24.1.8, and the sim stalls after a
different number of microseconds , depending on which tweak I
have made to the .ASC.? I don't tweak the Spice settings, like
Gmin and Abstol.? I let it run for minutes and the stall did not
resolve. The expanded netlist shows a huge number of reports of
'simulation tolerance relaxed' between time points that are
small to begin with and eventually appear identical at 17
significant figures. It looks to me that some sort of error
message should appear, rather than the stall just persisting.
On 2025-05-06 21:44, Andy I via
groups.io wrote:
On Tue, May 6, 2025 at 02:08 PM, John Woodgate wrote:
... But the simulation
still stalls without an error message after less than 1
ms.
My simulation did not stall.? It is somewhat slow and I did
not wait 100ms for it to finish, but it never stalled.? That
might be because of different Control Panel settings, or it
might be because of different LTspice versions.? My simulation
had plenty of "Heightened Def Con" warnings, which are not a
good sign.
?
As far as I can see, your
switching waveforms allow each pair of series FETs to be
on together, briefly, which is not good.
That is the short-circuit current (sometimes erroneously
called crowbar current) through the FETs, and can be the cause
of much of their power loss which is where about 130 watts were
lost.? Switching transistor circuits should be designed with
non-overlapping drive signals so that it won't happen.
?
?
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only
If something is true: * as far as we know - it's science *for
certain - it's mathematics *unquestionably - it's religion
|
Hello guys, Does anyone has 90nm CMOS technology text file or link something like that. Absolutely for LTspice.
|
On Tue, May 6, 2025 at 02:08 PM, John Woodgate wrote:
... But the simulation still stalls without an error message after less than 1 ms.
My simulation did not stall.? It is somewhat slow and I did not wait 100ms for it to finish, but it never stalled.? That might be because of different Control Panel settings, or it might be because of different LTspice versions.? My simulation had plenty of "Heightened Def Con" warnings, which are not a good sign.
?
As far as I can see, your switching waveforms allow each pair of series FETs to be on together, briefly, which is not good.
That is the short-circuit current (sometimes erroneously? called crowbar current) through the FETs, and can be the cause of much of their power loss which is where about 130 watts have gone.? Switching transistor circuits should be designed with non-overlapping drive signals so that it won't happen.
?
?
|
On Tue, May 6, 2025 at 01:51 PM, <arhamishtiaq42@...> wrote:
yes I've changed my inductance to 110us, 250us, 1us but current is still high around 40A. and it is steady
Your messages are somewhat confusing.
?
Of course the inductances should be in uH (micro Henrys), not us (micro seconds), but we get the idea.? I may not understand what you meant by "steady".? I'm assuming you did not mean DC, but maybe you mean the steady state RMS current after transients die out.
?
Do we assume that we should start with the schematic named "Dabnew.asc" and change to these values:
- L1 = 110u
- L2 = 250u
- L3 = 1u
and that you see a primary (L1) current of 40 Amp, and you think that is too much?
?
I do not see a current near 40 Amps.? My simulation shows that the primary current is 12.9 Amps RMS.
?
Its waveform is rather peaky (distorted), and the peaks reach around +/- 28 Amps = 56 Amps peak-to-peak.
?
What do you expect the primary (L1) current to be?
?
The primary voltage is a +/-95 V square wave which comes out to 95.6 V RMS.? So the input VA product is 1233 Volt-Amps.? We know its volt-amps but not its power because the phase shift is not known.? If we look at the power source (V9), it supplies an average power of almost 600 watts to the circuit.? Therefore the power going into primary winding L1 must not be greater than 600 watts, even though its VA is 1233 Volt-Amps.
?
The load resistor, R1, dissipates about 460 Watts.? 600 watts in, 460 watts out, so 140 watts is lost somewhere.??You can check for places where energy is lost.? For example, each of the four MOSFETs on the secondary side (M4, M5, M6, and M7) dissipates 32.4 watts, so you lose almost 130 watts in those four transistors.? I'm guessing the losses are a lot smaller in the transistors driving the primary.? But I leave that to you.
?
In a real circuit, all inductors have resistance.? In LTspice, the default internal resistance of L1 and L2 is 0 ohms because they are coupled, and the internal resistance of L3 is 0.001 ohm.? It's unlikely that your transformer has that little DC resistance in it.
?
Where else do you need help?
?
Andy
?
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Re: Passing a Mosfet Value as a parameter to a hierarchical subcircuit
Ooops. Still not having it. I shall sleep on things and try again tomorrow.
|
Re: Passing a Mosfet Value as a parameter to a hierarchical subcircuit
Apologies for setting things off and thanks for the additional replies. I upgraded to 24.1.8 and now it is working. I did have {MOS} set as the mosfet type for M1 and M2 in my subcircuit so it just ran after the upgrade with no complaints. I haven't checked it out fully but fingers crossed. Not sure about the 5 pin mosfet model for the Si7336ADP. It is listed in the 3 pin symbol mosfet picker.
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Re: Simulation of MMC 3-Level on Ltspice
Ich habe die ltspice-Datei unter dem Namen M2C single-phase SPWM112 auf Temp hochgeladen?
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Alright, Anyone else who can help?
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Help needed on simple examples to build an digital filter in LTspice with Vlad's filter models from the filters manual
Hi folks,
I am new in the forum and I think I have done already some real big magic in LTspice but now I struggle how I can add a chip internal digital filters after an ADC to my huge analog model of an automotive battery pack.
I am not interested in the involved 2MHz delta-sigma ADC function at all, there is an analog 100kHz AAF in front and the digital output is downsampled to 128us = ~8kHz, so this part is just working fine and flat in my frequency range, I just want to rebuild the two frequency lowpass filterings which are done digital inside an IC afterwards the ADC.
We are running them in matlab but I like to keep the huge analog model before that filters in LTSPICE.
I found Vlad's filter stuff but I am missing a simple example how to use it with my transfer function as I am beginner for digital filters and the complex examples on the filters manual seem to complex for my simple needs.
My needs are to rebuild two chip internal digital filters
?
1. digital PT1 Filter with 128us samples for LOWPASS 20Hz
K=2^(-N) ; N=6 -> K=1/64
?
Transferfunktion digital k / (1 ?- (1-k)*Z^(-1) ?)
?
AND
2. for a SINC FILTER with OSR=16 and 128us per sample
?
Transferfunktion digital 1/16 * (1-z^(-16)) / (1 - Z^(-1))
Can someone experienced add a model from the filter subs provided to my example simulation so that I can see how this is done and how it works and plot the output over frequency?
I started with an example I found via google from Helmut how to create the 128us delayed versions of my input sample (simple AC sinus)....it shows function on his OUT example but it does not execute my wanted transfer function on OUT2.
So either someone can fix my trial with the delayed voltages or show me how to use an already designed existing filter just with my simple coefficients?
I will uploaded .ASC and .PLT file zipped: "SINC Filter basic example needed.zip" to temp. (The provided filters.sub is not included, everyone should have it, same as for all the nice math.sub stuff I already use and love)
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Simulation of MMC 3-Level on Ltspice
As part of my studies, I have to simulate a single-phase modular multilevel converter MMC (3-level) on Ltspice. I have already connected the circuit with two voltage sources of 20V each, two submodules (one upper and one lower). In the simulation I work with sine PWM, for this I have also used two carrier signals. The output voltage should be a stepped voltage between +20V and -20V and after the LC filter should be a clean sinusoidal voltage. But somehow I am not getting the desired results. (clean signals). Can someone help me. Thank you.?
?
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Re: Calculate average value of a waveform under specific conditions using .meas command
On 06/05/2025 18:41, Andy I via
groups.io wrote:
On Tue, May 6, 2025 at 09:33 AM, Tony Casey wrote:
Assuming you want to calculate the average inductor
current:
.MEAS Imax max I(L_filter_dc)
.MEAS Imin min I(L_filter_dc)
.MEAS Imid param (Imax+Imin)/2
.MEAS Tstart when I(L_filter_dc)=Imid rise=2
.MEAS Tstop when I(L_filter_dc)=Imid rise=3
.MEAS Iavg avg I(L_filter_dc) from Tstart to Tstop
If I understand correctly, that would of course find the average
inductor current over one complete cycle.
?
But Ankit wants to find the average voltage over three
distinct time intervals, each of which is a portion of one
cycle:
- The rising inductor current,
- The falling inductor current,
- The interval where the inductor current is zero.
These three intervals are identified as t0-to-t1, t1-to-t2,
and t2-to-t3??-- or as d1Ts, d2Ts, and d3Ts -- in the second photo
that Ankit uploaded earlier today. ?
That is a little more challenging because one wants to
identify the starting and ending times of each of the three
semi-linear portion of the I(L) waveform, but there is some
noise (ringing) which makes finding the exact corners
challenging.
?
That is why I recommended adding guard bands.? Instead of
looking for
? ? I(L_filter_DC)=0,
Ankit may want to test for
? ? I(L_filter_DC)=50m
or some other number (75mV, 200mV, ?mV) that is not exactly
zero, but large enough to be unaffected by ringing.? Admittedly
it requires Ankit to accept the errors caused by measuring over
inexact time intervals.? I think it may be a necessary
trade-off.
?
The mechanics of putting that into one or a collection of
.MEAS commands is another matter.? Perhaps the syntax Ankit used
was incorrect (but we may never know because of unwillingness to
show the non-working .MEAS commands).? Or perhaps the tested
events never happened.? Unfortunately, the error message can be
the same in either case, making it challenging to diagnose.?
Breaking it up into multiple .MEAS commands does help and you
can see where it fails.
The screenshot caption simply states "Calculate average value of a
waveform under specific conditions using .meas command". So that's
what I did, assuming the interval was 1 cycle.
For finding a good estimate of the start and stop times of the
transitions, the best method is to look for the highest and lowest
values of the derivative of the repetitive waveform, and then find
the time when (say) 98% of those values are achieved, to allow for
inconsistent peaks (better with Tmax in the .TRAN directive) , e.g.
.MEAS MaxdV max d( I(L_filter_dc)) ; max +v derivative
.MEAS T1 when d( I(L_filter_dc))=0.98*MaxdV rise=1 ; start of 1st
+ve transition
.MEAS MindV min d( I(L_filter_dc)) ; max -ve derivative
.MEAS T2 when d( I(L_filter_dc))=0.98*MindV fall=1 ; start of 1st
-ve transition
.MEAS T3 when d( I(L_filter_dc))=0.98*MaxdV td=T2 rise=1 ; start 2nd
+ve transition
Then find the averages of whatever intervals are required.
--
Regards,
Tony
|
You have a huge inrush current due to the
capacitors being fed from a zero-impedance source V9. Put 1 ohm
in series with it. But the simulation still stalls without an
error message after less than 1 ms. As far as I can see, your
switching waveforms allow each pair of series FETs to be on
together, briefly, which is not good. But there is something
else that causes the simulation to stall, and I'm not an expert
on these circuits.
On 2025-05-06 18:51, arhamishtiaq42 via
groups.io wrote:
yes I've changed my inductance to 110us, 250us, 1us but
current is still high around 40A. and it is steady
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only
If something is true: * as far as we know - it's science *for
certain - it's mathematics *unquestionably - it's religion
|
I've updated my file with the name Dabnew.asc in TEMP folder kindly someone fix the current issue of my primary side transformer of DAB
|
yes I've changed my inductance to 110us, 250us, 1us but current is still high around 40A. and it is steady
|
You can't change L1 without also changing L2,
keeping their ratio constant. It would be OK to change L3 by the
same factor. So try L1=110? L2=250? and L3=1?.? It doesn't make
much sense to specify a very precise value for leakage
inductance unless you know exactly how the transformer will be
constructed.
On 2025-05-06 18:33, arhamishtiaq42 via
groups.io wrote:
On Tue, May 6, 2025 at 10:16 AM, John Woodgate wrote:
dabhw4_new
Thanks for replying. i put 11us so it made my output 150 if i
increase 11us to above it changes the output I've uploaded my
file in TEMP with the name of dabhw4_new can you tell what
should i do should i change mosfet ?
?
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only
If something is true: * as far as we know - it's science *for
certain - it's mathematics *unquestionably - it's religion
|
On Tue, May 6, 2025 at 10:16 AM, John Woodgate wrote:
dabhw4_new
Thanks for replying. i put 11us so it made my output 150 if i increase 11us to above it changes the output I've uploaded my file in TEMP with the name of dabhw4_new can you tell what should i do should i change mosfet ?
?
|
Re: Calculate average value of a waveform under specific conditions using .meas command
On Tue, May 6, 2025 at 10:44 PM, Andy I wrote:
It is not a problem to not want to upload a complete schematic and all the models - for whatever reason it may be.? But it would have helped if you could at least have shown us the .MEAS commands that failed.? It's a tantalizing way of saying, "It's broken, but it's a secret.? Now fix it."
Andy,
?
Understood. And that's a horrible mistake on my part. I am sorry about it.
Sorry.? I was reluctant to use pronouns, not knowing whether to say "his" or "hers" or maybe "theirs".? I hope I at least spelled it correctly.
Not offending anyone. Old times were good and simple, not many were offended about a him/her/their. People have simplified/diversified/complicated matters for their own good. Homo sapiens have really come far. I am a he though.
With Regards,
Ankit
|
John Woodgate
Tony Casey