Latest syntax checking improvement and related issues
I am not sure whether some of my libs got corrupted, but with the latest LTspice release and its stronger syntax check ie. the Bordodynov lib shoots huge number of errors which must be corrected otherwise the simulation does not start.
Usually errors are with TABLE syntax, but with typos as well (well, quite huge amount).
Any experience with that here?
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Re: Access .model parameters by name in expressions
Inside each .model there will definitely be default values stored somewhere, which could be returned if one is not provided explicitly in the .model statement, so I don't see why this couldn't be done. LTSpice is great for how it handles arbitrary expressions and behavioural devices, so I'm sure it would be possible to do such a thing if the developers wanted to.
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Thank you so much for taking the time to help me. I truly appreciate it.?
Can you please tell the purpose of ADuM3190-chip . this circuit is quite complex for me to understand as I am undergraduate student . how did you give pulse to mosfet surely from UC3875 gate driver but how you put PULSE command i can't understand how did you manage the switching frequency? at 30kHZ? can transformer work without this ADuM3190-chip?. .
Also i want to make the PCB of this circuit in KICAD software if you have any idea how can i design this transformer do i have to place the ADuM3190-chip in my pcb??
Thanks in Advance?
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1. The ADuM3190-chip was used to regulate the DAB-Converter. Open the datasheet to see what is inside the chip. This chip is operating much more linear, compared to other regulator configurations, such as
the combination of "voltage reference, together with an OP-Amp + Optocoupler". The optocoupler is known for it's nonlinearities and therefore more complicated to stabilize the converter.
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?? ?I just used the ADuM3190-chip to show an alternative solution. Its use is not mandatory, you don't need it.
????????
It is assumed you want to use the Transformer for isolation purposes, right?
In that case the regulation feedback loop needs to have an isolation as well.
Another alternative, for which an isolated regulation loop can be omitted, is the use of an isolated transformer-coupled Driver. In that case you will have the freedom to put the regulation circuitry to any ground point
- output Ground for instance - without the need for an isolated feedback loop. The isolated Driver provides a floating Ground. So, the regulator inside the UC3875 could be directly used for regulation.?
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2. The UC3875 gate driver outputs A,B and C,D can drive a transformer coupled driver or a Low side/-High side driver instead. For simplicity, I used voltage-dependent-voltage sources, which LTspice offers in its library as "e-sources". The switching frequency is accomplished by the R12,C8, connected to the FREQSET-Pin of the UC3875. For more information, pls refer to the datasheet, in which you find a curve for Rt=f(CT, frequency).
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3. The transformer(s) have nothing to do with the ADuM3190-chip at all.
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4. I can't assist you regarding KICAD. As mentioned above, ADuM3190-chip is not mandatory.
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5. For transformer design, pls refer to the following articles
? ? ? ?
and
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best regards
Udo
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Re: Access .model parameters by name in expressions
On 10/05/2025 10:10, andrewsimper via
groups.io wrote:
Thanks for the reply. I already know how to create a
parameter and use this value in a .model statement of transistor
/ diode etc, which is what you have shown, but unfortunately
this doesn't help with my question.
?
Is there a way to access a value defined in the .model
statement of a transistor etc, and then use that value elsewhere
in an expression?
?
Is there some syntax like: "getvalue(npnmodel, is)", or
"npnmodel.is", or something similar to grab the already defined
value out of a .model statement?
?
I scoured the LTSpice docos / online resources but and can't
find anything like this, so I am guessing the answer is no, but
I thought I'd ask here for an more official "no". I can
workaround it in other ways, but having this sort of access
would be really useful to prevent a bunch of manual text editing
every time I want to try out a different model and calculate
derived expressions from it.
I think your guess is correct. This isn't an "official "no". But
since the Gummel-Poon model, for example, is public domain, it would
in principle be possible to derive it from the actual
characteristics. There is another issue: in most models, some of the
parameters are not stated, so remain at their default value, which
is often zero, but not always. Therefore they couldn't be extracted
from the .model. I don't know for sure, but it's also possible that
not all simulators have the same default values. I would think this
is enough to deter you from this route, and probably why such a
reverse look-up doesn't exist.
--
Regards,
Tony
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Re: Access .model parameters by name in expressions
Hi Tony,
?
Thanks for the reply. I already know how to create a parameter and use this value in a .model statement of transistor / diode etc, which is what you have shown, but unfortunately this doesn't help with my question.
?
Is there a way to access a value defined in the .model statement of a transistor etc, and then use that value elsewhere in an expression?
?
Is there some syntax like: "getvalue(npnmodel, is)", or "npnmodel.is", or something similar to grab the already defined value out of a .model statement?
?
I scoured the LTSpice docos / online resources but and can't find anything like this, so I am guessing the answer is no, but I thought I'd ask here for an more official "no". I can workaround it in other ways, but having this sort of access would be really useful to prevent a bunch of manual text editing every time I want to try out a different model and calculate derived expressions from it.
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Re: Access .model parameters by name in expressions
On 10/05/2025 03:58, andrewsimper via
groups.io wrote:
I'm creating some subcircuits and would like to use some
parameters of a model in further expressions, but only have to
define the value once in the model itself. Is this possible in
LTSpice? For example can I use the saturation current of a
particular transistor model in a subsequent expression? eg:
?
* define a model with some parameters
.model npnmodel npn(is=1e-16 n=1.02)
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* access one of the parameters in an expression somehow to
calculate a derived value
* - the actual expression will be more complicated than just
*2
.param val = {npnmodel(is)*2}
If I understand you correctly - yes, this is possible. But rather
than try and describe it, I have uploaded one available solution -
undoubtedly, there are others.
Param-to-subckt-to-model
BTW, it is not necessary to use braces when assigning a numeric
value to a parameter.
--
Regards,
Tony
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Access .model parameters by name in expressions
I'm creating some subcircuits and would like to use some parameters of a model in further expressions, but only have to define the value once in the model itself. Is this possible in LTSpice? For example can I use the saturation current of a particular transistor model in a subsequent expression? eg:
?
* define a model with some parameters
.model npnmodel npn(is=1e-16 n=1.02)
?
* access one of the parameters in an expression somehow to calculate a derived value
* - the actual expression will be more complicated than just *2
.param val = {npnmodel(is)*2}
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Re: Single-phase H-bridge inverter circuit
In addition, I just uploaded my LTspice file here on our group.
I don't know how I can send it to you but It called invmono_analise_tent2. If you are available, maybe you can take a look on my circuit and share your opinion with me... Thanks again!
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Re: Single-phase H-bridge inverter circuit
Hi, Andy. Thanks for it! I have not known this way. So easier...
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By the way, I've noticed the noises I commented before should be my PWM configuration, I'm not able to configure my PWM considering the dead time, so at the moment when one turns off and the other turns on, there's a distortion in my PWM. Is there a standard delay value to consider?
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Re: Single-phase H-bridge inverter circuit
On Fri, May 9, 2025 at 07:23 PM, <guilhermesouzam01@...> wrote:
My load is purely resistive, so in theory, the waveform I should see across the resistor will be square-shaped with the same RMS voltage as the supply voltage (Vcc) of the circuit.
However, when I simulate my circuit, the waveforms appear distorted and noisy.
Are you sure you looked at the voltage across the load resistor?? The easiest way to do that in LTspice is:
- Position the cursor over one end of the resistor so that the probe turns red.
- Press and hold the left mouse button.
- Move the cursor to the other end of the resistor until the probe turns black.
- Release the mouse button.
?
Andy
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Single-phase H-bridge inverter circuit
Hello all!
I'm trying to design a circuit for my college project.
My load is purely resistive, so in theory, the waveform I should see across the resistor will be square-shaped with the same RMS voltage as the supply voltage (Vcc) of the circuit.
However, when I simulate my circuit, the waveforms appear distorted and noisy.
Could someone check if there's something wrong with my circuit or suggest any ideas?
I suspect that I'm also configuring my PWM sources incorrectly, maybe messing up the dead time... it's all a bit confusing.
You can find the schematic through the link below.
Thank you!
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[Link to off-site file on Google drive removed]
[Mod note:? Never point us to off-site storage.? Upload your schematic to this group's Files area.]
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Re: Simulation of MMC 3-Level on Ltspice
On Fri, May 9, 2025 at 05:43 PM, <Bouzid.wis@...> wrote:
Upper submodule: When the upper MOSFETs (e.g. S1) are conducting, the positive voltage of the upper capacitor is applied to the output, while the lower MOSFETs (e.g. S2) close the current path or bypass the upper branch.
I am sorry, but that description does not explain to me how it works, not in a way I can understand.? There are many things interacting here, including the fact that the source of pull-up current is through a resistor and an inductor, it is not a voltage source, and there is a capacitor in the current path when M1 switches ON.? Plus there is the reactive input impedance of the output filter.? M1 does not directly switch a positive voltage to the unfiltered output, which I think was what you think would happen.? For that to happen, R1 and L2 and C1 should not be there.
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Do you understand how it is really supposed to work?
?
the two submodules must be symmetrical to each other, can you show me where the problem is.
What is the problem?? Is there a problem?
?
Are the two submodules not symmetrical to each other?
?
I see a sine wave at the filtered output, and it looks like a reasonable replica of the input sine wave.? That suggests that maybe the circuit works.
?
yes I have looked at the file, but the output voltage should not look like this.
please have a look at the picture i uploaded in the temp named output.
I think you are mistaken if you think the unfiltered output should alternate between +20 V, 0 V, and -20 V.? I do not see a way for your first circuit to make the unfiltered voltage do that.
i also uploaded another simulation circuit (named M2C single phase SPWM11) where i simulated the circuit with only one carrier signal, but the unfiltered voltage is not stepped with clear voltage levels: +20V, 0V, -20V, but only +20V, -20V. Probably because I only used one carrier signal. But the current at the load and the filtered voltage look good.
How would the unfiltered output voltage go to 0 V?? Is there anything in your circuit that can drive the unfiltered output to 0 V?? I do not see one.
?
But I hope you realize I am unfamiliar with this circuit, and that does not help me explain what happens or does not happen.? I am "in the blind".
?
Andy
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Re: Simulation of MMC 3-Level on Ltspice
I have uploaded the picture in the photo under the album MMC single phase.
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Re: Simulation of MMC 3-Level on Ltspice
Thanks for your Answer.
?
How each submodule affects the output in a single-phase MMC
?
In a single-phase Modular Multilevel Converter (MMC), the output typically consists of an upper and a lower submodule. Each submodule can pull the output either up (positive voltage) or down (negative voltage) by switching the voltage of its internal capacitors.
?
Upper submodule: When the upper MOSFETs (e.g. S1) are conducting, the positive voltage of the upper capacitor is applied to the output, while the lower MOSFETs (e.g. S2) close the current path or bypass the upper branch.
?
Lower submodule: To pull the output down, the lower submodule (e.g. S3) switches its internal capacitor into the current path, while the lower bypass MOSFETs (e.g. S4) allow current to flow through the lower branch.
?
The change between these states is controlled by the PWM control signals, which use either V(tri_up) or V(tri_dwn) as the carrier signal to control the switching on and off of the MOSFETs.
?
the two submodules must be symmetrical to each other, can you show me where the problem is.
yes I have looked at the file, but the output voltage should not look like this.
please have a look at the picture i uploaded in the temp named output.
i also uploaded another simulation circuit (named M2C single phase SPWM11) where i simulated the circuit with only one carrier signal, but the unfiltered voltage is not stepped with clear voltage levels: +20V, 0V, -20V, but only +20V, -20V. Probably because I only used one carrier signal. But the current at the load and the filtered voltage look good.
?
|
Thank you so much for taking the time to help me. I truly appreciate it.?
Can you please tell the purpose of ADuM3190-chip . this circuit is quite complex for me to understand as I am undergraduate student . how did you give pulse to mosfet surely from UC3875 gate driver but how you put PULSE command i can't understand how did you manage the switching frequency? at 30kHZ? can transformer work without this ADuM3190-chip?. .
Also i want to make the PCB of this circuit in KICAD software if you have any idea how can i design this transformer do i have to place the ADuM3190-chip in my pcb??
Thanks in Advance?
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Locked
"A Conversation with Mike Engelhardt on QSPICE" in Power Electronics News
Power Electronics News just published this article:
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A Conversation with Mike Engelhardt on QSPICE
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Read it here:
?
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As you know, this group is not for QSPICE discussions.
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Andy
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Hi John,
pls refer to my "Add-on"-file ----- Udo
Thank you, but we really want .ZIP archives,
not 7z or any other sort.
On 2025-05-09 12:40, Udo
Huhn-Rohrbacher via wrote:
Hi All,
i have uploaded a zip-file named DAB500_zip.7z, placed in the
temp.-folder.
?
You will find the following files:
- Simulation file for the 500W DAB-Converter with same
specifications as previously discussed.
- one for static Load operation, to mdeasure the Efficiency,
which reached realistic 93% to 95%
- one for pulsed Load operation from 0,83A to 3,33A with
di/dt of 2,5Amps/usec.
- Also attached are lib-files, such as for the
UC3875-controller, the current transformer and a Compensator?
with isolated feedback loop. (Replacement for optocoupler).
?
Of course, the UC3875 phase shift controller is
old-fashioned, but enough to demonstrate the functionality of
the DAB-converter.
If anyone has a modern, up-to-date controller for LTspice,
kindly give me an input.?
?
With some minor modifications, the circuit may be used for
bidirectional power flow.
------
Udo
?
?
--
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
-- Dipl.Ing.Udo Huhn-Rohrbacher Albert-Kratz-Str.1 D-75180 Pforzheim phone: +497231-352339 fax: +497231-140338 mobile: +491523-3612096 E-mail: u.huhn.rohrbacher@...
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Thank you, but we really want .ZIP archives,
not 7z or any other sort.
On 2025-05-09 12:40, Udo
Huhn-Rohrbacher via groups.io wrote:
Hi All,
i have uploaded a zip-file named DAB500_zip.7z, placed in the
temp.-folder.
?
You will find the following files:
- Simulation file for the 500W DAB-Converter with same
specifications as previously discussed.
- one for static Load operation, to mdeasure the Efficiency,
which reached realistic 93% to 95%
- one for pulsed Load operation from 0,83A to 3,33A with
di/dt of 2,5Amps/usec.
- Also attached are lib-files, such as for the
UC3875-controller, the current transformer and a Compensator?
with isolated feedback loop. (Replacement for optocoupler).
?
Of course, the UC3875 phase shift controller is
old-fashioned, but enough to demonstrate the functionality of
the DAB-converter.
If anyone has a modern, up-to-date controller for LTspice,
kindly give me an input.?
?
With some minor modifications, the circuit may be used for
bidirectional power flow.
------
Udo
?
?
--
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
|
Hi All,
i have uploaded a zip-file named DAB500_zip.7z, placed in the temp.-folder.
?
You will find the following files:
- Simulation file for the 500W DAB-Converter with same specifications as previously discussed.
- one for static Load operation, to mdeasure the Efficiency, which reached realistic 93% to 95%
- one for pulsed Load operation from 0,83A to 3,33A with di/dt of 2,5Amps/usec.
- Also attached are lib-files, such as for the UC3875-controller, the current transformer and a Compensator?
with isolated feedback loop. (Replacement for optocoupler).
?
Of course, the UC3875 phase shift controller is old-fashioned, but enough to demonstrate the functionality of the DAB-converter.
If anyone has a modern, up-to-date controller for LTspice, kindly give me an input.?
?
With some minor modifications, the circuit may be used for bidirectional power flow.
------
Udo
?
?
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Re: Simulation of MMC 3-Level on Ltspice
Bouzid.wis,
?
See this schematic I uploaded:
in the Temp folder.
?
I swapped (interchanged) two of the signals.? Now it seems to work.? That confirms my suspicion that one of your sections was inverted or backwards.
?
Andy
?
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Tony Casey
John Woodgate