I see 13.56 MHz & think industrial RF heating.

--

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I think you need to upload the data sheet as a PDF to Files >Temp, and then tell us you did that. We need to read it in detail to see what those specifications are about. Does the manufacturer expect that the power supply will be connected to a remote load by coaxial cable?

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I suggest you direct your question the manufacturer Gambetti.

Try to understand what 'reflected power' means in a 13.56 MHz RF power supply. The wavelength for 13.56 MHz is more than 20 m. Therefore, I think a 13.56 MHz power generator still falls into the lumped element circuit domain. However,? definitions like 'reflected power' and 'VSWR' appear in the power generator's datasheet. I get confused about the physical meanings of 'reflected power'. What does it mean when it shows 'reflected power' 100W? Can someone kindly explain it?

Thanks a lot,
Min

Hello Andy & Tony,

Thanks for your help. Yes 200 ohm was not able to trigger ACST (mV output), increasing that to 1K in high side switching mode made circuit working though simulation time is quite long. This is auto switching in Q-1 & Q-3.?

Regards,
jagdish

Fred,

Because the file you uploaded mentions "inrush current"? --

Note that the inrush current (and the time to charge the capacitor) depend on what diodes you use for D1-D4.? With the default diode "D", the peak inrush current was almost 13 Amps.? But it might be only 6 Amps or less depending on the diode you pick (and in that case, it takes twice as long?for the capacitor to charge).

Andy

Remember to discuss QSPICE in the QSPICE group, not the LTspice group.

Andy

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Hi Mike

Thank you and your buds for making this happen
Looking forward to trying it

Is it wineable?
If not, then when possibly?

Today is the day.? My new simulator, formerly called S·P·Q·R, released today as QSPICE.

-- 
AC2CL
I do not think there is any thrill that
can go through the human heart like that felt by the inventor as
he sees some creation of the brain unfolding to success...
Such emotions make a man forget food, sleep, friends, love, everything.
- Nikola Tesla

Hi.
Ltspice comes with :
-linear inductors (no saturation)
-Non linear inductors (arbitrary magnetic flux definition in the form Flux=function() ) Input Flux= in the inductance line? of the inductor. But that does not help much for accurate modelling.
-Chan model Non linear inductors (these expect Br Bs Hc parameters, Br is B flux remanence, Bs is B field saturation, and Hc is H field coercivity) These can be read from a BH curve. (relationship between magnetic field H (Amperes/m) and magnetic flux B (Tesla))

The problem is that core manufacturers do not usually publish BH curves in their datasheets nor Br Bs and Hc parameters.?
But BH curves can if, I remind well, be obtained with some PSPice tool.



Other way is to obtain a BH curve with a BH curve meter plug into an oscilloscope. If you have a core sample. There are some circuits available on how to build one or they can be bought.

Finally the Chan model needs the core geometry. (core section area and magnetic length). These can be calculated using basic toroid geometry formulas.

Ltwiki has an article about The Chan model.


This resource is also helpful :



There is also an even more accurate model : the Jiles Atherton model (very slow) named CoreJA by Mr Bordodynov. (although I did not use it personnally)
Finding Jiles Atherton parameters can be even harder. Thankfully There is a magnetic.txt file attached to the CoreJA Model with some cores parameters.

Hope you find this information helpful

Hello Tony,

Thanks for pointing these errors.?
yes, I read the advisory of 20us in top of model file.
I will try yours & Andy's updated library again & let you know the results.?

jagdish

Yes, correct gate is auto biased for full AC signal (no phase control) & just switching mains voltage to load ON/ OFF which is main function of ACST rather than phase control.

jagdish

Yes, ACST device is bit different from Triac. It is specific AC switch just used to ON/OFF mains supplies to load.? Some more information about that,


The connections are made considering the pins as per details of ACST model & datasheet.

OK, I shall be removing E from resistor values in future.

jagdish

Hello Andy,

I will take care of no uploading RAW or LOG or . NET files. Also I am aware of fixing time step too small errors, thanks for providing the document again. However, my basic idea here was to get rid of the curly braces error.

jagdish

Fred,

By moving the ground connection from below C1 to below V1, you also need to change your .IC statement, so that the initial voltage is applied across the capacitor:

? ??.ic V(C1node,N002)=0

You don't want to start the simulation with V(C1node)=0 when the other end of C1 is not grounded.? The results are rather bad if left that way.? That's why you got the unexpected results.

Two other suggestions:

It's a Really Good Idea to name the net connected to the bottom of C1, after moving the ground from there to below V1.? By leaving the net unnamed, it inherits the temporary nodename N002, which can change on you if you make other changes to the schematic.

The other thing I recommend is not using the default diode "D".? D is an idealized diode model with zero resistance and capacitance, which are known to sometimes cause simulation problems.? Sometimes it's OK, sometimes not.? Any of the diodes from the "Pick New Diode" menu have realistic values.? The D diode model is the standard one from SPICE, 50 years ago.? As it happens, with the right .IC statement, any diode is good enough; but with the wrong .IC statement AND the "D" diode model, LTspice struggles.

Andy

Hmmm. Like I said, I have a lot to learn about the software. I uploaded capacitor_charging.asc to the files section. What I have in that schematic works. I can create a current probe in the resistor and just put one voltage probe at the top of the capacitor. If I move the ground to the left side where I left a wire stub under the voltage source and use a differential probe from the top to the bottom of the capacitor, I get the unexpected results.

Fred

Fred wrote, "I figured you could only have one ground, but put it on the input side based on examples from the web"

Yes, if you have more than one ground, just be aware that they get connected together, which might or might not be what you want.

It is pretty much arbitrary what point you choose to be your "ground", as long as you remember that any voltage you probe should be a voltage BETWEEN two points.

? ? "If anyone else sees tutorial like I saw with the ground before the bridge and using the differential probe by holding down the left mouse button for the red probe, then moving the resulting black probe to the output ground, it doesn't work, at least not with a signal over a few hundred Herz."

I can tell you that what you described definitely DOES work.? It's what we frequently remind people to do.? If it didn't work, then I guess something went wrong when you tried it.? There is no reason why it would not work or that it would be bandwidth limited.? It's not.

Some SPICE models can have hidden connections to global ground.? Then, changing the point that gets connected to ground would make a difference when they are part of the simulation.

Andy

Thank you for correcting my mistake in posting. I was coming back to say I found the issue and have a tad more to learn about LTSpice. I figured you could only have one ground, but put it on the input side based on examples from the web (Aren't all youtube videos vetted? ;) ). When I moved the ground to the output side, I got what I expected. If anyone else sees tutorial like I saw with the ground before the bridge and using the differential probe by holding down the left mouse button for the red probe, then moving the resulting black probe to the output ground, it doesn't work, at least not with a signal over a few hundred Herz.

Fred

Someone named "FlightRisk" attempted to send a message to the [LTspice] group an hour ago, wondering why there are "wild voltages and currents" with her/his rectifier circuit.? But they probably did not read the group's main webpage, and ignored the advice to NEVER USE ATTACHMENTS in messages.? So their message was rejected.

FlightRisk, if you have a schematic to show us, please upload it to the "Temp" folder in the group's?Files section.? Then tell us that you did it.? If you have pictures, we are not interested, so please don't upload them.? All we need is your schematic.? It's a *.ASC file.? By running the simulation, we can see the same thing you saw, making pictures unnecessary.? But if you absolutely need to show pictures, they should be uploaded to the group's Photos section.? However, the schematic (ASC file) is worth 1000 pictures.

I'm guessing here, but there is a fair chance that you did not pay attention to your grounds.? The bridge rectifier should not be grounded on both sides of the rectifier, so you need to pay attention when plotting those voltages.? Plotting ground-referenced voltages on the side that doesn't have a ground, just messes up the plots.? If you did ground both sides of the rectifier, the short circuit you added probably messes it up.? Alternatively, if your source includes a transformer, the transformer's SPICE model might be ringing in response to the square waves.? Also transformers can be tricky to simulate because the source "turns on" instead of running continuously.? Best to see your schematic (*.asc file).

We might not hear back from FlightRisk for a while, not because of their name but because they set their email delivery to the daily summary.

Andy