Re: Changing the mutual inductance coefficient of K statements with time
John Woodgate. Thank you very much for your comment. I have overwritten the file.
Bordodynov.
17.07.2013, 14:49, "John Woodgate" <jmw@...>:
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In message <181191374056872@...>, dated Wed, 17 Jul 2013,
=?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...>
writes:
Maybe you have to verify my idea of building a mutual inductances. The
coefficient K depends on the voltage. I put my example in the TEMP
folder. It doesn't run. There is confusion between Winding and Winding0
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
Thank you very much for your comment. I have overwritten the file
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Re: Changing the mutual inductance coefficient of K statements with time
In message <1374056490.61943.YahooMailNeo@...>, dated Wed, 17 Jul 2013, Dhara Weerasinghe <the_sky_falcon@...> writes: ?
Thanks so much for your help. I got it to work. I used :
?
K L1 L2 {X}
?
.step param {X} 0.01 0.07 0.01
?
Thanks again for your help.?
? It works in this case, but don't use X or x for an independent variable, because it has a special meaning in some contexts. {K} or {KA} work. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk Why is the stapler always empty just when you want it? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
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Re: Changing the mutual inductance coefficient of K statements with time
In message <181191374056872@...>, dated Wed, 17 Jul 2013, =?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...> writes: Maybe you have to verify my idea of building a mutual inductances. The coefficient K depends on the voltage. I put my example in the TEMP folder. It doesn't run. There is confusion between Winding and Winding0 -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk Why is the stapler always empty just when you want it? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
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looking for a model for AD8363
I have tried to search on the file content page without luck, Anyone can help me find this or any other RMS-DC converter.
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Re: Changing the mutual inductance coefficient of K statements with time
Hello Falcon.
Maybe you have to verify my idea of building a mutual inductances. The coefficient K depends on the voltage.
I put my example in the TEMP folder.
Bordodynov.
17.07.2013, 11:44, "the_sky_falcon" <the_sky_falcon@...>:
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Hello,
I am an electronics engineer and I work on wireless power supplies. For one of my simulations, I want to couple two inductors and I would like to simulate the design for various values of K.
Could someone please let me know why I can not use the following syntax as an LTSPICE directive?
K L1 L2 V(Var)
Where Var is a voltage source I have specified in the simulation circuit and it is a PWL (ramp function).
This syntax works for a variable resistor. I am wondering whether it is actually possible to apply the same logic to a coupling coefficient of the K statement.
Please help !!
Thank you.
Falcon
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Re: Changing the mutual inductance coefficient of K statements with time
Hi All,
?
Thanks so much for your help. I got it to work. I used :
?
K L1 L2 {X}
?
.step param {X} 0.01 0.07 0.01
?
Thanks again for your help.?
?
Falcon
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Re: Changing the mutual inductance coefficient of K statements with time
Falcon, what you surely can do is to uses parameter for K that you can change for each simulation (or even make several runs for this parameter:
K12 L1 L2 {k12}
.param k12=0.9
I hope that this helps.
Stefan
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El 17/07/2013, a las 09:25, the_sky_falcon <the_sky_falcon@...> escribi¨®: Hello,
I am an electronics engineer and I work on wireless power supplies. For one of my simulations, I want to couple two inductors and I would like to simulate the design for various values of K.
Could someone please let me know why I can not use the following syntax as an LTSPICE directive?
K L1 L2 V(Var)
Where Var is a voltage source I have specified in the simulation circuit and it is a PWL (ramp function).
This syntax works for a variable resistor. I am wondering whether it is actually possible to apply the same logic to a coupling coefficient of the K statement.
Please help !!
Thank you.
Falcon
|
Re: Changing the mutual inductance coefficient of K statements with time
--- In LTspice@..., "the_sky_falcon" <the_sky_falcon@...> wrote:
Hello,
I am an electronics engineer and I work on wireless power supplies. For one of my simulations, I want to couple two inductors and I would like to simulate the design for various values of K.
Could someone please let me know why I can not use the following syntax as an LTSPICE directive?
K L1 L2 V(Var)
Where Var is a voltage source I have specified in the simulation circuit and it is a PWL (ramp function).
This syntax works for a variable resistor. I am wondering whether it is actually possible to apply the same logic to a coupling coefficient of the K statement.
Please help !!
Thank you.
Falcon
Falcon, The correct syntax for assigning a variable to the coupling factor is: K1 L1 L2 {Var} .step param Var StartVal StopVal Inc ; substitute your own values ... same as it is for any other component value. Regards, Tony
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Re: Changing the mutual inductance coefficient of K statements with time
Hi Jerry,
?
Thanks for the reply. The problem is, with wireless power supplies, the coupling between the primary and the secondary windings are very week. Therefore I can not get a figure for the leakage inductance.?( Ie: in a flyback transformer, I can short circuit the secondary and measure the primary inductance at 100kHz and use that figure for simulation with another uncoupled inductor put in series with my flyback primary inductor). However this method wont work for wireless power supplies as the coupling is very week. (If I short circuit my reciever coil and measure the inductance of the power transmitter track, the difference of inductance is miniscule.
?
Is there any other way of doing this? I can of course simulate for various values of k but I am very curious.
?
cheers,
?
Falcon
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Re: Changing the mutual inductance coefficient of K statements with time
I have a feeling you should explicit the leakage inductances (i.e. making them visible components in the schemo) and apply the statement to them. Le 17/07/2013 09:25, the_sky_falcon a ¨¦crit :
Hello,
I am an electronics engineer and I work on wireless power supplies.
For one of my simulations, I want to couple two inductors and I would
like to simulate the design for various values of K.
Could someone please let me know why I can not use the following
syntax as an LTSPICE directive?
K L1 L2 V(Var)
Where Var is a voltage source I have specified in the simulation
circuit and it is a PWL (ramp function).
This syntax works for a variable resistor. I am wondering whether it
is actually possible to apply the same logic to a coupling coefficient
of the K statement.
Please help !!
Thank you.
Falcon
[Non-text portions of this message have been removed]
|
Changing the mutual inductance coefficient of K statements with time
Hello,
I am an electronics engineer and I work on wireless power supplies. For one of my simulations, I want to couple two inductors and I would like to simulate the design for various values of K.
Could someone please let me know why I can not use the following syntax as an LTSPICE directive?
K L1 L2 V(Var)
Where Var is a voltage source I have specified in the simulation circuit and it is a PWL (ramp function).
This syntax works for a variable resistor. I am wondering whether it is actually possible to apply the same logic to a coupling coefficient of the K statement.
Please help !!
Thank you.
Falcon
|
Re: inductance with a permeability in dependency of frequency
--- In LTspice@..., legg@... wrote:
Here's an example of a material exhibiting reduced permeability with frequency.
RL
RL, The link doesn't show anything about permeability vs. frequency. Rick
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LTspice does not link to external programs or code. But it has a capable user-programmable component in the form of the BI behavioral element. It is a current-output device. If you can write an expression for what you want the current to be, using the rules listed in the Help file, you can create a BI element that does it. Take a look in the Help utility under LTspice > Circuit Elements > B. Arbitrary Behavioral Voltage or Current Sources. The Help for Dot Commands .FUNC and Dot Commands > .PARAM may also be useful. Regards, Andy
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this is my component matlab codes. my ?nput is voltage and my output is current (I). I think my component has one input and one output. I want to create new block and my block must work as below. when i apply sine wave to input i must take current from my output. is there any code part in ltspice (using any language)
"Ron=1000;
Roff=160000;
x(1) = 0.5;
xDiff = 0;
time_step=0.0001;
t = (0:time_step:1);
voltage=sin(2*pi*t);
I = zeros(size(voltage));
for i=2:length(voltage),
? ? ? ? ?
? ?M(i-1)=(Ron.*x(i-1))+(Roff.*(1-x(i-1)));
? ? F=(1-((2.*x(i-1))-1)^20);
? ??
? ? ?I(i-1)=voltage(i-1)/M(i-1);
? ? ?dxdt=66000*I(i-1)*F;
? ? ?xDiff = dxdt*time_step;?
? ? ?x(i)=x(i-1)+xDiff;
end
?plot(voltage,I);"
________________________________
From: Yunus Babacan <baba_yunus_24@...>
To: "LTspice@..." <LTspice@...>
Sent: Wednesday, July 17, 2013 2:41 AM
Subject: [LTspice] New component
?
hi, I want to make spesific electronic component.. my component contents codes.(for which etc... in matlab). can i make my component using codes. is there any property of ltspice..if answer is yes, how can i make ??
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Re: differences between LTSpice models and IR models
Excellent, thanks Rick !
I have a lot of the intusoft documentation but there is
so much good stuff it is sometimes hard to weed out
what I need. Eq. 1.7 sure enough looks like the one
I needed !
boB
TT can be computed from the diode storage time, TS, using the
following equation:
Eq. 1.7
where IF is the forward current and IR is the reverse current.
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--- In LTspice@..., "sawreyrw" <sawreyrw@...> wrote:
--- In LTspice@..., "boB G" <bob@> wrote:
OK, it was kind of unclear and I don't think that message thread ended up saying this, exactly.
I would have thought that Trr would be reverse recovery time.
Transit Time seemed like it was for something else.
So, what is the difference between Trr and TT ? Is there any ?
Can a VDMOS model have Trr specified as well as TT ? Are they
interpreted the same ?
I would love to see some documentation on that. At least I would
like to see this listed in the LTspice help file.
Thanks,
boB
boB,
One of the best documents I have seen on modeling devices is WkwModels.pdf. Google for it. Eq 1.7 gives you the relationship between the storge time (Ts, not Trr) and Tt. Tt is also used for the VDMOS diode.
Rick
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Re: differences between LTSpice models and IR models
--- In LTspice@..., "boB G" <bob@...> wrote:
OK, it was kind of unclear and I don't think that message thread ended up saying this, exactly.
I would have thought that Trr would be reverse recovery time.
Transit Time seemed like it was for something else.
So, what is the difference between Trr and TT ? Is there any ?
Can a VDMOS model have Trr specified as well as TT ? Are they
interpreted the same ?
I would love to see some documentation on that. At least I would
like to see this listed in the LTspice help file.
Thanks,
boB
boB, One of the best documents I have seen on modeling devices is WkwModels.pdf. Google for it. Eq 1.7 gives you the relationship between the storge time (Ts, not Trr) and Tt. Tt is also used for the VDMOS diode. Rick
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Re: 3722 Power Supply Problem
Well that explains most of the shoot-through. You don't see any when the nodes are reconnected?
The compensation values are overkill. Feel free to fiddle with or remove any of them. Just watch what the IC comp pin does during start-up and line/load variations, though, as you make your changes.
As has been suggested elsewhere, the large inductance values of your transformer are prime limitations to power transfer, when current is expected to reverse each cycle. The leakage inductance induces extra dead-time in the output rectifier, robbing you of headroom.
Also, with the turns ratio used, at 18V, you're close to drop-out anyways. If you expect to induce double output current peaks in the output inductor, you'll need extra headroom.
It is strange conjunction of power train component values. How did you select them? You'd normally think of magnetizing current as a fraction of that being transferred, unless it was aggravated intentionally to perform some other function.
RL
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--- In LTspice@..., "viperlenny" <viperlenny@...> wrote:
RL,
Thank you for taking a look but I still have an issue. The bridge nodes that you renamed now disconnected the ZVS circuit of the chip because the nodes have been renamed to SWAB and SWCD the SWT and SWB nodes are no longer connected and are left floating.
Also when the when the input power supply drops to 18V the regulation of the 165V rail is not kept.
I would also appreciate it if you could tell me how you came to derive all of the compensation values.
Thanks for your help.
Leo
--- In LTspice@..., legg@ wrote:
--- In LTspice@..., "viperlenny" <viperlenny@> wrote:
Hello,
I am trying to make a power supply using a 3722-1.
The input is 18 to 30Vdc and output is 165V@
The issue that I am having is that at low input voltages like 24V or 18V the power supply is not able to reach full output level. At 30V the output level is reached but regulation is poor.
There's nothing wrong with the model, as such, but there seems to be a couple of issues with the circuit that you're simulating.
If you overcompensate it, you'll get a better idea about what is going on in the power train, as the control circuit will not be responsible for cycle by cycle variations.
There should be an overcompensated example posted in the temp files shortly.
In the working model, there is a shoot-through current occurring quite regularly. I don't know whether this is the result of intentional values placed in the drive delay circuits.
In real life, such spikes would invoke irregular limiting behavior in the 3722 that you'll want to avoid.
As to power throughput with reducing input voltage, you should take a look at the current waveforms and decide for yourself where the limitation lays.
RL
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Re: inductance with a permeability in dependency of frequency
--- In LTspice@..., John Woodgate <jmw@...> wrote:
In message <krbus2+ba2e@...>, dated Sun, 7 Jul 2013, Herbert
<afu@...> writes:
dows anybody have an idea for modelling a inductance with a
permeability in dependency of frequency ?? I want to go right back to the beginning. Because you gave very little
information, people have assumed various things and that can make the
whole thing complex and confusing.
First of all, what frequency range are we in, and what is the material
whose permeability depends on frequency? Secondly, is this material
significantly lossy in that frequency range or not?
For example, if you are looking at nickel-iron at audio frequencies, the
losses are secondary, but if you are looking at ferrites at radio
frequencies, then whether the losses are significant or not depends on
which grade of ferrite you are looking at.
If the losses are NOT significant, then why bother with permeability?
The inductance is proportional to it, so you can just use a table of
inductance against frequency.
If the losses ARE significant, you CAN model as L and R parallel but
both need a table of values against frequency.
Here's an example of a material exhibiting reduced permeability with frequency. RL
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hi, I want to make spesific electronic component.. my component contents codes.(for which etc... in matlab). can i make my component using codes. is there any property of ltspice..if answer is yes, how can i make ??
[Non-text portions of this message have been removed]
|
Re: differences between LTSpice models and IR models
OK, it was kind of unclear and I don't think that message thread ended up saying this, exactly.
I would have thought that Trr would be reverse recovery time.
Transit Time seemed like it was for something else.
So, what is the difference between Trr and TT ? Is there any ?
Can a VDMOS model have Trr specified as well as TT ? Are they
interpreted the same ?
I would love to see some documentation on that. At least I would
like to see this listed in the LTspice help file.
Thanks,
boB
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--- In LTspice@..., "sawreyrw" <sawreyrw@...> wrote:
--- In LTspice@..., "boB G" <bob@> wrote:
Sorry to beat a dead horse (I like horses), but did anybody ever figure out if LTspice can actually simulate reverse diode recovery
properly or not ???
I see Helmut's postings too, (msg_43634), but still
can't quite figure out if he is adding a separate diode
in his model or how it connects to the D-S of the FET model if it does.
BTW, searching the help for "recovery" doesn't seem to come up
with anything relevant.
Thanks,
boB
boB,
The standard SPICE diode model uses Tt to model reverse recovery, and thereby, stored charge. The diode capacitance will also have some effect on the dynamic reverse current. This model is reasonably accurate for abrupt recovery diodes, but may not be useful for a soft recovery diode.
Rick
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boB G