LTspice tutorial - Modeling transformers
ฝัง
- เผยแพร่เมื่อ 2 ต.ค. 2024
- #102 #ltspice
In this video I look at how a basic transformer can be modeled in LTspice and what are the common simulation particularities to watch out for. Afterwards, I perform some measurements on a practical transformer and try to implement that. Finally I look at some datasheets to see just what sort of parameters are commonly available.
References and further reading:
The LTSPICE IV simulator; Brocard; Wurth Elektronik; Cap 17.8 to 17.28
Analyzed datasheets:
www.haloelectro...
www.coilcraft....
LTspice Tutorial series:
EP1-Getting started:
• LTSpice Tutorial - EP1...
EP2-AC simulation and the Baxandall tone control circuit:
• LTspice tutorial - EP2...
EP3-.param and .step directives:
• LTspice tutorial - EP3...
EP4-How to import libraries and component models: • LTspice tutorial - EP4...
Ep5- Stock example simulations to play with: • LTspice tutorial - Ep5...
Ep6- Basics of FFT analysis and .four statment: • LTspice tutorial - Ep6...
EP7- Dependent voltage and current sources
• LTspice tutorial - Ep7...
Ep8- Turning a datasheet into a component model
• LTspice tutorial - Ep8...
EP9- Independent voltage and current sources
• LTspice tutorial - Ep9...
Ep10- .wave statement and audio file processing
• LTspice tutorial - Ep1...
Ep11 The effect of temperature on your circuit
• LTspice tutorial - The...
EP12 Modeling a DC brushed motor
• LTSpice Tutorial - Mod...
Ep13- Worst Case, Monte Carlo and Gaussian statistics circuit analysis
• LTspice tutorial - Wor...
EP14 - Digital circuits and logic gates • LTspice tutorial - Dig...
EP15- SMPS EMI and electrical noise and filters
• LTspice tutorial - SMP...
EP16- Feedback loop simulation
• LTspice tutorial - Fee...
Ep17 - Verifying Simulation Models
• LTspice tutorial - Sim...
Ep18 - Simulating Capacitors
• LTspice tutorial - Sim...
Ep 19 - Simulating Inductors
• LTspice tutorial - Sim...
EP 20 - Noise simulations
• LTspice tutorial - Noi...
Ep21 - Models and Libraries
• LTspice Tutorial - Cre...
Ep22- Voltage and current limited source
• LTspice Tutorial - Vol...
Ep23- Measuring Power Factor
• LTspice tutorial - Mea...
Ep24 - Modeling a vacuum tube triode
• LTspice tutorial - Mod...
Ep25- Using standard symbols
• LTspice tutorial - Re-...
Ep26- Modeling transformers
• LTspice tutorial - Mod...
Special Thanks to all my supporters on Patreon! Especially @afiskon and Ralf B.!
If you liked this video be sure to check out my other videos and you can also subscribe to be up to date with all the new ones!
If you want to support the creation of more and better videos please consider checking out: / feszelectronics
Wow, the finest inductor transformer video on youtube. Thanks for sharing your expertise and time.
This is very thorough guidance. I liked the attention to detail.
Great video!
One important thing I would like to mention is that these are small signal parameters.
Especially under load the primary inductance will be less. This is even more significant with a DC current through it. Eventually it will totally collapse when being driven into saturation.
absolutely unprecedented video! thank you very much. these simulation modelling of the non ideal parameters of components are so valuable. I hope and I wish you will also prepare a video about a converter EMI and LISN simulation on LTspice. that would be a greater unprecedented video!
I'm happy you enjoyed the video! I do plan on looking into more detail on conducted emission testing and LISN's this year.
Great video!
I noticed an issue though, at 11:20 or so. C4 is shorted to ground on each end! The bottom side of L3 and left side of C4 are connected to ground (Node 0) and the bottom side of L5 and right side of C4 are also connected to ground (Node 0 as well). One bottom side or the other needs to be isolated from the ground by at least a large resistor, or by using enough Rser in the L3 and V2 so you don't get a problem in the sim. My point being, to get an accurate simulation out of the bottom circuit you need to put all 18pf on C3. The same issue exists on the top schematic, too.
Great part on the stray capacitance and inductances and how to calculate the coupling factor!! I've never actually seen that set down before.
Thank you for an excellent video on simple high frequency transformers.
A followup video could be on simulation of different magnetic materials.
Yes indeed. Metglas...
Timestamps / Chapters
0:00 Intro
0:41 What is a Transformer?
2:05 Simulating Coupling
4:12 Multiple Coupling Factors
5:30 Pro Tip: Don't have floating circuits
6:26 Characterising a Transformer for LTSpice
7:07 Measuring Coupling Factor
8:10 Measuring Coupling Factor for the Tesla Coil
8:57 Measuring Interwinding Capacitance
9:44 Building a Characterised Model
10:27 Another Model Type
11:00 Comparing Models
11:33 Simulation Results
11:49 Characterising via a Datasheet
13:50 Outro
This is a really good tutorial on finer details of modeling a transformer. From my understanding, all of the voltage related modeling is there, however from power and efficiency standpoint, I couldn't find the core loss component. Is it somehow already covered in this model?
Great video, I was hoping you would cover this area in LtSpice. The sparkstarter channel did a video some years ago on simulating and tuning a Tesla coil, but he did not go into the details of how he created his Spice model. Would be great if you could do a video on this subject. Again many thanks for all your content.
Very interesting about LTspice modeling you may also simulate the magnetic hysteresis as well with LTspice. However measuring high inductance such as 200 H ou 700 H are very difficult
Fantastic! Thank you for these high-quality materials. I really enjoy watching your videos.
One important thing that I believe can make your videos more powerful and unique is that you mention what is the reference of the information you are providing (No other TH-camr does this), be it a book, an application note, etc.
Well, if its an online source, I always try to provide it, but if its a book, then its a bit more difficult; I mean, its not hard to provide book name, chapter, page etc. but its more difficult for the viewers to find it - if they don't have the book then its not a useful reference. What do you think?
@@FesZElectronics Actually, with nowadays online libraries, online book stores, massive libraries of universities, etc., I think finding a book is not that much a big deal. In the worst-case scenario, one can find a similar book based on the title you are providing. So I would prefer to know the book. Thanks again for all of your efforts :)
I will keep this in mind, and try to add references in all future videos. Thank you for this suggestion!
@@FesZElectronics That's great, Thanks!
Hi Fesz, thank you for the detailed video. In the last part of the video, datasheet have the values of insertion loss and reflection loss.
Can you also explain how to validate our model with these values?
Fantastic video.
One question that I had; how would I go about converting my transformer model that I created in a schematic into a SPICE model? This is so that I can have it in my library to be used in other schematics or to export to other SPICE simulation software (ie: NI Multisim, TINA, etc).
Great Video! I didn't know about the simple formula to measure the coupling factor, thanks for that!
Thanks
Yes, I do find it surprising that LTSpice does not include a model for a transformer as contrary to what we might think, these components are far from non-existent even in present-day electronics.
Hopefully, we can now remedy this deficiency courtesy of this info.
Good for higher studying student. :)
Awesome channel! Fills a great void in youtube teaching electronics videos.
👋 hi how can we simulate rf balun transformers with ferrite core???
good information, thank you, sir.
nice
But what about coupling capacitors if both windings are grounded? What they must be?
LTspice circuit at time 9:46 seems to indicate that C2 is electrically shorted. If so, it may be necessary to change the value of C1 on that circuit to 18pF.
Hello Frank! I did short C2 but I would not re-distribute the capacity; I was showing a recommended way of creating a model; the interwinding capacity is not perfectly distributed, but even so, by shorting a line between primary and secondary will reduce the effect of this capacity - it should not be connected in a way to have the highest value, but in a way to be uniformly distributed.
Also the impact of the inter-winding capacity is most visible when there is no short between primary and secondary, with such a short circuit any effect is minimized.
Great as always! Thank!!! Can you ever show how to (with LTspice) measure output (input) impedance of PA?
Great suggestion! I will try to look into this at some point soon!
Can you try short circuit calculation and doing examples how the welder transformer can stand to short circuit also you can give example of deferent way to increase the impedance to protect the transformer and also to decrease the short circuit currant like leakage inductance thank you
@@FesZElectronics I had in mind power amplifier, for example, with npn, .... I am sorry for my english, thanks for your videos !!!
Please make video how model in LTSpice real pulse transformer, I.e with exact saturation with the air gap I have. I’m interested in simulating exact unknown transformers I have.
Thank you
Love this channel. Keep you the great work. Also, any idea if possible to make a video about designing/selecting input EMI and AC Line power filters to meet Conducted Emissions and Surge Immunity (EN/IEC 61000-4-5)?
thanks
Nice.
Is the Lopen and Lshort at the video 7:57 the same as Lopen and Lleak in your video at 12:20?
Can you please make a video on Current Transformer (CT) simulation..
I really enjoy watching your videos.thanks
Thanks! It's what I was looking for. Now let me try to apply what I have learned to a real situation.
Thanks’ for this fine and simple explanation. Right to the point!
My problem is that I was unable to find the information requested to build your model. Is it possible to have a guess? For a 500W, 230V transformer delivering 34+34V at this output? The only thing I was able to find that the regulation should be 5%. Thanks again.
Hello Teodoro! Well, based on the data you provided, the only thing that could be extracted is the turns ratio (not how many there are, but the ratio on primary to secondary); I'm not sure what the 5% regulation refers to - it could have something to do with the inductors ESR, how much the voltage drops based on the current flowing trough the inductors. If you have a particular transformer in mind, you could extract more data from a datasheet. If not, just as an example, you could search for a random 500W trafo on any major electronics website and see what data you can find like that in the provided datasheet.
Hi Fesz, thanks for the great video. Can you elaborate a bit on the test frequency used when measuring your transformer? I have a 400 Hz transformer but want to evaluate the transformer under a 1Mhz lightning fault condition I need to meet. The inductances change when I set the LCR up for 400Hz vs 1 MHz test frequency. Is there an error is my measurement method or should I measure the parameters and build a new model for every frequency scenario I wish to consider
Its perfectly normal for the transformer to change its behavior based on frequency. The main reason for this is the magnetic permeability of the core is frequency dependent. You will find that as frequency increases, permeability drops, but also the transformer becomes more lossy - less of the magnetic energy is transferred to the secondary and more is converted to heat. I think it would be best to treat the transformer differently for the 2 cases - 400Hz vs 1MHz, so have different models, not just on the inductance side, but also the coupling and losses side, to get the best accuracy.
happy new year, friend!
Un pic cam devreme, dar An Nou Fericit!
This is a great video, thank you
Nice explanation.
Mr. FesZ, can you give the source for leakage and coupling inductance formulas?
Sure - one common source is en.wikipedia.org/wiki/Leakage_inductance and en.wikipedia.org/wiki/Inductance#Coupling_coefficient
Thanks fot this video. I have learned a lot on inductance but on LTSPICE modeling too ! Tanks again
Thank you! I'm happy you enjoyed it!
Very-very good!
A good powerful breakfast.
Enjoy your meal :D
Sir, Which is better software for Simulation between MATLAB and LTSpice?
Well, Matlab is specifically made for mathematics, LTspice is for circuit simulation