One year ago I made a video about LLC, but it wasn't soft switching and the waveform were wrong. This video is the correct version, sorry for that! Hope you enjoyed
Hi Mano, I have bumped into your channel and I have been viewing in order full of your videos. I would like to say a special thank you for your great efforts. My questions is that what are the differences between Lm1 and L1 in the transformer? Lm1 is participating resonant tank equations, and L1 is considered as transformer operation? In real LLC transformer, how can we extract/measure Lm1 and L1 by using LCR meter to distinguish their values? Thanks in advance!
Hi! Thanks for your comment So in order To create a transformer in LTSPICE, you need two coupled inductors, hence L1 and L2. You need also the parameter K L1 L2 1 to ensure that L1 and L2 are magnetically coupled. If K is less than 1, you are modelling also non ideal coupling. L1 and L2 are related to n^2, hence, if L1=400m and L2=1m, it means that the turn ratio of the transformer is 22 Input 1000V, Output 1000/22 Now Lm1 and Lr1, Lr2 Lm is the magnetizing inductance. In the LLC tank resonator, it has a pivotal role since it performes ZVS on the primary by changing energy with the Cds parasitic capacitance of the SiC mosfet of the primary Full Bridge. To do that, you need precise dead time. Hence Lm and Cr will be responsible for the ZVS on the primary. That's the first frequency. Lr is the leakeage inductance. His role is mainly to give the series resonant frequency for the ZCS (not ZVS, take care) of the secondary synchronous bridge. The current will be modulated by this series LC to make the current go to zero naturally before the mosfet starts commutating. Now, how to measure them You use instruments like Bode 100 and study the primary impedeance, and with some heavy formulas, extract the parameter. Trust me on this, it's a job I am doing, as a Power Electronic Hardware Designer. Fun for the first 10 minutes, heavy after a month. Feel free to ask
@@manoA98A Thank you for your quick response. I really really appreciate it. It sound silly but I am still having a little confusion here for Lm1 and L1. I could measure Lm1 when the secondary is open-circuited by Bode100 or LCR meter. I could also measure Lr1 when the secondary is short-circuited. I couldn't figure out that how to measure L1 in a real transformer. Yes, I can easily understand that K is coupling factor which is used to enter the N1/N2 to the simulation. But, my questions is that Do L1 & L2 values (400m and 1m) has any effect on LLC operation? Or, they are only used for determining turns ratios and they are not reflect any real circuit parameters? Thank you for your explanations in advance. Best regards,
@@volkansuel4910 In LTspice you could put literally any values, provided they are big, because that inductance here has to operate like an ideal trasformer. His role is not to store energy and to change at each cycle like the Lm magnetizing does, but to transfer energy to the secondary. Imagine a trasformer and it has a 2-3% of leakeage flux. That would be the Lr, so, all the other flux is transfered. If you want to measure the true L1, well, it won't even be important as long as you have the gain of your transformer You open there, short that, short this with that and bla bla and obtain the Gain But the L1 and L2? Not useful
Average model of active clamp forward coverter requires a tons of time and demonstration of maths and paper, in this period i'm quite occupied so I don't know if I will find the time to do that
Thanks for the video. I had a question about how the power flows from one bridge to another bridge when the same gate pulse is applied to both primary and secondary side switches. Could you please explain?
During the Turn On time, in which M1 and M4 are On the current will flow in the positive verse, from left to right in the tank llc. Then the current goes in the secondary side and will follow the same path of the diode (so the first mosfet on the top left will be on). Imagine to replace the passive diodes with the active mosfets. During Ton, M1 and M4 are on on the primary, and the other two mosfet are active on the secondary (Top left and bottom right) like the diode were active passively. I explained this in the video before designign the synch rectifier
@@manoA98A thank you sir. If both side MOSFETs are switched at same time , without any phase shift, whether power will flow? If power flows ,since both are bidirectional switch, power will flow from HV to LV or LV to HV? Kindly clarify my doubt sir.
@@rajeshsethuraman1383 If you ever design this converter in practice, there will actually be a time delay lag between the first bridge and the secondary one. It's not 100% simultaneuous. Plus, when dealing with HV and probably SiC device, there will be additional loss to the discharge of the Cds at each switching cycle which has to be taken in to account. Driver design and auxiliar power supply for the driver are not shown in this video. In real life you will need flyback or push pull to generate 15/20V for the power supply or your drivers, both used for the first and the second bridge
Did you now that Google sees the .dll files in your Buck converter directory as containing a virus ? I know they do not but Google does not like them. They don't like .exe files either and other extensions Thank you for this !
No, there are 2 DLL files in that one directory that also contains .CPP files which download just fine. When I choose either one or several files for my download in the ZIP file package, it even tells me that those 2 files could not be downloaded. Weird I know but probably not that weird for Google and Google Drive. Gmail also has limitations on what kinds of files are attached to an email. Great stuff you have there though ! I am happy with what you have done with LTspice. I have only started to use Qspice once or twice so far and it is nice you have some of that as well.
@@endremurti ZVS in the primary Is reached through the condition explained at the beginning of the video: Min. Dead time and magnetizing inductance which Is able to discharge the CDS of the mosfets
Full bridge LLC! Great video and explain .Thank you so much!
Hi Mano, thanks again for the great presentation!
@@longwang3271 You're welcome
One year ago I made a video about LLC, but it wasn't soft switching and the waveform were wrong.
This video is the correct version, sorry for that!
Hope you enjoyed
Great video! Thank you!
Thank you Leonardo da Vinci
@@markoalagic9857 Ahahaha Don't be silly! I am not even 1/10 of that man
Hallo Mano very good video with full insights , Looking forward for Simulation of Matrix converter in LT spice
Hi Mano,
I have bumped into your channel and I have been viewing in order full of your videos. I would like to say a special thank you for your great efforts.
My questions is that what are the differences between Lm1 and L1 in the transformer? Lm1 is participating resonant tank equations, and L1 is considered as transformer operation? In real LLC transformer, how can we extract/measure Lm1 and L1 by using LCR meter to distinguish their values?
Thanks in advance!
Hi! Thanks for your comment
So in order
To create a transformer in LTSPICE, you need two coupled inductors, hence L1 and L2. You need also the parameter K L1 L2 1 to ensure that L1 and L2 are magnetically coupled. If K is less than 1, you are modelling also non ideal coupling.
L1 and L2 are related to n^2, hence, if L1=400m and L2=1m, it means that the turn ratio of the transformer is 22
Input 1000V, Output 1000/22
Now Lm1 and Lr1, Lr2
Lm is the magnetizing inductance. In the LLC tank resonator, it has a pivotal role since it performes ZVS on the primary by changing energy with the Cds parasitic capacitance of the SiC mosfet of the primary Full Bridge. To do that, you need precise dead time. Hence Lm and Cr will be responsible for the ZVS on the primary. That's the first frequency.
Lr is the leakeage inductance. His role is mainly to give the series resonant frequency for the ZCS (not ZVS, take care) of the secondary synchronous bridge. The current will be modulated by this series LC to make the current go to zero naturally before the mosfet starts commutating.
Now, how to measure them
You use instruments like Bode 100 and study the primary impedeance, and with some heavy formulas, extract the parameter. Trust me on this, it's a job I am doing, as a Power Electronic Hardware Designer. Fun for the first 10 minutes, heavy after a month.
Feel free to ask
@@manoA98A Thank you for your quick response. I really really appreciate it.
It sound silly but I am still having a little confusion here for Lm1 and L1.
I could measure Lm1 when the secondary is open-circuited by Bode100 or LCR meter.
I could also measure Lr1 when the secondary is short-circuited.
I couldn't figure out that how to measure L1 in a real transformer.
Yes, I can easily understand that K is coupling factor which is used to enter the N1/N2 to the simulation. But, my questions is that Do L1 & L2 values (400m and 1m) has any effect on LLC operation? Or, they are only used for determining turns ratios and they are not reflect any real circuit parameters?
Thank you for your explanations in advance.
Best regards,
@@volkansuel4910 In LTspice you could put literally any values, provided they are big, because that inductance here has to operate like an ideal trasformer. His role is not to store energy and to change at each cycle like the Lm magnetizing does, but to transfer energy to the secondary.
Imagine a trasformer and it has a 2-3% of leakeage flux. That would be the Lr, so, all the other flux is transfered.
If you want to measure the true L1, well, it won't even be important as long as you have the gain of your transformer
You open there, short that, short this with that and bla bla and obtain the Gain
But the L1 and L2? Not useful
Thanks for your reply
How would you now integrate a close loop control in LTSpice? Basically adjusting the switching frequency with changing input voltage and load steps?
Very good explain
Hi, love the video. Can u explain how u got the LLC-tank values? Im following the Infinion design guide and it does not match at all :/
@@maxi4539 These values are from my trasformer that I use in my Company. I can't say more Because it's confidential and I Risk much. Sorry.
How to see the output voltage Bode plot of LLC?
Hey can you explain how to find maximum power at different switching frequency? And even if the load is not same like varying load?
Hello Mano...great video ....could you please make video on average model/small signal model of active clamp forward converter?
Average model of active clamp forward coverter requires a tons of time and demonstration of maths and paper, in this period i'm quite occupied so I don't know if I will find the time to do that
Thanks for the video. I had a question about how the power flows from one bridge to another bridge when the same gate pulse is applied to both primary and secondary side switches. Could you please explain?
During the Turn On time, in which M1 and M4 are On the current will flow in the positive verse, from left to right in the tank llc. Then the current goes in the secondary side and will follow the same path of the diode (so the first mosfet on the top left will be on). Imagine to replace the passive diodes with the active mosfets. During Ton, M1 and M4 are on on the primary, and the other two mosfet are active on the secondary (Top left and bottom right) like the diode were active passively. I explained this in the video before designign the synch rectifier
@@manoA98A thank you sir.
If both side MOSFETs are switched at same time , without any phase shift, whether power will flow?
If power flows ,since both are bidirectional switch, power will flow from HV to LV or LV to HV?
Kindly clarify my doubt sir.
@@rajeshsethuraman1383 If you ever design this converter in practice, there will actually be a time delay lag between the first bridge and the secondary one. It's not 100% simultaneuous. Plus, when dealing with HV and probably SiC device, there will be additional loss to the discharge of the Cds at each switching cycle which has to be taken in to account. Driver design and auxiliar power supply for the driver are not shown in this video. In real life you will need flyback or push pull to generate 15/20V for the power supply or your drivers, both used for the first and the second bridge
@@manoA98A thank you very much sir
Did you now that Google sees the .dll files in your Buck converter directory as containing a virus ? I know they do not but Google does not like them. They don't like .exe files either and other extensions
Thank you for this !
Woh, really? They are Just Spice files lol
No, there are 2 DLL files in that one directory that also contains .CPP files which download just fine. When I choose either one or several files for my download in the ZIP file package, it even tells me that those 2 files could not be downloaded. Weird I know but probably not that weird for Google and Google Drive. Gmail also has limitations on what kinds of files are attached to an email.
Great stuff you have there though ! I am happy with what you have done with LTspice. I have only started to use Qspice once or twice so far and it is nice you have some of that as well.
Is this a Full bridge ?
Yes
Very nice, how the signal of the full bridge produce zvs ? Runing phase shifted or how
@@endremurti ZVS in the primary Is reached through the condition explained at the beginning of the video: Min. Dead time and magnetizing inductance which Is able to discharge the CDS of the mosfets