Now that I am an old man well above 80, retired from working as an engineer, I have time to ponder and philosophize about my past. Listening to the great details and intricacies and activity inside the various electronic circuits depicted by Sam Ben- Yaakov reminds me of the many heated arguments I had with my linguists and artists and religious " socially emotional" colleagues, who criticized me whenever I described my practical electronic circuits as being, " so nice and beautiful and so poetic and so exact and elegant in their rhythmic, synchronized and phased operations, as if a musical piece was being played, while the currents and voltages, always dance in pairs at different orientations, to the beat of the elements in the circuit, which has its own soul and spirit at every location in the array of connected components. " My learned colleagues always said that one cannot use such emotional language when dealing with silent and unseen electronics activities, where all that one can say about them is, that the circuits are "useful and operational" but not "pretty" and "beautiful" and "poetic". nor " artistic" in their nature. Somehow they were only sensitive to social emotions and not the rhythm of the natural universe! The use of his frequency to voltage conversion for automatic gain control reminds me of Frequency modulation and how the resonant circuit is used offset, on either side to change frequency to the magnitude to do what one requires with it, but one side is preferable for technical convenience. This FM demodulator circuit is related to the one that was invented by Dudley E. Foster and Stuart William Seeley in 1936. Although it was originally intended as a circuit to provide automatic frequency control, it was more widely used as an FM demodulator, whilst also being able to provide a voltage for automatic frequency control. In my youth, I used to build my own phase-locked loop to lock two frequencies together, and in my switched servos operating on pulse width positional control, one needed to compare pulses and change the information from phase overlap to voltage with an XOR gate used as a switching or pulse train error detector, to then operate the motors or the variable frequency oscillator. These last two days, I have got drunk and certainly intoxicated myself with many of San Ben Yaakov videos and their detailed explanations, and I am thinking whether there was any manner in which my past, where my literary, linguists and artistic and religious and political and legal and medical colleagues could ever gain any level of technical sensitivity and selectivity to tune and recognize the souls and spirits existing in our electronic circuits and the music and the beautiful moves, as in this case, obtained by staying off-resonance of a tuned circuit. It is a remarkable human feat associated with developing the sensitivity of feeling for those various voltages, located at different nodes, periodically extending their long arms into the four corners of that full switching bridge and the importance associates with the hesitation and pausing till that natural moment when the inherent rhythm, of the rate of rising of voltages to the switching sequence, is just right to operate any of Q1, Q2, Q3, and Q4. with zero voltage across them. Operating one transistor at a time AT THE RIGHT MOMENT related to the natural rate of change of those various voltage variations seems to obtain the right swinging music to achieve a smoother soothing action in that circuit. Ben, should know that I compare him with a brilliant musical conductor dealing with the electronic components in a philharmonic orchestra, where he certainly knows what each player in that orchestrating circuit can play. He may only have L, C, R, Voltage and Current sources, a few diodes and transistors of all types, but he can certainly feel the music they play right in his heart. Congratulations on your dedicated efforts in depicting the beauty within the soul and spirit of our electronics. Wish Ben had a larger hall ( whiteboard) to write and play his music on! To think that it is electronic circuits that are playing this submitted video makes the heart of an old engineer, beat a little faster, but it would leave all my past colleagues cold and unmoved by that idea. Ben Yaakov, Prosit. Now that we are close to Christmas festivities and New Year, I can propose a toast. May you have a good Christmas and a Healthy new year to proceed with your sublime electronic explanations for the good of our young people who need to know the soul and spirit and the rhythms of the gems of engineering in all their brilliant facets. Ben's video is not any different from the contents of the following video th-cam.com/video/aj_E1hD876c/w-d-xo.html th-cam.com/video/NI3fTby-dko/w-d-xo.html
Dear Carmel. First and foremost, 80 years is not old, I should know😊Thank you very much for sharing your thoughts. Ever since I was experimenting with electricity as a kid (did you know that when you connect steel wool to the tabs of the vintage 6volt battery, it will ignite? I found it out when I was a bout 5 years old) I was fascinated with the beauty of electronics and stunned by its magic. Even now, after umpteen years of experience, I ma amazed to see a physical circuit working when built according to a sketch and back of the envelop calculation. I am not a religious person, but certainly temped. Thanks for the warm words and I wish to both of us many years of creation and watching of videos.
@@sambenyaakov I did push wires in a wall outlet when I was that old, getting big punishment of the parents. Dear Carmel, it is not age who make you old, it's all about how you feel, good genes and a lot of joy keeps someone running important is stay moving around keep you young, so on a bicycle and walking from time to time...
Great explanation... very clear and precise... not too fast, not too technical... very good! I learned a lot in this one video, and I've been in electronics for 40 years.
Thanks. Welcome to watch other videos in my TH-cam channel and join LinkedIn group th-cam.com/users/sambenyaakovvideos www.linkedin.com/groups/13606756
Thank you, Prof. Sam for this beautifully explained lecture. Its clear my following doubt: 1) Effect of harmonic content of input square wave 2) Leading vs lagging operating range 3) Why LLC preferred compare to LC
Thanks for note, I believe 1 and 2 are explained in video. Point 3 is discussed in th-cam.com/video/tCEqm-RoP20/w-d-xo.html . For more information on LLC, look for "sam ben-yaakov LLC" in TH-cam search window.
Really great explanation of the basic conceps of resonant converters. Obtaining mathematical expressions of the non linear and square wave circuit is very complex. I like that you clarly reasoned how to turn this complex problem into a handful circuit that can be manipulated. Thank you.
@@sambenyaakov Dear Dr. Yaakov, You might find the flying machine on my channel interesting. I'm trying to get its resonant Royer to run on 12V instead of about 7V. I know the frequency will go up so I will try increasing C1 to bring it back down. I don't really understand the waveform of the resonance coil that drives the transistor bases either. I'd like to be sure its op voltage is in a healthy range to drive the transistors. I thought winding it with 1 less turn might be a good idea.
THANK YOU FOR THIS MORE EXPLANATION, LIKE EVERYONE WHO HAS ALREADY WATCHED IS PERFECTLY DIDATICALLY PLEASE, CONTINUE THAT YOUR JOB God bless you ENG ° LUIZ ALVES RIO DE JANEIRO BRAZIL
I actually built this topology of converter before even knowing what about it "academically"! So I'm happy to learn about it! I built a Tesla coil with a primary coil in series with a bunch of film capacitors with the primary tuned to the frequency of the secondary, around 300kHz, I got the idea learning that series LC circuit has ZERO impedance at resonance, so to get maximum power transfer, since FET's have very low Rds(on), I should a series LC network and use a phase locked loop (CD4046) to lock on and ram as much current as I possibly can at a given can into the primary and let the voltage at the node between L and C climb unbounded. :) I am now able to dump over 500W into the secondary with a full bridge, and my FETs don't get too hot :D It still needs lots of work. My PCB layout has issues and my FET's keep dying especially if something causes the circuit to fall out of resonance and switch at a lower frequency. Still trying to identify the root cause. I did observe 1.8x voltage in ringing at 40MHz, which might be the culprit. Also it is strenuous on the capacitor and even my secondary as it heats up noticably. Had to buy the lowest dissipation capacitors I could find on LCSC and put lots of them in series/parallel. But as of now my biggest limit is really my 48V 7.5A mean-well SMPS that apparently can output 55V at >10A before shutting down due to overcurrent.
@@sambenyaakov Thank you so much for your reply! I my HY1920P tend to fail with a short between gate and drain, causing them to behave a lot like 4 volt zener diodes, since the channel still works. I have a very low impedance gate drive of [0 - 12v] and minimized the trance length to a couple centimeters thinking Vgs > 20V was the cause. However after looking at the Vgs on a scope I don't think this is the problem. What else could cause a short between gate and drain whist the channel continues to work fine?
A blown gate is indeed normally due to over voltage of Vgs. Do you have a wide BW scope? it takes a very short pulse to do the damage. Try to put a 10nF cap right oh G_S terminals just for testing.
@@sambenyaakov Here is a photo gallery of images when I asked on reddit. i.imgur.com/v8NjNin.jpg I have since shortened the twisted pairs by moving the driver IC closer to the PCB. you can see I added a 12V zener to the gate/source to clamp the voltage to [0 - 12v]. Probing using the springy contact with a 100MHz scope w/ no bandwidth limit. Here is the result i.imgur.com/037HrTd.jpg
I thank you a lots Sir; it is really helpful video especially for beginners like me. i will really appreciate if you provide me with related and basic references that include mathematical proofs of mentioned equations. many thanks once again.
hello prof.sam,and congratulations for your video..im building a resonant,full bridge step up dc-dc converter 12to 240 volts 1000w power,and i want ask what resonant topology souhld i choose?..the frequency is 50000hz..thank you .
Hi Professor, I have a question. At 17:50, since the current is lagged, at turn on of Q4, the current will raise after VDS4 drops to 0. Is this example also ZCS at turn on of Q4?
Thank you for this clear explanation. A practical thing that i do not understand is, how the resonant frequency and switching frequency should stand in propotion. What is the ideal distance of both frequencies and what should be determined First?
Okay, if i use the leakage inductance from main transformer+ external serial inductor and the parasitic output capacitance of the MOSFETs to take this energy for ZVS it is not possible to have a switching frequency above the resonance frequency (MHz) because its too high with those values. Nevertheless it seems that ZVS is archievable with a legging current. I dont Unterstand why the current is still lagging if i am below the resonant frequency.
Hello Prof Ben-Yaakov, Would you be able to add (or explain) more on "Self-Contained Resonant Rectifier for Piezoelectric Sources'" , would love to understand some of the principle of Operation you discussed about on Sec III of your a paper from 2011 on this topic (Self-Contained Resonant Rectifier for Piezoelectric Sources Under Variable Mechanical Excitation). Thank you so much in Advance!
Thank you Prof. Sam for the wonderful explanation of the operation. I was wondering how to come up with a new resonant circuit for ZVS or ZCS? Can you please shed some light on that.
14:02 why is a series inductance necessary once you add a transformer? don't transformer primaries already have an inductance that is exploited when building the typical flyback topology converters? I have always thought of a flyback topology as being sort of an extension of a boost converter.
The xternal inductance designated both leakage inductance and /or an external inductor. Using the leakage inductor (which you ca adjust by design) may lead to increased power loss.
@@sambenyaakov thank you sir, for video link, i have seen it, according to this video we need LISN to estimate about the concucted emission, so from LISN data we design the EMC filter, is there any mathematical literature to estimate this CE without using LISN, because for high power DUT , LISN should satisfy the DUT current and voltage rattings, which may be expensive
Hi Professor Sam, If the switches are controlled by feedback from the resonant circuit itself, as opposed to external control, do they still actually operate slightly above the resonant point, or do they actualyl turn on and off exactly at the resonant frequency?
Dear Professor Yaakov, In the Galvanically isolated version, is it possible to eliminate the inductor by using the transformer as a shared inductor ? If load changes, with time, how do we maintain a constant output voltage ?
Hello sir! Your video is amazing but I have a little confusion, at 11:20 minutes there are two formulas written for Re and RL, according to my calculations they should be like "R=[(pi^2)/8]Re" & "Re=[8/(pi^2)]R". Please help if I am doing it wrong even a small hint will be of great use.
Thanks so much ,you are amazing, it is possible please to explain LLC and LCC converter and also how we can achieve higher efficiency by controlling our timing of the MOSFET or can I recommend me what to read to be able to understand it?
@Sam Ben-Yaakov Sir I have one doubt at the output side of the rectifier , you assumed that an unidirectional sinusoidally varying Output Voltage is produced so Its average output voltage will be (2*Vm/pi).So the load power will be (4*Vm^2)/(pi^2*RL).Since we are considering only the fundamental Harmonics associated with the transformer secondary side voltage , its rms value will be ,Vrms=Vm/sqrt(2).So the power supplied by the transformer is pac=Vrms^2/Rac where Rac is the equivalent resistance seen at the input terminals of the bridge rectifier. Equating these two(load power and source power) we get the value of the ac equivalent resistance as ,Rac=RL*(8/pi^2).Sir my doubt is because of the presence of capacitor at the output of the full bridge rectifier, The output voltage will be moreover a straight DC with some ripples in it. The value will be moreover equal to the maximum value of the fundamental value of the voltage across the transformer secondary side terminals. So approximately Equating Vdc to Vm. So the power across the load will be (Vm^2/RL).Since the input real power from the transformer secondary side is Vrms^2/Rac . Here Vrms=Vm/sqrt(2).Equating these two power by assuming ideal conditions and solving in the similar way we are getting RL/2=Rac . Sir is my point valid if I am wrong please correct me sir. Thank you
Thanks for not. "The value will be moreover equal to the maximum value of the fundamental value of the voltage across the transformer secondary side terminals." Incorrect. This is NOT the case of a VOLTAGE SOURCE feeding a cap via a diode. The cap voltage is the average voltage in this case.
@@sambenyaakov Thank you professor 😃😃.Sir one more small request, I need a material for finding the control transfer function inorder to make the resonant converter operate in Closed Loop thereby achieving a voltage regulation at the load side. Can you teach us how to arrive at that control transfer function sir.
A very good tutorial Prof. Sam Ben-Yaakov. I have a specific question regarding DC-DC converter for a particular configuration. I have an isolated dc-dc SRC ( Vinput=100 V, Voutput=300V, Output power=300W). What can be the potential applications as per existing industrial practices in the renewable sector best suited to the mentioned input and output configurations? I would be happy to get guidance on the available products in the market. Thank you for your time.
Rewatching the video to refresh my mind, on the ZVS part, is it possible that the MOSFET drain-source capacitance can be used as the resonant capacitor?
The D-S capacitance helps to provide ZVS at turn off by slowing down the rate of rise of the voltage. I do not recall seeing anyone using them as the resonant capacitors. For one thing, the are extremely non linear (voltage dependent) so there is a problem already there.
Hi Sam. Low magnetizing current. Z(Lm) is much bigger than the load impedance. Can you trow a bone here, what is the proper impedance of the LCC resonance transformer, I can calculate this Z and know the LCC resonance tank is a current source, so load impedance for that is high, a to low inductance of primary will load the source such it does not work well. I have use 1mH and above for that, 500 uH by the way is also workable, but I did simulate with 1mH. 500 uH on 100 Khz give 314 reactance, and 1mH double that. But saw LCC designs with 5mH giving a reactance of more then 3 kilo ohm. Making the inductance to high then I think losses get involved, but also the windings do not fit anymore on the core, we need to fill that but not to much. this week I get the precision caps for the meter, then I can start building a test version. regards
Why do we use a coupling capacitor along with a transformer in the "current driven rectifier" of a resonant LLC converter ?? Could you pls share some thoughts. Thank you
Sir at 18:06 , how Q3 body diode conducts even if voltage on the line and drain of Q3 are at same potential ? I understood because of lagging nature of circuit the current is starting slow and switching losses are reduced
@@sambenyaakov Sir , I meant how body diode was conducting from the point other than line(Vin) of MOSFET Q3 to line(Vin) ; Is it because of Capacitance of 1st and 4th MOSFETS
@@sambenyaakov please sir,i was wondering if you can tell me how we can achieve ZVS in LLC converter with GaN half bridge topology and GaN don't have a body diode,so where does current flow to make voltage across the device zero before turn it on.thank you
@@sambenyaakovBut sir if we minimize the dead time ZVS transition will not take place and we are in case if hard switching and losses will increase,i'm designing an LLC with high efficiency above 98%,that is why i should focus on losses.
Dear Sir Sam! i have read other articles and conducted experiments,and i doubt that transistors can have soft swithcing during turn off as you stated in your video. yes,they are turned on softly,but not turned off. can you give me some evidences that iam wrong?
Thanks for comment. Firstly, lets clarify a possible misunderstanding: 'turn off' refers to the current of the transistor (Vds is rising). 'Turn off' snubbers, resonant converters, phase shift PWM and others are widely used in the industry to achieve pseudo ZVS (slowing down dv/dt of Vds). There are literary hundreds if not thousands of papers and application notes on that .
I mean we have buck, boost and buck boost with soft switcings then again we are using resonant converters in some applications, why ???? that's my question sir.
Now that I am an old man well above 80, retired from working as an engineer, I have time to ponder and philosophize about my past. Listening to the great details and intricacies and activity inside the various electronic circuits depicted by Sam Ben- Yaakov reminds me of the many heated arguments I had with my linguists and artists and religious " socially emotional" colleagues, who criticized me whenever I described my practical electronic circuits as being, " so nice and beautiful and so poetic and so exact and elegant in their rhythmic, synchronized and phased operations, as if a musical piece was being played, while the currents and voltages, always dance in pairs at different orientations, to the beat of the elements in the circuit, which has its own soul and spirit at every location in the array of connected components. " My learned colleagues always said that one cannot use such emotional language when dealing with silent and unseen electronics activities, where all that one can say about them is, that the circuits are "useful and operational" but not "pretty" and "beautiful" and "poetic". nor " artistic" in their nature. Somehow they were only sensitive to social emotions and not the rhythm of the natural universe!
The use of his frequency to voltage conversion for automatic gain control reminds me of Frequency modulation and how the resonant circuit is used offset, on either side to change frequency to the magnitude to do what one requires with it, but one side is preferable for technical convenience. This FM demodulator circuit is related to the one that was invented by Dudley E. Foster and Stuart William Seeley in 1936. Although it was originally intended as a circuit to provide automatic frequency control, it was more widely used as an FM demodulator, whilst also being able to provide a voltage for automatic frequency control.
In my youth, I used to build my own phase-locked loop to lock two frequencies together, and in my switched servos operating on pulse width positional control, one needed to compare pulses and change the information from phase overlap to voltage with an XOR gate used as a switching or pulse train error detector, to then operate the motors or the variable frequency oscillator.
These last two days, I have got drunk and certainly intoxicated myself with many of San Ben Yaakov videos and their detailed explanations, and I am thinking whether there was any manner in which my past, where my literary, linguists and artistic and religious and political and legal and medical colleagues could ever gain any level of technical sensitivity and selectivity to tune and recognize the souls and spirits existing in our electronic circuits and the music and the beautiful moves, as in this case, obtained by staying off-resonance of a tuned circuit. It is a remarkable human feat associated with developing the sensitivity of feeling for those various voltages, located at different nodes, periodically extending their long arms into the four corners of that full switching bridge and the importance associates with the hesitation and pausing till that natural moment when the inherent rhythm, of the rate of rising of voltages to the switching sequence, is just right to operate any of Q1, Q2, Q3, and Q4. with zero voltage across them. Operating one transistor at a time AT THE RIGHT MOMENT related to the natural rate of change of those various voltage variations seems to obtain the right swinging music to achieve a smoother soothing action in that circuit.
Ben, should know that I compare him with a brilliant musical conductor dealing with the electronic components in a philharmonic orchestra, where he certainly knows what each player in that orchestrating circuit can play. He may only have L, C, R, Voltage and Current sources, a few diodes and transistors of all types, but he can certainly feel the music they play right in his heart. Congratulations on your dedicated efforts in depicting the beauty within the soul and spirit of our electronics. Wish Ben had a larger hall ( whiteboard) to write and play his music on!
To think that it is electronic circuits that are playing this submitted video makes the heart of an old engineer, beat a little faster, but it would leave all my past colleagues cold and unmoved by that idea. Ben Yaakov, Prosit. Now that we are close to Christmas festivities and New Year, I can propose a toast. May you have a good Christmas and a Healthy new year to proceed with your sublime electronic explanations for the good of our young people who need to know the soul and spirit and the rhythms of the gems of engineering in all their brilliant facets. Ben's video is not any different from the contents of the following video
th-cam.com/video/aj_E1hD876c/w-d-xo.html
th-cam.com/video/NI3fTby-dko/w-d-xo.html
Dear Carmel. First and foremost, 80 years is not old, I should know😊Thank you very much for sharing your thoughts. Ever since I was experimenting with electricity as a kid (did you know that when you connect steel wool to the tabs of the vintage 6volt battery, it will ignite? I found it out when I was a bout 5 years old) I was fascinated with the beauty of electronics and stunned by its magic. Even now, after umpteen years of experience, I ma amazed to see a physical circuit working when built according to a sketch and back of the envelop calculation. I am not a religious person, but certainly temped. Thanks for the warm words and I wish to both of us many years of creation and watching of videos.
@@sambenyaakov I did push wires in a wall outlet when I was that old, getting big punishment of the parents. Dear Carmel, it is not age who make you old, it's all about how you feel, good genes and a lot of joy keeps someone running important is stay moving around keep you young, so on a bicycle and walking from time to time...
Great explanation... very clear and precise... not too fast, not too technical... very good! I learned a lot in this one video, and I've been in electronics for 40 years.
Thanks. Welcome to watch other videos in my TH-cam channel and join LinkedIn group
th-cam.com/users/sambenyaakovvideos
www.linkedin.com/groups/13606756
Outstanding tutorial, the best so far. Please keep them coming.
Thank you, Prof. Sam for this beautifully explained lecture. Its clear my following doubt:
1) Effect of harmonic content of input square wave
2) Leading vs lagging operating range
3) Why LLC preferred compare to LC
Thanks for note, I believe 1 and 2 are explained in video. Point 3 is discussed in th-cam.com/video/tCEqm-RoP20/w-d-xo.html . For more information on LLC, look for "sam ben-yaakov LLC" in TH-cam search window.
Simple and intuitive explanation. thanks professor
Thanks for comment.
Thank you Prof. Yaakov you have explained a complex topic in a very easy way to understand....
Thanks for comment.
Wonderful presentation, thank you. Extremely intuitive, immediately getting to the gist of essential aspects without a lot of digression.
🙂👍
Absolutely. Very good presentation on the subject.
Very helpful and natural
Respect from India Sir.
Thanks
The first good lecture I found on this topic!
🙏😊
@@sambenyaakov Sir. I want to understand LLC in greater detail. Could you please point me to a good source?
Really great explanation of the basic conceps of resonant converters.
Obtaining mathematical expressions of the non linear and square wave circuit is very complex. I like that you clarly reasoned how to turn this complex problem into a handful circuit that can be manipulated. Thank you.
Thanks for king note.
very informative! thank you very much Prof.Sam
😊
Спасибо! Вы очень ясно все объясняете.
As a beginner, your lecture open my mind about harmonic wave as you mention 1rst, 3trd, 5th, 7th and so on. Thank a lot Prof. Sam
👍😊
Thank you for your practical explanation. I can clearly understand about ZVS.
Thanks for comment.
Thanks for your good lesson professor, as an engineer it was very helpful.
Thanks for comment.
Thank you a lot!!! This question bothers me quite a long time but your explanation is quite clear!!!
👍Thanks
Very clear presentation and easy to following. Thy Pof. Sam
Thanks
this video in particular was very good
Thanks
Its an amazing lecture sir...I am thankful to you ....
😊
Thank you for sharing.
Thank you Sam! Great food for thought!
Thanks
@@sambenyaakov
Dear Dr. Yaakov,
You might find the flying machine on my channel interesting. I'm trying to get its resonant Royer to run on 12V instead of about 7V. I know the frequency will go up so I will try increasing C1 to bring it back down. I don't really understand the waveform of the resonance coil that drives the transistor bases either. I'd like to be sure its op voltage is in a healthy range to drive the transistors. I thought winding it with 1 less turn might be a good idea.
Thank you a lots prof. it really helps.
Thanks
THANK YOU FOR THIS MORE EXPLANATION, LIKE EVERYONE WHO HAS ALREADY WATCHED IS PERFECTLY DIDATICALLY
PLEASE, CONTINUE THAT YOUR JOB
God bless you
ENG ° LUIZ ALVES
RIO DE JANEIRO
BRAZIL
Thanks
I actually built this topology of converter before even knowing what about it "academically"! So I'm happy to learn about it!
I built a Tesla coil with a primary coil in series with a bunch of film capacitors with the primary tuned to the frequency of the secondary, around 300kHz, I got the idea learning that series LC circuit has ZERO impedance at resonance, so to get maximum power transfer, since FET's have very low Rds(on), I should a series LC network and use a phase locked loop (CD4046) to lock on and ram as much current as I possibly can at a given can into the primary and let the voltage at the node between L and C climb unbounded. :)
I am now able to dump over 500W into the secondary with a full bridge, and my FETs don't get too hot :D It still needs lots of work. My PCB layout has issues and my FET's keep dying especially if something causes the circuit to fall out of resonance and switch at a lower frequency. Still trying to identify the root cause. I did observe 1.8x voltage in ringing at 40MHz, which might be the culprit. Also it is strenuous on the capacitor and even my secondary as it heats up noticably. Had to buy the lowest dissipation capacitors I could find on LCSC and put lots of them in series/parallel.
But as of now my biggest limit is really my 48V 7.5A mean-well SMPS that apparently can output 55V at >10A before shutting down due to overcurrent.
Hi , Wow it sound you have a lot of fun.Thanks for sharing. Is there any specific question I can help with?
@@sambenyaakov Thank you so much for your reply! I my HY1920P tend to fail with a short between gate and drain, causing them to behave a lot like 4 volt zener diodes, since the channel still works. I have a very low impedance gate drive of [0 - 12v] and minimized the trance length to a couple centimeters thinking Vgs > 20V was the cause. However after looking at the Vgs on a scope I don't think this is the problem. What else could cause a short between gate and drain whist the channel continues to work fine?
A blown gate is indeed normally due to over voltage of Vgs. Do you have a wide BW scope? it takes a very short pulse to do the damage. Try to put a 10nF cap right oh G_S terminals just for testing.
@@sambenyaakov Here is a photo gallery of images when I asked on reddit. i.imgur.com/v8NjNin.jpg
I have since shortened the twisted pairs by moving the driver IC closer to the PCB. you can see I added a 12V zener to the gate/source to clamp the voltage to [0 - 12v]. Probing using the springy contact with a 100MHz scope w/ no bandwidth limit. Here is the result i.imgur.com/037HrTd.jpg
The impedance of gate driver at turn off does not seem low enough and... you might have faulty transistors
very nice explanation sir..thanks a lot..
Thank you for comment
very useful. thanks
Thanks
Thank you sir. It was really helpful
😊🙏
Thank your Sir!
😊
Thanks alot
thank u too prof. Yaakov
😊
I thank you a lots Sir; it is really helpful video especially for beginners like me. i will really appreciate if you provide me with related and basic references that include mathematical proofs of mentioned equations. many thanks once again.
Look up the Power Electronics book by Erikson and Maksimovitz
hello prof.sam,and congratulations for your video..im building a resonant,full bridge step up dc-dc converter 12to 240 volts 1000w power,and i want ask what resonant topology souhld i choose?..the frequency is 50000hz..thank you .
The RL to Re reflection is flipped. It should be 8/Pi^2 not Pi^2/8. I'm guessing its a typo.
Sure. Thanks for observation and pointing out the typo.
Hi Professor,
I have a question. At 17:50, since the current is lagged, at turn on of Q4, the current will raise after VDS4 drops to 0. Is this example also ZCS at turn on of Q4?
Thank you for this clear explanation. A practical thing that i do not understand is, how the resonant frequency and switching frequency should stand in propotion. What is the ideal distance of both frequencies and what should be determined First?
The required gain determines the shift, you would like to stay above resonant for ZVS
Okay, if i use the leakage inductance from main transformer+ external serial inductor and the parasitic output capacitance of the MOSFETs to take this energy for ZVS it is not possible to have a switching frequency above the resonance frequency (MHz) because its too high with those values. Nevertheless it seems that ZVS is archievable with a legging current. I dont Unterstand why the current is still lagging if i am below the resonant frequency.
Hello Prof Ben-Yaakov, Would you be able to add (or explain) more on "Self-Contained Resonant Rectifier for Piezoelectric Sources'" , would love to understand some of the principle of Operation you discussed about on Sec III of your a paper from 2011 on this topic (Self-Contained Resonant Rectifier for Piezoelectric
Sources Under Variable Mechanical Excitation). Thank you so much in Advance!
Thank you Prof. Sam for the wonderful explanation of the operation. I was wondering how to come up with a new resonant circuit for ZVS or ZCS? Can you please shed some light on that.
You mean ZVS or ZCS?
@@sambenyaakov Lets say ZVS.
Dear professor, thank you for the excellent presentation. Could you please explain " PFM control for LLC.
This might be of help th-cam.com/video/amRqIgH10Rg/w-d-xo.html
Hi Professor, Thanks for your explanation. where I can find the mathematical proof of the relationship between Re and R l?
See papaer title at th-cam.com/video/R9GWfbLiy8g/w-d-xo.html
Once Q4 is off the capacitance of Q3 will be distarched and not charged. Hopefully my understanding is correct
Thanks for input. Please indicate which minute of video or slide number are you referring to.
14:02 why is a series inductance necessary once you add a transformer? don't transformer primaries already have an inductance that is exploited when building the typical flyback topology converters? I have always thought of a flyback topology as being sort of an extension of a boost converter.
The xternal inductance designated both leakage inductance and /or an external inductor. Using the leakage inductor (which you ca adjust by design) may lead to increased power loss.
thank you sir for your videos, Sir please make a video on EMC EMI line filter design for series resonant converter.
Have you seen: th-cam.com/video/5NRiLOvmXdA/w-d-xo.html
@@sambenyaakov thank you sir, for video link, i have seen it, according to this video we need LISN to estimate about the concucted emission, so from LISN data we design the EMC filter, is there any mathematical literature to estimate this CE without using LISN, because for high power DUT , LISN should satisfy the DUT current and voltage rattings, which may be expensive
Hi Professor Sam, If the switches are controlled by feedback from the resonant circuit itself, as opposed to external control, do they still actually operate slightly above the resonant point, or do they actualyl turn on and off exactly at the resonant frequency?
If the switch operation is derived from internal signal, say resonant current, this will be an oscillator with no control.
Dear Professor Yaakov, In the Galvanically isolated version, is it possible to eliminate the inductor by using the transformer as a shared inductor ? If load changes, with time, how do we maintain a constant output voltage ?
1. You can use a transformer.. 2. The control is by frequency variation.
Hello sir! Your video is amazing but I have a little confusion, at 11:20 minutes there are two formulas written for Re and RL, according to my calculations they should be like "R=[(pi^2)/8]Re" & "Re=[8/(pi^2)]R". Please help if I am doing it wrong even a small hint will be of great use.
see th-cam.com/video/-P-tDMr50mk/w-d-xo.html
looks like Pi/2*2⁰.⁵ is inversed
Hi Eduard, You are correct, one of the equation is in error. Thanks for pointing this out.
Thanks so much ,you are amazing, it is possible please to explain LLC and LCC converter and also how we can achieve higher efficiency by controlling our timing of the MOSFET or can I recommend me what to read to be able to understand it?
Thanks for the comment. The LLC and LCC are in queue.
@Sam Ben-Yaakov Sir I have one doubt at the output side of the rectifier , you assumed that an unidirectional sinusoidally varying Output Voltage is produced so Its average output voltage will be (2*Vm/pi).So the load power will be (4*Vm^2)/(pi^2*RL).Since we are considering only the fundamental Harmonics associated with the transformer secondary side voltage , its rms value will be ,Vrms=Vm/sqrt(2).So the power supplied by the transformer is pac=Vrms^2/Rac where Rac is the equivalent resistance seen at the input terminals of the bridge rectifier. Equating these two(load power and source power) we get the value of the ac equivalent resistance as ,Rac=RL*(8/pi^2).Sir my doubt is because of the presence of capacitor at the output of the full bridge rectifier, The output voltage will be moreover a straight DC with some ripples in it. The value will be moreover equal to the maximum value of the fundamental value of the voltage across the transformer secondary side terminals. So approximately Equating Vdc to Vm. So the power across the load will be (Vm^2/RL).Since the input real power from the transformer secondary side is Vrms^2/Rac . Here Vrms=Vm/sqrt(2).Equating these two power by assuming ideal conditions and solving in the similar way we are getting RL/2=Rac . Sir is my point valid if I am wrong please correct me sir. Thank you
Thanks for not. "The value will be moreover equal to the maximum value of the fundamental value of the voltage across the transformer secondary side terminals." Incorrect. This is NOT the case of a VOLTAGE SOURCE feeding a cap via a diode. The cap voltage is the average voltage in this case.
@@sambenyaakov Thank you professor 😃😃.Sir one more small request, I need a material for finding the control transfer function inorder to make the resonant converter operate in Closed Loop thereby achieving a voltage regulation at the load side. Can you teach us how to arrive at that control transfer function sir.
A very good tutorial Prof. Sam Ben-Yaakov. I have a specific question regarding DC-DC converter for a particular configuration. I have an isolated dc-dc SRC ( Vinput=100 V, Voutput=300V, Output power=300W). What can be the potential applications as per existing industrial practices in the renewable sector best suited to the mentioned input and output configurations? I would be happy to get guidance on the available products in the market. Thank you for your time.
This might fit the case of a PV panel for 110VAC appliances if a DC-AC inverter will be added.
Thank you very much for your reply Prof. Sam Ben-Yaakov.
Rewatching the video to refresh my mind, on the ZVS part, is it possible that the MOSFET drain-source capacitance can be used as the resonant capacitor?
The D-S capacitance helps to provide ZVS at turn off by slowing down the rate of rise of the voltage. I do not recall seeing anyone using them as the resonant capacitors. For one thing, the are extremely non linear (voltage dependent) so there is a problem already there.
Hi Sam. Low magnetizing current. Z(Lm) is much bigger than the load impedance. Can you trow a bone here, what is the proper impedance of the LCC resonance transformer, I can calculate this Z and know the LCC resonance tank is a current source, so load impedance for that is high, a to low inductance of primary will load the source such it does not work well. I have use 1mH and above for that, 500 uH by the way is also workable, but I did simulate with 1mH. 500 uH on 100 Khz give 314 reactance, and 1mH double that. But saw LCC designs with 5mH giving a reactance of more then 3 kilo ohm. Making the inductance to high then I think losses get involved, but also the windings do not fit anymore on the core, we need to fill that but not to much.
this week I get the precision caps for the meter, then I can start building a test version.
regards
See th-cam.com/video/ZWwZBHV0ynY/w-d-xo.html
Sir, could you please make a video on efficiency calculation in DC DC buck converter as function of load current.
Perhaps this will help th-cam.com/video/HtwiIIPekfs/w-d-xo.html
Why do we use a coupling capacitor along with a transformer in the "current driven rectifier" of a resonant LLC converter ?? Could you pls share some thoughts. Thank you
Can you send a sketch of the circuit you are referring to> There are a number of configurations to the current driven rectifier
@@sambenyaakov could you please share your email id. Thank you.
@@Rajat0607 sby@bgu.ac.il
Sir at 18:06 , how Q3 body diode conducts even if voltage on the line and drain of Q3 are at same potential ?
I understood because of lagging nature of circuit the current is starting slow and switching losses are reduced
You mean "line and drain" or "Line and source"? What does it matter if line and drain potential is the same?
@@sambenyaakov Sir , I meant how body diode was conducting from the point other than line(Vin) of MOSFET Q3 to line(Vin) ; Is it because of Capacitance of 1st and 4th MOSFETS
I have a general question sir, How can I view resonant current waveform on oscilloscope in h-bridge resonant converter .
Use a current probe, or voltage across resonant capacitor.
A correction, you only see Odd Harmonics for a certain duty cycle.
Thanks for comment. To which minute are you referring?
@@sambenyaakov Sorry! I guess you point out 'Square Wave', I just thought of a general duty wave.
Thank you for your efforts,pleasei was wondering if you could explain LLC converters and how do they works,i need that in my thesis.thank you
Go to TH-cam and search for "sam ben-yaakov LLC"
@@sambenyaakov please sir,i was wondering if you can tell me how we can achieve ZVS in LLC converter with GaN half bridge topology and GaN don't have a body diode,so where does current flow to make voltage across the device zero before turn it on.thank you
@@frajbenarab5523 There is reverse conduction but with a high voltage drop. So the only way is to minimize the deadtime.
@@sambenyaakovBut sir if we minimize the dead time ZVS transition will not take place and we are in case if hard switching and losses will increase,i'm designing an LLC with high efficiency above 98%,that is why i should focus on losses.
@@frajbenarab5523 Dead time has nothing to do with ZVS if you keep the deadtime somewhat longer that it takes the mid point to commutate.
Dear Sir Sam! i have read other articles and conducted experiments,and i doubt that transistors can have soft swithcing during turn off as you stated in your video. yes,they are turned on softly,but not turned off. can you give me some evidences that iam wrong?
Thanks for comment. Firstly, lets clarify a possible misunderstanding: 'turn off' refers to the current of the transistor (Vds is rising). 'Turn off' snubbers, resonant converters, phase shift PWM and others are widely used in the industry to achieve pseudo ZVS (slowing down dv/dt of Vds). There are literary hundreds if not thousands of papers and application notes on that .
Hello Sir, can you make a video on current fed dual active bridge converters. Thanking in anticipation.
I will put it on my todo list (-:
@@sambenyaakov is there a slight chance it will be up anytime soon ?
Indeed this is an interesting, important and relevant topic. Will try.
since we have single stage dc dc conversion why we are going to resonant dc dc conversion,suggest any books and applications on it????????????
I do not follow you. Compare/ the LLC converter with hard switched PWM
I mean we have buck, boost and buck boost with soft switcings then again we are using resonant converters in some applications, why ???? that's my question sir.
Nobody suggested that resonant converters replace all hard switched converters. In some cases they are superior. So what is the question?
@@sambenyaakov so What are that cases ? and In which applications resonant converters are used right now?
@@gurusumanth480 ieeexplore.ieee.org/search/searchresult.jsp?newsearch=true&queryText=resonant%20converters
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