We are designing/building forward converters to different specifications for a design project at university right now - this lecture was very helpful! Thankyou.
This was very informative, thank you very much. I was looking at schematics and could not get the reset winding to work in my head before I heard your explanation.
Hello. Nice video! I have a question. In the part of the video where the voltage is klamped (10:00), why do you need to do this in the forward converter but you do not need to do it in the flyback converter?
Dear Professor Yaakov, I can understand the n3/n1 calculation at 12:51, but it doesn't match with "n3/n1" at 16:49. Could it be that the "Vin*n1/n3" of S2 at 15:43 should be written as "Vin*n3/n1"?
Yes there is an error pointed out 4 years ago😊 JeffH 4 years ago Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don? Sam Ben-Yaakov 4 years ago Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Hii prof, first of all great lecture thank you! secound i will be more then glad if u can take a minute and replay . in the time t = 13:27 you show two formula's for the relation between n1/n3 that as i can see contradic each other. on the left side : n1/n3 > Don/Doff on the right side: n1/n3> Doff/Don what am i missing? is there a chance of a mistake? as far as i can see : n1/n3> Don/Doff is the right answer. thank you very mutch
Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Thanks a lot for the detailed explanation sir. I was wondering if forward converters have any practical applications? It seems that at low power ranges, Flyback would dominate and at higher power it is better to go for push-pull or half bridge. I would love to know your thoughts on the same.
Thanks for comment: Sam Ben-Yaakov 9 months ago Yes there is an error pointed out 4 years ago😊 JeffH 4 years ago Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don? Sam Ben-Yaakov 4 years ago Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Thanks for comment Sam Ben-Yaakov 9 months ago Yes there is an error pointed out 4 years ago😊 JeffH 4 years ago Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don? Sam Ben-Yaakov 4 years ago Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Hello Professor! My question regards a magnetization inductance problem (7:04) is follow: In a few sources I saw that there is a gap recommended in the forward converter transformer. But after your video I am realizing that gap is not needed. Even more, a gap should make situation even worse (Larger gap -> lower magnetization inductance -> higher magnetization current). Are there any hidden reasons to make a gap in a forward converter transformer? What do you think?
Strictly speaking the forward transformer does not need a gap. However, I would imagine that in some cases a gap can be helpful. For example: if DC current is expected at the primary or secondary or if the resonant frequency between primary and associated caps is very low.
In flyback' energy is stored in core and them discharged into the secondary. In forawrd energy is not supposed to be stored in core, but some does due to magnetization so this has to be discharged by a third winding. or some other means.
Can a toroid be used for the core of an isolated switch-mode power supply? I never see a ferrite toroid used for the core of SMPS when they have isolation, and I always wondered why. All of the buck boost converters I see use a toroid, but they are not isolated.
Thank for bringing up a good question. Toroids are used in flyback but less often. They tend to have a higher leakage inductance which is increasing losses and spikes. They would be a good choice if one needs very high insulation between primary and secondary because you can put them apart. Using ZVS techniques will reduce the leakage losses.
Great lecture Sir, at 12:05 why can't the demagnetization be performed on the secondary side of the transformer? and why can we put the catching diode across the transformer primary? I mean why add the third winding to demagnetize the transformer?
@@sambenyaakov I see. I thought the point of the reset winding was to make the flux in the core go completely to zero..which dosnt occur in CCM, right? what am i missing?
Hi Sam sir,I am designing two swich forward convter.. regarding isolation feeback ,Ti recently released opto-emulator which better CTR and no aging effect.There is question came why can't we use feeback winding or bias winding in the primary of the transformer for output regulation without any opto_emulator to reduce component count and also need tight regulation .Is it good to go with feeback winding in forward converter ?There is no application note with feeback winding in forward converter.What could be the potential issues ..you have any suggestion or opinion on this sir?
in slide no 7 . when Vreset > Vin. then during off period of switch. the anode of diode has Vin and cathode has Vreset. then how will the diode the turn on. and how will the reset happen??
When the inductor current is interrupted, the voltage tend to swigs toward very high voltage and clamped by Vreset. See ruclips.net/video/HtwiIIPekfs/видео.html
great sir, i have to design 20v 10 A , 0.1% ripple 2 switch forward converter i am new to power electronics , can you tell what will be the output inductor and capacitor
Thanks Professor. I have a question: You said at 12:01 that the magnetization current finds its way through the reset path (n3 winding). Could that current find its way through the n2 winding aswell? Greetings from Colombia.
Professor, thank you for your answer. Now a question that could be a little bit out of context: following the same procedure shown at 8:45 but in a push-pull, when both transistors are off, why the voltage of the transistor is just Vin? should not it be 2Vin? Thank you for your help.
Regarding to the first schematic, if it is a voltage generator, than I(in) will increase in the transformator, so I think the Io will not be constant acc. to Faraday's law (will increase too). So the rectangular signal shape is not correct. Am I right?
Well, you seem to be good in persuasions. I was planning to prepare next a video on "multiphase, interleaving and ripple cancellation". You think active clamp has priority?
Well well well, no thank you for sharing, no intelligent comment, just wailing like a baby. About 43000 people watches this video and only you are complaining. Doesn't it tell you something? Did it ever occurred to you that many of the people watching this video have difficulty understanding English and a lower pace helps them? Or that I myself am not a native English speaker and it takes me time to choose the words? So you slowed down the video, big deal. This is far below fake news, this is idiotic news. Grow up.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Great Lecture professor....you became single point source for power electronics for me
You are the best, thanks for all these clean explanations
🙏😊
We are designing/building forward converters to different specifications for a design project at university right now - this lecture was very helpful! Thankyou.
Thanks for comment. I am happy for being of help. Good luck.
Thank you Professor Ben-Yaakov. I love this style and format. I am looking forward to your other lectures.
Thanks for comment.
If it is Power Electronics, it has to be understood by Prof. Sam Ben Yaakov. Lots of love from the students in India.
Thanks. Good luck with your studies😊
This was very informative, thank you very much. I was looking at schematics and could not get the reset winding to work in my head before I heard your explanation.
👍
Первое нормально объяснение работы прямого преобразователя и особенно того как происходит сброс индуктивности. Спасибо.
Thanks to you and to Google translate.
@@sambenyaakovI did not expect you to read this comment and wrote more for myself). Thank you for this channel!
Thanks for the video! I'm preparing a test for University and your explanation was very helpful. I'm going to watch the Flyback converter video
Thanks for comment.
me too, T^T
Best explanation ever, keep it up sir 🔥🔥🔥🔥🔥🔥❤️❤️❤️❤️❤️❤️
👍😊🙏
Thank you so much sir for clearing our concepts
🙏😊
Thanks professor.....keep uploading such videos
Very detailed explanation! Thank you!
😊
really nice lecture. I wish you were my teacher when I first learned PE
Thanks
wow! professor thanks for nice explanation. I really enjoy your lectures.
Thanks.
Hello. Nice video! I have a question. In the part of the video where the voltage is klamped (10:00), why do you need to do this in the forward converter but you do not need to do it in the flyback converter?
In Flyback the clamping is by the secondary, save the spike due to leakage inductor which you need to clamp.
Dear Professor Yaakov, I can understand the n3/n1 calculation at 12:51, but it doesn't match with "n3/n1" at 16:49. Could it be that the "Vin*n1/n3" of S2 at 15:43 should be written as "Vin*n3/n1"?
Yes there is an error pointed out 4 years ago😊
JeffH
4 years ago
Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don?
Sam Ben-Yaakov
4 years ago
Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Hii prof, first of all great lecture thank you!
secound i will be more then glad if u can take a minute and replay .
in the time t = 13:27 you show two formula's for the relation between n1/n3 that as i can see contradic each other.
on the left side : n1/n3 > Don/Doff
on the right side: n1/n3> Doff/Don
what am i missing? is there a chance of a mistake?
as far as i can see :
n1/n3> Don/Doff is the right answer.
thank you very mutch
Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don?
Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Thanks a lot for the detailed explanation sir. I was wondering if forward converters have any practical applications? It seems that at low power ranges, Flyback would dominate and at higher power it is better to go for push-pull or half bridge. I would love to know your thoughts on the same.
Hi, Forward converters were used in the range of few 100s W. These days, the LLC seems to take over.
@@sambenyaakov that answers my question. Thank you very much.
@@sambenyaakov also I presume two switch forward was used in the 100W design? Or was it some other topology?
Thanks for the video, it helped me a lot.
👍
Hi Prof, i think there is a slight mistake at 14 min. n1/n3 shold be less than Doff/Don ( not Don/Doff). Please correct me if i am wrong
Thanks for comment:
Sam Ben-Yaakov
9 months ago
Yes there is an error pointed out 4 years ago😊
JeffH
4 years ago
Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don?
Sam Ben-Yaakov
4 years ago
Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Thanks for comment
Sam Ben-Yaakov
9 months ago
Yes there is an error pointed out 4 years ago😊
JeffH
4 years ago
Hi Professor, @14:12 shouldnt n3/n1 be less Doff/Don?
Sam Ben-Yaakov
4 years ago
Hi Jeff, correct. Indeed, the expression is messed up. It should be as you pointed out. Thank you very much for pointing this out. You have a keen eye.
Hello Professor! My question regards a magnetization inductance problem (7:04) is follow: In a few sources I saw that there is a gap recommended in the forward converter transformer. But after your video I am realizing that gap is not needed. Even more, a gap should make situation even worse (Larger gap -> lower magnetization inductance -> higher magnetization current). Are there any hidden reasons to make a gap in a forward converter transformer? What do you think?
Strictly speaking the forward transformer does not need a gap. However, I would imagine that in some cases a gap can be helpful. For example: if DC current is expected at the primary or secondary or if the resonant frequency between primary and associated caps is very low.
@@sambenyaakov Thank you, Professor!
So why flyback converter does not need this third coil?
In flyback' energy is stored in core and them discharged into the secondary. In forawrd energy is not supposed to be stored in core, but some does due to magnetization so this has to be discharged by a third winding. or some other means.
Can a toroid be used for the core of an isolated switch-mode power supply? I never see a ferrite toroid used for the core of SMPS when they have isolation, and I always wondered why. All of the buck boost converters I see use a toroid, but they are not isolated.
Thank for bringing up a good question. Toroids are used in flyback but less often. They tend to have a higher leakage inductance which is increasing losses and spikes. They would be a good choice if one needs very high insulation between primary and secondary because you can put them apart. Using ZVS techniques will reduce the leakage losses.
Great lecture Sir,
at 12:05 why can't the demagnetization be performed on the secondary side of the transformer? and why can we put the catching diode across the transformer primary? I mean why add the third winding to demagnetize the transformer?
The third winding helps to recycle the magnetization energy ruclips.net/video/OD8mBSsJfJk/видео.html
@@sambenyaakov ok but why can't we just put a catching diode in a parallel with the primary side.
@@thezodiace7399 this will not the magnetization. Zero n
voltage on inductor constant current
Sir, why shouldn't we connect the first switch (S1) to the return of the supply? (At 1:00)
? I don't follow.
at 19:18 you show the currents I1 and I2 start from a large value , then rise linearly, why dont they start from zero?
In CCM, the inductor current does not drop to zero
@@sambenyaakov I see. I thought the point of the reset winding was to make the flux in the core go completely to zero..which dosnt occur in CCM, right? what am i missing?
The current is a reflection of secondary not the magnetization current.
Hi Sam sir,I am designing two swich forward convter.. regarding isolation feeback ,Ti recently released opto-emulator which better CTR and no aging effect.There is question came why can't we use feeback winding or bias winding in the primary of the transformer for output regulation without any opto_emulator to reduce component count and also need tight regulation .Is it good to go with feeback winding in forward converter ?There is no application note with feeback winding in forward converter.What could be the potential issues ..you have any suggestion or opinion on this sir?
Regulation will not be that good in a forward conv.
Hi Dr. in the @07:03, if the n turns of the transformer ratio is higher, can we have Vout > Vin so a boost converter ?
Yes, but this is not a "Boost converter"
in slide no 7 . when Vreset > Vin. then during off period of switch. the anode of diode has Vin and cathode has Vreset. then how will the diode the turn on. and how will the reset happen??
When the inductor current is interrupted, the voltage tend to swigs toward very high voltage and clamped by Vreset. See ruclips.net/video/HtwiIIPekfs/видео.html
great sir, i have to design 20v 10 A , 0.1% ripple 2 switch forward converter i am new to power electronics , can you tell what will be the output inductor and capacitor
Forward is basically an isolated buck. See ruclips.net/video/HtwiIIPekfs/видео.html
Thanks Professor. I have a question: You said at 12:01 that the magnetization current finds its way through the reset path (n3 winding). Could that current find its way through the n2 winding aswell? Greetings from Colombia.
No, because of the diode in n2 (the voltage at this instance is of opposite polarity)
Professor, thank you for your answer. Now a question that could be a little bit out of context: following the same procedure shown at 8:45 but in a push-pull, when both transistors are off, why the voltage of the transistor is just Vin? should not it be 2Vin?
Thank you for your help.
In push pull, the secondaries are shorted which is reflected to the primary.
very good content
Thanks
Thanks for video, can we use a forward transformer for a resistive load without output diode?
You can but it would not operate as a forward converter. Just a transformer
Very informative video, thanks
Thanks
Can you explain about active clamping techniques also?
See ruclips.net/video/ySC-SvoQa3U/видео.html
very useful thank you a lot
Thanks
Thanks for this
Thanks
Thank you for this video, can we remove the inductor in the output and put just diode and capacitor like flyback converter?
No. This will be like a short (a transformer between input and output)
@@sambenyaakov thank you professor
Thanks for this great lecture
🙂
@@sambenyaakov I could give a good sheet in my exam.
Greatings from Turkey :)
👍😊
why the input voltage is DC, but we can use transformer to step up or step down the voltage in this circuit?
You mean AC instead of DC at input? No
Respected professor which type of DC-DC Converter is suitable for connecting PV System to HVDC transmission system.
I would consider a series resonant converter.
Thank you! This is very helpful
Thanks
Regarding to the first schematic, if it is a voltage generator, than I(in) will increase in the transformator, so I think the Io will not be constant acc. to Faraday's law (will increase too). So the rectangular signal shape is not correct. Am I right?
This is considered to be an ideal transformer which by definition is assumed to have an infinite magnetization inductance.
Dear Professor, now I understand. Thank you!
Can you please make a video on Active Clamp forward converter
Will try
There is no videos available in youtube that explains the working of Active clamp forward converter.
Well, you seem to be good in persuasions. I was planning to prepare next a video on "multiphase, interleaving and ripple cancellation". You think active clamp has priority?
just found ruclips.net/video/UidZ2Dy_XxA/видео.html
good quote but its just their product promotion, the explanation that you have given is very eazy to pickup.
thank you greatly for sharing
Thanks
I was thinking transformer is ac device then how DC voltage can be use on high frequency transformer, how switching helps transformer to operate on dc
The switching act transfers the DC to AC, like chopping, such that the transformer sees an AC voltage
Thanks
👍🙏
I had to set the speed to x1.5. The pace of the video was brutally slow. 🥱🥱🥱🥱
Well well well, no thank you for sharing, no intelligent comment, just wailing like a baby. About 43000 people watches this video and only you are complaining. Doesn't it tell you something? Did it ever occurred to you that many of the people watching this video have difficulty understanding English and a lower pace helps them? Or that I myself am not a native English speaker and it takes me time to choose the words? So you slowed down the video, big deal. This is far below fake news, this is idiotic news.
Grow up.
@@bismark5809 Thanks
@@bismark5809 👍👍