My ZVS driver setup and how does it work
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- Опубликовано: 13 окт 2024
- In this video I explain the operation of a very popular inverter circuit commonly known as Mazilli ZVS Driver and tell about my experience with it.
I know this video turned out to be pretty long, so here are the time codes of the main parts:
00:27 explanation of circuit operation
3:38 calculation of the peak primary voltage
9:28 secondary components of the circuit
11:53 my setup and the features that I've added
18:40 waveforms of the circuit in operation
22:25 high voltage arcs
Edits:
Stp24nf10 has 55 mOhm Rds(on), not 5.5 mOhms as stated in the video.
Great explanation of the theory. Love that you got into the math!
Thank you!
This was the best video I've seen yet about ZVS anywhere on the web! Thank you! I would also like to know more about how to make sure why they are called ZVS or ZCS. I saw somewhere that the circuit can be adjusted so that the Xc and Xi don't cross over when the mosfet turns on, so that there isn't much wattage when the fet switches, but I don't really understand it yet. Anyway, I really appreciate it.
Thank you so much! ZVS is plainly simple, really: imagine a closed MOSFET acting as a switch with a voltage V applied across it; when it opens the voltage across it drops to almost zero and the current goes up. So there is a moment somewhere in the middle when both voltage and current through the mosfet are at an intermediate level, so the power P=V*I is dissipated on the mosfet as heat. That is the loss that occurs in every switching cycle. Now imagine if the voltage across the mosfet was zero to begin with. So when the mosfet opens the voltage stays at zero level and no power is wasted. Voilà, ZVS achieved. ZCS is the same but with current being zero to begin with. Basically the same thing, it's just that in reality in different applications when you have just a little bit of voltage or current left, not perfect zero, sometimes it does matter which one it is.
Thanks for this! I spent a while looking for the best explanation of output peak, and found nothing. This is exactly what I needed.
THE best video I've seen about the ZVS circuit. Wish I had seen it sooner. The way I managed to mostly understand it, is by endlessly messing around with it in a circuit simulator.
There is still one thing that confuses me a bit, and that is the current in the split primary winding. Current always flows into the center tap (due to the series inductor), and then through one half of the winding to the conducting mosfet, while at the same time the resonant capacitor passes current through the entire winding. I understand that these 2 waveforms overlay each other, but it's just a bit hard to visualize for me at every moment of the circuit operation.
There also seem to be quite a few unusual states the circuit can get into. For example I once got a situation where instead of oscillating at 36kHz or so, my circuit was "working" at around 2kHz. I later figured out that this was likely the circuit continuously trying to start, but failing to oscillate. The voltage was overshooting way beyond normal. Surprisingly, nothing broke. This seems to occur sometimes if there is too much load at the output.
Also, every time the load changes, there can be pretty big overshoots as well.
Haha, yeah, it tends to do that! You see, when you load the transformer, the apparent inductance of the primary decreases. At full loading it becomes equal to the transformer's leakage inductance, which is extremely small. This might give a hard time to the ZVS when it tries to start. And that's why with loading (arcs, voltage multipliers) the operating frequency jumps up.
This video is great, and so is the channel! I came here from styropyro, and I must say that it's been a long time since I found a channel this good.
Thank you very much!
Hi!
I know this video turned out to be pretty long, so here are the time codes of the main parts if you need them:
00:27 explanation of circuit operation
3:38 calculation of the peak primary voltage
9:28 secondary components of the circuit
11:53 my setup and the features that I've added
18:40 waveforms of the circuit in operation
22:25 high voltage arcs
Enjoy!
What about this layout lacking the center tap i.stack.imgur.com/tpu6c.png Can you do a comparison video ?
Can you film your version of this /watch?v=X5sCM2q6PXU using your ZVS ?
styropyro copied from you watch?v=MezaRnLSGhM&t=5m26s
I love this explaination about the Mazilli ZVS driver, by far the best I've seen on RUclips so far about this circuit, thanks!
How in the world did it take me so long to find this video and showing the math?! Thanks bro, this helped me so much and now I can get back to my ZVS project from 4 years ago!
I'm glad to hear that!
Thank you for the circuit schematics. I'm currently rebuilding a power supply for a nd-yag laser. This will help me a lot.
Thank you for such an in depth video!
You're welcome!
Very informative!! 👍
Hopefully the one person who disliked will never touch high voltage, because this is absolutely the best explanation anyone's ever gonna get!! 👍
Thank you so much! I've put a lot of work into this video.
P.S. sorry, I just have to make this joke: Impressive. Let's see Paul Allen's ZVS.
@@Vidduley I have never made a single RUclips video in my entire life. 😂 I've done a lot with electronics, but I've also never made a flyback driver, & I need one for my chemistry projects. I found your video (among many others) while learning, but yours is definitely the best at explaining how & why it works.
I'll have it built soon, but it probably still won't be on YT. 😂🤣
@@fieroboom haha he was making a reference to the movie "American Psycho" where there's a famous scene where the protagonist says "Let's see Paul Allen's card"
Ох уж этот знакомый акцент и звук вк 😏😏🤣а видео класс! Все подробно обьяснил☺️
Спасибо :)
What determines the frequency of the ZVS driver? Is it L1C1? You also mentioned in another video that you are heading back to Uni. I am curious, what is your main field of study?
Wow, impressive attention to my videos, thank you so much! The no-load frequency is determined by the complete resonant circuit: (L1+L3) and C1 with the usual formula. When there is a load on the secondary, mutual inductance comes into play. My major in the university is electrophysics and pulsed power.
Great explanations. Obviously, the oscillation frequency is fixed by the choice of hardware components. What would you think about alternatively just using a simple single MOSFET setup (no feedback coil) and connecting an Arduino to the gate pin in order to control the oscillation pattern by software? This would mean less components that can fail, heat up etc. Do you see any problems with such a setup?
Well that's basically a flyback converter, isn't it? Yes, that is widely used, however inductive kickback from the windings and hardswitch regime (hence high switching losses) limit the power of such ciruits to 100 W, and the transistor heats up. Here we operate in ZVS regime, so the switching losses are low and the output power can be quite substantial, people draw kilowatts from such ZVS setups.
i Have seen tons of videos. Thanks for including real cience showing values with Calculus.
Excellent presentation, clear and concise, many thanks.
Nice work tavarichch. I see you can also do math calculation and apply it to the real world. Bravo.
thanks for the explanation. good stuff. glad you included the fourier series calcs too.
I'm glad you like it, thanks!
This is a *baller* video!
Thanks for this in-depth description, you really helped me understand! That is so bad ass!
Thank you so much! That is my very goal, to make people see exactly what's going on from a physics point of view :)
Nice discussion! What I see is that the L5 coil both charges and discharges through the L1 and L3 work coils. Or the L5 coil is pulsing energy into the C1 work coil resonant tank. More importantly the counterEMF of the L5 coil is providing its counterEMF (collapsing reactive energy) to the work coils before going back to the DC source.
Could you do me a favor and measure the VARS and Watts supplied to this circuit unloaded and then loaded with different sparks? My guess is that VARS would dominate?
i think i have to rebuild my zvs driver because i keep blowing the mosfets after running for a few minutes when i feed 48v into the circuit. I think the zener diodes can't push the voltage down enough for the gates or they are not fast enough. But i haven't been able to push my self wound flyback transformer to the limit yet. it uses a 3d printed winding body with seperated sections and the center piece of a broken ferrite from a flyback transformer. it fits perfectly inside a mason jar so i isolated everything with dried Rapeseed oil pulled a vacuum and released it again to get the air out between the windings. I planned to release the stl files on thingiverse but i haven't done it yet
Sounds great, maybe you should try 200+ volt mosfets or better heatsinks. Also maybe the number of primary turns you're using is too low, that could draw an excess amount of current.
How would you use a digital signal to turn the ZVS on and off when the load is a capacitor and it has charged to the desired voltage or falls below the desired voltage??
Perhaps:
(1) Use a comparator (with hysteresis) and power transistor to cut on/off the supply voltage?
OR
(2) Pull both mosfet gates LOW with an open-drain transistor controlled by the comparater?
What do you think??
Thanks much...
Thanks for making a more indepth video!
You're welcome!
Great thing! One thing maybe should have been better explain. LC circuit is not charged. C is charged, due to inrush of happy electrons available at the IGBT (since it is open) then discharged through L (oscillation starts). Other side of capacitor is getting more positive at the same point (imagine the curve, too). When you think in real electron flow, it is much easier to understand what happens. In short, once opened, IGBT is a source of the electrons, and PLUS is eager to get those. After that, it is easy to imagine why do we need chokes too, and how their values must be precisely calculated (to find the sweet spot, to both, preserve the efficiency and calm the inrush of current) . Another thing - at 5:25 you said that inductor is not making any resistance to direct current. It does, at the beginning (hence use chokes, too - same goes with capacitor (in the opposite way), they are "passing" DC current at the beginning, until they are charged.). Also, that is not DC, it is alternating current "above" ground (it changes is value). Thanks for sharing!
Thanks for such a detailed comment! I'm not sure what you call IGBT, the transistors here are MOSFETs; your point of view seems entirely valid, it's just that in the video I look at the steady state of the circuit, and you look at the start-up transients; the latter of course can't be thought of in terms of DC/AC resistance and should be analysed with basic v=L*di/dt and i=C*du/dt principles - just what you said about electron flow, written in a math language.
ONE REASON I AM INTERESTED IN COMMUNICATING WITH SUCH AN EXPERT...
I have need a " VERY fast capacitor charger" and plan to use a ZVS driver running from 12v to 24v...here's the thing: I need a ZVS type output, but at about 600v to 800v. A regular ZVS driver's Vo is to small, and I certainly don't need the 10's of kV from an attached flyback xfmr. I'm thinking of using a ZVS driver fed into an HF transformer with a FWB output made from four SiC diodes. I even ordered an ebay HF transformer, but doubt I'll be lucky enough for a match.
Дякую за гарне пояснення.
Всегда пожалуйста!
I have the ZVS open board coil heating unit model with bright top copper heatsink + top fan for 12v use. I need 200watts output to ONLY run a 30v AC transformer. 3 terminals on output. . The advertising says only 100watts. Can I reduce the choke coil L inductance for higher current going to the center tap of transformer ? Or should it be only larger capacitance than on the board that resonates with primary of transformer? ( 200W Inverter power supply needed.) This is called self excited type rather than the IC Oscillator driven type. The MOSFET switchers on board are fully capable. Low voltage output + high wattage Inverters are non purchasable and transformer has to be hand wound special. (already done with bifilar primary...) ///?
"... fireworks in the background, you know it's New Years..." :D:D:D typical engineer - spending NY's eve working on awesome circuits :D
Great video!
Very nice thank you. First class explanation. Keep it up. Bless you
Thank you!
Very impressed with you mathematical understanding. Subbed! 👍🏻
Thank you :)
What oscilloscope do you use?
Isn't it possible that on occasion the mosfets will turn on simultaneously at startup causing a damaging short?? I would fear this when it's used often in a critical circuit that must be VERY reliable!! Can;t some sort of 'delay circuit' be used on one FET to insure this can't happen!?
THANKS FOR TE EXCELLENT VIDEO!!!!!
Hi, I think if you were to deliberately make one of the gate resistors say 20-50% higher in value than the other one, the circuit would still work with no problem, while such an arrangement would ensure the delay you're looking for
But using a fuse in series with the supply line is never a bad idea, just in case of a damaging short like the one you mentioned
@@Vidduley Perhaps, maybe splitting the values, as you mentioned, ie: one resistor X% less, and the other X% higher. Minimizing the deviation...just a first thought...
Great stuff, thank you Vidduley
My pleasure!
What’s the highest frequency you’ve tuned your ZVS to? Have you ever tuned it to the megahertz range?
No, the highest I tried was 90 kHz
Is it OK to run the ZVS driver with NO load on the output??????
Добрый день. Хорошее объяснение. Уточните пожалуйста : Если питать ZVS - драйвер от DC 12 Вольт, то амплитуда импульсов на выходе драйвера будет 12 Вольт х 3.14 = 37.68 Вольт ? И еще вопрос : почему Вы используете несимметричные умножители напряжения с симметричным ZVS - драйвером и будет ли разница если использовать симметричный умножитель ?
Спасибо! Амплитуда синуса на конденсаторе первичного контура будет 37.7 вольт, да. Я использую не умножители с драйвером, а драйвер с умножителями :) т.е. питаю умножители тем, что есть под рукой и выдержит наводки. Разница конечно будет между симметричным и несимметричным, спрашивайте конкретнее. У несимметричного плюс такой, что земля высокого потенциала и высокочастотного питания совпадают. У симметричного же, если я правильно понял, о какой вы схеме, оба конца высоковольтные относительно земли. У меня есть и такая конструкция)
@@Vidduley Благодарю. Схема, изображенная в видео "How to protect your high voltage multiplier... " будет ли работать с ZVS драйвером ? Хочу собрать 8 ступеней умножителя по приведенной схеме.
Будет. Она по сути с ним и работает :)
pretty good explanation, we have (i think) the same scope
Thanks! That's Hantek 4202C, but now I use Siglent SDS1202X-E, it's much better
@@Vidduley oh ok, i think i messed up, your hantek has a black frame but mine has not, it's a DSO5102P, pretty basic scope but it works for me
I was under the assumption that a high voltage supply like this would require a ballast to prevent drawing to much current while pulling arcs. Is it possible that increasing the primary turns of the transformer can limit the maximum current through the zvs?
You are correct, high voltage supplies often need ballasts, but this exact circuit is self-oscillating, so when the arc is pulled, the circuit will resonate with pretty much any ballast to push maximum current through it (except for a HV resistor). I believe ballasts are needed with 50 Hz x-ray transformers and such, where you have very fine wire secondary with 100k turns or more, because such secondary is much more susceptible to overcurrent meltdown. Flybacks, on the other hand, can usually handle arc currents fine. I measured current in a ZVS arc to be about 300 mA RMS. I'm not sure what is the exact mechanism by which it is limited to this value.
@@Vidduley Thank you very much for the response.
If you could help me to understand one more thing, I would appreciate it.
What determines the current draw from the DC input? I've noticed that if the secondary of a transformer is shorted there is almost no current draw to the DC input of the ZVS. When a small arc is made the DC current increases, but is still only a few amps. When an arc is drawn out multiple centimeters the current draw quickly increases on the DC input to over 10 amps.
Does a ZVS need some form of over current protection, or does it self limit as long as it's operated at the right voltage?
I was thinking about it some more, I'm guessing it has to do with increasing impedance in the primary coil. As more turns are added to the primary the inductance increases. This higher inductance causes increased impedance to the flow of current, limiting power output at high frequency.
I'm still a bit confused about the short circuit condition on the secondary though, as the frequency on the primary rises and the inductance drops, yet power consumption is greatly reduced.
You know, this short circuit thing puzzles me as well (I've noticed it too). I don't have a clear explanation ready, but intuitively it seems to me that this effect works like that: the ZVS runs a resonant current of constant magnitude through the LC circuit (determined as Vpeak/Z where Z is √(L/C) ). The transformer is just a part of this resonant circuit. After that if we include some resistance in this circuit, the current might not change much because of the resonance, but now it will dissipate some power equal to I^2*R. The bigger the R value, the higher the losses. So in short circuit when total R is small, the the power draw and dissipation is small. When we make an arc, it's resistance is quite high and it dissipates the energy effectively, hence larger power draw.
To sum it up, this effect can probably be explained by the fact that ZVS circuit creates an AC current of constant magnitude through its load. With 0 ohm load there will be 0 power dissipation and 0 power consumption. With higher value loads the power consumption and power dissipation go up.
oh brother I just bought a few stp75nf75 and I am building a zvs this helps me a lot , I will let you know if I got it to work
Good luck! I'm always glad when my videos help someone
@@Vidduley thanks I build it and it works great , I been doing some testing with induction heating and mostly using it with a transformer and a bridge rectifier to charge capacitors works flawless
Hallo Vidduley
For information: This schematic is the german patent - nr: 35 19 489 from 30.11.1989!
Hello, it really is, thank you a ton! That is a really interesting piece of historic info. Do you happen to have the link to the full patent with pictures? I was only able to find it on Google Patents in text form. Also, is that just a coincidence that your nickname and inventor's name are the same ? :)
@@Vidduley Yes, this is my patent, and no Mazilli!
@@Vidduley Sorry, i have no link.
Cool! Can you tell us more about this circuit's original intention? How did you come up with the idea? In what equipment was it used? How popular is it now in modern electronic devices? If you're not feeling comfortable answering that here in the comments, you can get back to me at vidduleymail@gmail.com .
@@Vidduley Sorry, bat my english is not good enough for do this.
I have seen a lot of schematics that omit L5, and just connect through a wire. What do you think?
As I understand it, L5 is basically an RF choke that decouples the LC tank from the DC supply, which allows the voltage on the tank to swing up to 3.14*Vin; otherwise this voltage would be clamped to the supply voltage. I think the circuit would still work without L5, it's surprisingly robust to things like that :) but for proper operation I believe L5 is needed
@@Vidduley Sounds like THE answer...THANKS!!
Love your channel man!
Thank you!
how to prevent both the mosfets from turning on at the same time?
When I power on the circuit, if high voltage electrodes are not near enough then circuit doesn't oscillate and both mosfets turn on and max current flows and overheats mosfets.
I mean how to make the circuit oscillate without the kickback from secondary?
This driver is better than Hbridge. Mosfets stay cool...
That seems impossible, because gate of each mosfet is shorted to the ground through the other mosfet's drain in open state. Only states with one mosfet turned on are able to physically exist in this circuit. Maybe some of your components are faulty and that causes this odd behaviour?
@@Vidduley Thanks for the reply! 😊
It turned out that, in above condition, mosfets were not turning on fully and were acting as resistors. This was forming voltage divider between 470ohm and (gate-drain diodes + mosfet drain-source resistance). So gates remained at high voltage.
Culprit was the 4Amp 12v Halogen bulb in series with primary, which I am using for limiting current.
I solved this by using two separate 18650 batteries(8.2V) to supply gate voltage. Now I can increase primary voltage without worrying about melting 12v zener dioes.
Also, I gave 1-2 turns on ferrite core and attached two LEDs antiparallel with 1k resistor for indication of oscillations.
Oh, very interesting, thanks for sharing!
Hello, how did you probe the mazzili driver output with the oscilloscope? The oscilloscope ground lead is directly connected to ground, and I would imagine it would just short the power supply if connected directly to the output, right?
Hi, yeah, it would short the PS, so I measured the output points (drains of both MOSFETs) in reference to the power supply ground with two channels of my oscilloscope and then used its math function to display the difference between these two points, which is precisely the output voltage of the ZVS.
@@Vidduley Alright thanks, that makes sense! :)
You know what, now when I think of it, maybe I did probe the output directly. My low voltage DC PS that powers the ZVS is isolated from the ground, so I could probe anything on the ZVS directly. Differential method is still safer though.
@@Vidduley Oh I see. Isn't that the case with all DC PSUs though?
There exist transformerless power supplies which aren't galvanically isolated from the mains.
Great explanation of the circuit! Thanks for doing the video man. 👍
My pleasure, thank you for watching!
Why do the gate resistors draw large current??
Because they are also current-limiting resistors for TVS diodes and UF diodes
SORRY: I meant "air gap"
I disagree with you about Vpeak. Voltage induced at the coil is d(flux)/dt not thing to do with Vinput.
By the way, thumb up for trying.
Well, if we're feeding the circuit from a fixed voltage source, it forces the d(flux)/dt to be governed by Vinput, no? Those are two sides of the same equation, you just have to understand what is fixed and what is governed in any particular case
What is the purpose of the choke?
Its purpose is to prevent the AC oscillations from being shorted by the DC supply (the supply is seen by the AC signal as a low-impedance short). The choke value must provide an impedance somewhat greater at the operating frequency than the LC impedance of sqrt(L/C) Ohm. Incidentally, the choke also provides a steady-state condition for the LC circuit that is known as Current-Fed Mode. The current through the choke is steady (unchanging) when the DC supply voltage on one side of the choke equals mean voltage on the other side of the choke so there's no mean voltage difference across the choke. Because the voltage on the other side of the choke is sinusoidal half-wave, whose peak and mean values relate as the number Pi, the peak value in steady state becomes Pi times the DC suplly voltage. This explanation, I think, has a bit more physical meaning than the one I gave in the video using Fourier series. The reason I didn't give it back then was that I understood all of that long after I made the video😅
cool
J'aime votre chaîne et le dévouement que vous accordez à vos projets. Il ne s'agit pas de spam, mais connaissez-vous la chaîne glasslinger? Je vous recommande d'avoir des projets très intéressants!
Enfin, je m'abonne à votre chaîne et j'espère voir d'autres projets intéressants!
Les gens comme vous les motivent à apprendre de nouvelles choses!
Thank you so much for your kind words! I hope that Google Translate haven't lost much here, and you mean the channel glasslinger? Unfortunately I've never heard of it.
2 Forces Pushed JLQY Pulled jrQñ 2 mosfet can be on at the same time Paralel now zvs zeries returded...
1:20 Оу, вэй. Разве полевичок со встроенным каналом не открыт, когда на затворе-истоке нет напруги?
Конечно, но большинство мосфетов (как и эти) имеют индуцированный канал, так что они открываются только если приложить напряжение к затвору
@@Vidduley Окститесь!
Индуцированный канал - это канал который надо индуктировать, т.е. в отсутствие напруги на затворе-истоке полевик закрыт. От того и обозначение канала в таких транзисторах в виде прерывистой (разомкнутой) линии. Стрелка же в полевиках (в отличие от биполярников) всегда указывает на направление тока для размыкания канала.
Вы говорите о Jfet, а я о мосфет)
@@Vidduley Ладно, речь шла о стрелке в полевиках с изолированным затвором. В полевиках с управляющим p-n переходом (JFET) стрелка в ту же сторону, что и у биполярников.
Так на рашн вики пишут.
Hey, would you mind if I translate ur content to Spanish? I'd like to work with u
You have any social media?
Yes, you can follow me on instagram at @instavitas
Interesting that half the time you say mosfet is closed, but you mean open!
Yeah, that's true, sorry about that; Russian and English languages have the opposite namings for MOSFET states 😅 It gets a little confusing in the head
My ZVS, does not workin. ??? 🤔
Make a jacobs ladder.
Good idea! It needs a little more voltage though.
@@Vidduley ya. I tried ounce but had to use a candle to start plasma stream lol. Didn’t have proper caps for the job lol .I just built some hv ones will try soon. Again.
a jacob's ladder is pretty simple with a color TV flyback, you can also use a "gabriel" electrode to ease the starting, made in 5 minutes after testing my ZVS.... the "gabriel" electrode resistor is already inside the TV, it's across the live and cold sides of the PSU, it's usually like 10 megs 3 watts, i always collect those resistors
@@redoverdrivetheunstoppable4637 awesome I will ty.
Could you put subtitles in English ? Please I'm peruvian speak Spanish
24:00
Почему ты решил вещать на английском языке? Для охвата большей аудитории или для тренировки английского?
Для охвата большей аудитории :)