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Author Topic: Kapanadze Cousin - DALLY FREE ENERGY  (Read 11718228 times)

Dog-One

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12105 on: February 13, 2016, 11:25:39 AM »
The only issue is the need for creation of an isolated dc pwr supply (B2) for driving mosfet's gates. Personally i prefer an isolated dc voltage for tl494 driving.

Almost all my custom boards have DC/DC converter modules on them.  Such as these attached.  You can draw your circuit up just as though you have little batteries and place them wherever you need them.  Completely isolated, no mess, no fuss.


magpwr

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12106 on: February 13, 2016, 12:46:13 PM »
Well, for the push pull i think it is a good choice for substituting ir2110 with two tlp250.
Some comparison:

TLP250: http://web.itu.edu.tr/yildiri1/mylibrary/data/tlp250.pdf
Io=1,5A
Propagation delay time=0,15uS typical (0,5us max)
output rise/fall time=6us

IR2110: http://www.irf.com/product-info/datasheets/data/ir2110.pdf
Io=2A
Turn-on propagation delay=0.12us typical (0,15us max)
output rise/fall time= around 25ns

There is a big difference between rising and falling times of the output pulse, but up to 25KHz that we need it for is fine. And of course what ever it happens at mosfet's side, our driving circuitry is protected up to 2500V
rms (min.)

The only issue is the need for creation of an isolated dc pwr supply (B2) for driving mosfet's gates. Personally i prefer an isolated dc voltage for tl494 driving.
The link below provides details on how to implement this.

http://tahmidmc.blogspot.gr/2013/05/using-tlp250-for-isolated-mosfet-gate.html

hi Jeg,

If you want super efficiency and lowest switching lost in uJ go go for Cree Silicon carbide mosfet.It's only around 16 usd each at 1.2kv .The gate capacitance is mere 950pf.You can figure out which one in digikey.com

My experiment conducted few years ago related to isolated power supply using optically isolated mosfet driver 2Amps ended in failure all 7 pieces.Replacement after Replacement.

My advise stay clear of those shitty item.Good ones are Adum1200(dual) or Adum1100(Single) is powered via 5volts and output is connected to mosfet driver of your choice.
In the end you will still need a isolated power supply module eg:Delta or etc.

I do own nearly 20 of isolated power supply module.I aim for 24volts output <400mA for SIC Mosfet.

If you take a look at Akula the (-) ground is common from supply to output to hv.In other words there is no supply isolation at all.


If you are using 12volts battery instead of variable power supply please do consider using self resettable circuit breaker eg:5Amp(12 or 24volts depending on voltage) rated as example.

Please do think about it.It's your call from here. :D :D



 

Jeg

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12107 on: February 13, 2016, 01:33:22 PM »
@D1
Nice idea! I have never mess with dc/dc conv. I took a look of DJ06S2412A which outputs 12V. It provides only 500mA at its output. Do you think is enough for fully opening and closing the gate at 17Khz?

@Mgpwr. Thanks for the advice. This cree mosfet looks interesting even expensive for experimental use.
Do you remember what went wrong and you blew all of your seven pieces?
self resettable circuit breakers. I use some fast glass breakers, but sometimes are not as fast as it needs to. I will searchfor what you are suggesting. Thanks

magpwr

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12108 on: February 13, 2016, 02:50:09 PM »
@D1
Nice idea! I have never mess with dc/dc conv. I took a look of DJ06S2412A which outputs 12V. It provides only 500mA at its output. Do you think is enough for fully opening and closing the gate at 17Khz?

@Mgpwr. Thanks for the advice. This cree mosfet looks interesting even expensive for experimental use.
Do you remember what went wrong and you blew all of your seven pieces?
self resettable circuit breakers. I use some fast glass breakers, but sometimes are not as fast as it needs to. I will searchfor what you are suggesting. Thanks

hi Jeg,

The parts mentioned can be found in digikey or mouser.Circuit breaker are more like medium to slow blow fuse.Only difference it is resettable.

The optical driver just fail merely driving mosfet with no HV or load connected.
It fail during burn in test for 1hr.

There some articles somewhere in internet which mentioned about these failures from opto mosfet driver.

The Adum1200 iCoupler is a good choice because it can do 10Mhz.But it depend on the suffix character.Just take a look at it's datasheet.

Think about the IX series mosfet driver can only do around 2Mhz max base on experiment which is good enough .

Dog-One

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12109 on: February 13, 2016, 03:05:22 PM »
@D1
Nice idea! I have never mess with dc/dc conv. I took a look of DJ06S2412A which outputs 12V. It provides only 500mA at its output. Do you think is enough for fully opening and closing the gate at 17Khz?

Easily.  Connect a smoothing/storage cap to the output--do not exceed the size listed in the spec sheet and you will be good to go.  Remember, the gate driver isn't delivering full amperage to the MOSFET gate for the whole cycle of the pulse.  It's a typical capacitor ramp-up curve; once it overcomes the initial charge disparity, voltage takes over and amperage drops off to nothing.

Now if you really want to overcome the ringing associated with a MOSFET connected to an inductor, you can use a bipolar arrangement of these DC2DC convertors to force the MOSFET off.  How?    Just put two in series, this is your drive swing.  Say you use two 12 volt modules, in series this is 24 volts delivered to the gate driver.  Now level set the MOSFET by attaching the Source in between to two DC2DC convertors.  Now you will have -12 volts on the Gate when the MOSFET is off and +12 volts on the Gate when the MOSFET is on.  Why would you want to do this...?

When you drive an inductor, what happens when you turn off the switch?  Recall an inductor fights a change in current.  It fights by way of creating a massive voltage potential.  And where does this potential go?   You have one side of the inductor fixed to the positive rail and the other side is essentially floating since you turned the MOSFET off.  So lets say the inductor and MOSFET Drain now shows a potential voltage of negative 40 volts.  Say what?  Yeah, that's inductive kick, CEMF, Lenz Law, whatever name you want to apply to it.  Look at where the Source of the MOSFET is connected--ground.  That should be zero volts rights?  And the positive rail should be say 24 volts right?  From the perspective of the inductor though, ground is now been pushed to minus 16 volts.  For a brief moment, what do suppose the voltage is at the Gate?  That's right, positive 16 volts referenced to the inductor.  Sixteen volts for a nanosecond is just enough for the MOSFET to begin to trigger again, even though the MOSFET driver tells it to be off.  The issue here is charge and its propagation speed.  It can get to the ground rail faster than it can get through the gate driver and back to the MOSFET Gate, so the MOSFET begins to switch back on.  You'll see this ringing on the scope when the MOSFET turns off with normal/simple drive circuits.

So pulling the Gate negative reference to Source is one way to help with ringing; the other way is to ensure you don't turn off the current to the inductor so fast that it kicks back.  Do both and you will have a nicely optimized drive circuit.  Attached is another "snubber" circuit that helps with kickback.  You will notice those resistors are 10 watts dissipation and they do heat up.  You can probe around with the scope all day trying to figure out why.   ;)


Jeg

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12110 on: February 14, 2016, 08:50:44 AM »
Easily.  Connect a smoothing/storage cap to the output--do not exceed the size listed in the spec sheet and you will be good to go.  Remember, the gate driver isn't delivering full amperage to the MOSFET gate for the whole cycle of the pulse.  It's a typical capacitor ramp-up curve; once it overcomes the initial charge disparity, voltage takes over and amperage drops off to nothing.

You are very right! I was always wondering how a simple lm7812 can provide 9A at gate side through a mosfet driver, the moment that 7812 itself can not give more than 1A.


Now if you really want to overcome the ringing associated with a MOSFET connected to an inductor, you can use a bipolar arrangement of these DC2DC convertors to force the MOSFET off.  How?    Just put two in series, this is your drive swing.  Say you use two 12 volt modules, in series this is 24 volts delivered to the gate driver.  Now level set the MOSFET by attaching the Source in between to two DC2DC convertors.  Now you will have -12 volts on the Gate when the MOSFET is off and +12 volts on the Gate when the MOSFET is on.  Why would you want to do this...?

Is that possible to make a drawing for this connection? I try to visualize it but i can't.

When you drive an inductor, what happens when you turn off the switch?  Recall an inductor fights a change in current.  It fights by way of creating a massive voltage potential.  And where does this potential go?   You have one side of the inductor fixed to the positive rail and the other side is essentially floating since you turned the MOSFET off.  So lets say the inductor and MOSFET Drain now shows a potential voltage of negative 40 volts.  Say what?  Yeah, that's inductive kick, CEMF, Lenz Law, whatever name you want to apply to it.  Look at where the Source of the MOSFET is connected--ground.  That should be zero volts rights?  And the positive rail should be say 24 volts right?  From the perspective of the inductor though, ground is now been pushed to minus 16 volts.  For a brief moment, what do suppose the voltage is at the Gate?  That's right, positive 16 volts referenced to the inductor.  Sixteen volts for a nanosecond is just enough for the MOSFET to begin to trigger again, even though the MOSFET driver tells it to be off.  The issue here is charge and its propagation speed.  It can get to the ground rail faster than it can get through the gate driver and back to the MOSFET Gate, so the MOSFET begins to switch back on.  You'll see this ringing on the scope when the MOSFET turns off with normal/simple drive circuits.

Also a very detailed explanation. I hadn't think that the capacitance between drain and gate can affect gate (which is normal), and so a negative value at drain side can present a positive spike to the gate!! I was looking at my gate oscillation trying to minimize it with a use of a parallel diode, but i hadn't ever wondered about why it oscillates.

So pulling the Gate negative reference to Source is one way to help with ringing; the other way is to ensure you don't turn off the current to the inductor so fast that it kicks back.  Do both and you will have a nicely optimized drive circuit.  Attached is another "snubber" circuit that helps with kickback.  You will notice those resistors are 10 watts dissipation and they do heat up.  You can probe around with the scope all day trying to figure out why.   ;)

D1, thanks man! I will start to use this kind of snubber in my circuits. Indeed the heat across resistance is very high as recently i tried it. But i thought it was a design error, and i omit it. 

Jeg

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12111 on: February 14, 2016, 09:28:49 AM »

The parts mentioned can be found in digikey or mouser.Circuit breaker are more like medium to slow blow fuse.Only difference it is resettable.



The last year and during ruslan experiments i have burn about 70-100 fuses on my mosfet board. I'll search for this resetable fuse. It might be a helpful addition for the job of exploring Ruslan's head! ;D

itsu

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12112 on: February 14, 2016, 11:13:23 AM »
Dog-One,  Jeg,

that is basically the same snubber setup as in Olegs green box setup, he has only 1 resistor while you have 2, see blow up below (ignore the red circle).
I tried it but it did not work for me, i still had massive ringing (1.4MHz) when the MOSFETs shuts off.

It would be good to see if Jeg has better results.


Presently i am changing the snubber setup to use a RC configuration as calculated by this website (using my 1.4MHz ringing):
https://www.maximintegrated.com/en/app-notes/index.mvp/id/3835


Regards Itsu

itsu

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12113 on: February 14, 2016, 12:12:42 PM »
I reworked my Yoke driver board (push pull) to give an as clean signal as possible to the yoke for any future PLL usage.

I used this website to calculate the snubber values of the RC components:
https://www.maximintegrated.com/en/app-notes/index.mvp/id/3835
I must say that it worked very well.

The present used components can be seen in the below diagram.
(i have disconnected the VD6/7 diodes (see my earlier post) from Oleg green box snubber setup so these components are not in below diagram)

The 1st screenshot shows the MOSFETs gate and drain signals when NOT in resonance.
Yellow drain MOSFET 1 
Blue gate MOSFET 1
Purple drain MOSFET 2
Green gate MOSFET 2

I am puzzeled about the drain starting signal which starts high, then falls of to the normal 48V. What is causing that?
Also puzzeled about the gate signals which seems to "lag" its drain signal, how can that be?

The second screenshot is across the 40W/220V bulb which is attached to the grenade.


Video here:  https://www.youtube.com/watch?v=5-vilYPhNn4&feature=youtu.be

Regards Itsu
« Last Edit: February 14, 2016, 11:06:11 PM by itsu »

magpwr

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12114 on: February 14, 2016, 12:31:19 PM »
I reworked my Yoke driver board (push pull) to give an as clean signal as possible to the yoke for any future PLL usage.

I used this website to calculate the snubber values of the RC components:
https://www.maximintegrated.com/en/app-notes/index.mvp/id/3835
I must say that it worked very well.

The present used components can be seen in the below diagram.
(i have disconnected the VD6/7 diodes (see my earlier post) from Oleg green box snubber setup so these components are not in below diagram)

The 1st screenshot shows the MOSFETs gate and drain signals when NOT in resonance.
Yellow drain MOSFET 1 
Blue gate MOSFET 1
Purple drain MOSFET 2
Green gate MOSFET 2

I am puzzeled about the drain starting signal which starts high, then falls of to the normal 48V. What is causing that?
Also puzzeled about the gate signals which seems to "lag" its drain signal, how can that be?

The second screenshot is across the 40W/220V bulb which is attached to the grenade.


Video here:  https://www.youtube.com/watch?v=5-vilYPhNn4&feature=youtu.be

Regards Itsu

hi itsu,

The bi-directional TVS diode 54Volts is not applicable for mosfet rated 200volts.The protection resistor for the gate can be increased to 10kohms.Although no issue using 2.2k at 18volts (8mA ea)

Sorry i have just seen the video.At 5+Amps at 24volts 120watt for lighting 40watt bulb.40/120 =33% efficiency.

That's the thing about using lower voltage mosfet.Alot of thing to factor in.

I do recommend using IGBT 1.2kv 25Amps rated  FGA25N120ANTD.

My 220volts 2000watt induction heater was using mere FGA11N120ANTD.11Amps rated.Reason being at higher voltage(mains) lower current is needed.


Please remove TVS Diode 54volts and implement a 200volts varistor.It's killing your efficiency.

My prototype snubber circuit(Not found in internet) which was not implemented for my PWM generator shown in video merely consist of 2.2nf 2kv caps and varistor value choosen base on around 1/2 the Vpp of the Bemf spike in series.It's implemented in my variable dc voltage generator up to 1600volts using 12volts as supply.

itsu

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12115 on: February 14, 2016, 12:56:16 PM »

Magpwr,

thanks for your comments, but could you elaborate somewhat on  "The bi-directional TVS diode 54Volts is not applicable for mosfet rated 200volts"?

Obviously a 54V TVS would not work when switching the max. 200V, but as we only should switch 48V with this 200V rated MOSFET, is it still "not applicable"?

The both TVS stay cool so i guess they are happy.

regards Itsu

magpwr

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12116 on: February 14, 2016, 01:08:33 PM »
Magpwr,

thanks for your comments, but could you elaborate somewhat on  "The bi-directional TVS diode 54Volts is not applicable for mosfet rated 200volts"?

Obviously a 54V TVS would not work when switching the max. 200V, but as we only should switch 48V with this 200V rated MOSFET, is it still "not applicable"?

The both TVS stay cool so i guess they are happy.

regards Itsu

hi itsu,

What i was trying to say the 54volts is underrated for your 200volts mosfet.
Why not create a one PWM circuit that works all the way to mains voltage around 300volts.

The best way to know just disconnect the output to kapanadze winding and note the bare Amps reading should be below 1Amp better still below 0.3Amps with yoke or toroid in itself.

I can't comment on your snubber because i am just sticking with Akula snubber which work at high voltage.Akula snubber circuit tallied by visual snapshot uploaded by someone in the past.

I just hope you don't get stuck at PWM.
-----------------------------------------------
I am currently working on Oleg nanosecond generator(Position control) which is combined with a  75hc132 1Mhz+ duty cycle control  via a sk diode.Something similar interrupter circuit of Sergey.

Doing last few test/adjustment at 23volts before going high voltage around 150volts to 280volts using 1.2kv mosfet once more for my high 'Q' Tesla transponder coil with Water pipe as Earth.

Variable capacitor 20pf to 1nf 1kv rated is used to find out the what  capacitor value to use to derive a suitable waveform display.


itsu

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12117 on: February 14, 2016, 01:31:46 PM »

Magpwr,

please forget about the efficiency for now, the bulb was just an indicator for resonance.

It does not matter what MOSFET/IGBT i use, they are not the cause of the amp draw, they are staying cool (19°C), but instead the
inductor coil / Wima caps series LC in resonance is causing the amp draw as there is about 750V @ 50 amps sloshing around there.

I could use 60V MOSFETs here as we only are on 24V (causing 48V to be switched) but the IRFP260's is what i had installed already.
With 60V MOSFETs the 54V TVS would be "applicable" then?

As i want to stay as close to the original plans as possible, i would not want to use a "PWM circuit that works all the way to mains voltage around 300volts"
Not sure what you mean by "kapanadze winding".


Thanks Itsu

magpwr

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12118 on: February 14, 2016, 01:50:59 PM »
Magpwr,

please forget about the efficiency for now, the bulb was just an indicator for resonance.

It does not matter what MOSFET/IGBT i use, they are not the cause of the amp draw, they are staying cool (19°C), but instead the
inductor coil / Wima caps series LC in resonance is causing the amp draw as there is about 750V @ 50 amps sloshing around there.

I could use 60V MOSFETs here as we only are on 24V (causing 48V to be switched) but the IRFP260's is what i had installed already.
With 60V MOSFETs the 54V TVS would be "applicable" then?

As i want to stay as close to the original plans as possible, i would not want to use a "PWM circuit that works all the way to mains voltage around 300volts"
Not sure what you mean by "kapanadze winding".


Thanks Itsu

hi itsu,

I meant do test yoke core in itself with nothing connect at it's output.

You should be getting <1Amps draw.If not you got to look for other alternative core or toroid or redesign circuit.

Time is running out i got to continue experiment then exercise then research to wrap up my day in the end. :) :) :)

itsu

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Re: Kapanadze Cousin - DALLY FREE ENERGY
« Reply #12119 on: February 14, 2016, 02:18:40 PM »

Quote
hi itsu,

I meant do test yoke core in itself with nothing connect at it's output.

You should be getting <1Amps draw.If not you got to look for other alternative core or toroid or redesign circuit.

Time is running out i got to continue experiment then exercise then research to wrap up my day in the end. :) :) :)


Ok,   it draws 500mA when nothing connected to either the 3 turn or 28 turn secondaries.

Happy experimenting with the Sergey nanopulser.

Itsu