Author Topic: ZVS Mazzilli Driver rectified  (Read 4733 times)

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Offline nix85

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Re: ZVS Mazzilli Driver rectified
« Reply #25 on: June 17, 2019, 09:00:57 am »

A LC circuit needs power to flow back and forth between the L and C in order to have it resonate. The diodes let power flow into the inductor but the inductor is not able to send the power back trough the diodes into the capacitor. If you see a way to send power back trough the bridge then please explain how.

And again you're wrong. I don't see how you don't see the obvious. Current flows just like it would without the rectifier. Now i'll draw it for you.



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Yes indeed ZVS induction heaters work really well at high frequency. But notice that the coils they use have small cross sections and only a few turns? This is to keep inductance low so it can resonate so high while maintaining a very large current at voltages that MOSFET transistors can handle. The small coil has much less energy storage capability so a lot less power is needed to build and destroy the field around it.

All you need to do is to drastically reduce the number of turns to get to a coil design similar to a induction heater and then it will operate at high frequency without involving the massive power levels.

I know resonant frequency formula and i clearly said i will have to lower the number of turns/inductance to increase the frequency which is expected to be ~1.44KHz with noted LC values.

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Magnetic fields store energy just like a capacitors stores energy with electrostatic fields. The inductance in Henries defines how much energy the inductor can hold at a given current (just like Farads define energy for a given voltage on a capacitor).

So just like you need to put energy into a capacitor to raise its voltage you need to put energy into an inductor to raise its current. Because the inductor you are talking about is clearly large and you want to put a lot of current trough it this means the coil will produce a large and strong magnetic field, this is why its inductance in Henries is large.

Again you're repeating what i already know and is really obvious.

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I don't want to start off a free energy discussion because of how such discussions usually end up.

Zero wish to discuss it, you are not ready for FE and that's ok. Some day you will realize how undescribably wrong you were.
 

Offline Berni

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Re: ZVS Mazzilli Driver rectified
« Reply #26 on: June 17, 2019, 09:43:55 am »
A LC circuit needs power to flow back and forth between the L and C in order to have it resonate. The diodes let power flow into the inductor but the inductor is not able to send the power back trough the diodes into the capacitor. If you see a way to send power back trough the bridge then please explain how.
And again you're wrong. I don't see how you don't see the obvious. Current flows just like it would without the rectifier. Now i'll draw it for you.


Yes, notice how the positive side of the capacitor always ends up on the top end of the inductor. This puts energy into the inductor.

In order for the inductor to give its energy back out the voltage across its terminals has to go negative. It will indeed do this on its own if the capacitor stops supplying voltage. You can imagine this as replacing the inductor with an imaginary battery where the positive terminal points down.

If you track the flow of current around you will find that the current splits up on the two diodes and continues flowing trough the other two diodes and gets around to the inductor again. This makes for about -1.4V across the inductor due to the diode voltage drops. So the inductor is giving off energy but all the energy its giving off is just turning to heat on the diodes rather than making its way to the capacitor.

If you don't believe me try simulating this circuit in SPICE or if you don't trust simulations then  try building and and see for your self that this can't resonate in any usable away.

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Yes indeed ZVS induction heaters work really well at high frequency. But notice that the coils they use have small cross sections and only a few turns? This is to keep inductance low so it can resonate so high while maintaining a very large current at voltages that MOSFET transistors can handle. The small coil has much less energy storage capability so a lot less power is needed to build and destroy the field around it.

All you need to do is to drastically reduce the number of turns to get to a coil design similar to a induction heater and then it will operate at high frequency without involving the massive power levels.
I know resonant frequency formula and i clearly said i will have to lower the number of turns/inductance to increase the frequency which is expected to be ~1.44KHz with noted LC values.

Yes but this reduces the strength of the magnetic field generated in the coil.

Im under the assumption that your goal is to generate a magnetic field in the coil of a given strength (8A into 600 turns requirement). So if you half the number of turns to 300 then a current of 16A is needed to produce the same strength of field. Halving it again to 150 brings the current to 32A etc... By the time you end up at 10 turns the current is that 480A from before.

The other way is instead of a 600 turn coil you make two 300 turn coils each carrying 8A. By the time you get to 10 turns per coil you need 60 of these 8A each stacked together to get the same field.

Either way the reduction in the number of turns just shifts the high voltage requirement into a high current requirement. The power requirement stays the same 350kW because you are generating a field of the same size and strength.

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I don't want to start off a free energy discussion because of how such discussions usually end up.
Zero wish to discuss it, you are not ready for FE and that's ok. Some day you will realize how undescribably wrong you were.

Not that i'm not ready for it, id love to build myself a free energy generator to power my stuff. But so far i have yet to see blueprints for a free energy device that people managed to reproducably build and make it work as claimed.

To top it off a lot of the content on the topic of free energy has inconsistencies in the theory of operation or badly set up experiments. Things like misinterpreting magnetic forces, ignoring negative/positive signs on numbers, showing a misunderstanding of phase in AC power, doing measurements in crude or incomplete ways etc. All of this did give me a bit of a negative bias overall to this type of content.
 

Offline nix85

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Re: ZVS Mazzilli Driver rectified
« Reply #27 on: June 17, 2019, 11:05:36 am »
Yes, notice how the positive side of the capacitor always ends up on the top end of the inductor. This puts energy into the inductor.

In order for the inductor to give its energy back out the voltage across its terminals has to go negative. It will indeed do this on its own if the capacitor stops supplying voltage. You can imagine this as replacing the inductor with an imaginary battery where the positive terminal points down.

If you track the flow of current around you will find that the current splits up on the two diodes and continues flowing trough the other two diodes and gets around to the inductor again. This makes for about -1.4V across the inductor due to the diode voltage drops. So the inductor is giving off energy but all the energy its giving off is just turning to heat on the diodes rather than making its way to the capacitor.

If you don't believe me try simulating this circuit in SPICE or if you don't trust simulations then  try building and and see for your self that this can't resonate in any usable away.

As cap discharges magnetic field builds up around the inductor until cap is fully discharged and all energy is now stored in the inductor.

Now inductor discharges in the same direction and as current reaches the rectifier, remember at this point cap is empty, it has no polarity, so current can take either way.

The question is does current "chose" one way over the other (which would make the oscillations continue whichever way it "chose") or it spreads toward both sides of the cap and oscillation cannot continue in this way.

Realistically, it probably spreads out and thus no oscillation.



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Yes but this reduces the strength of the magnetic field generated in the coil.

Im under the assumption that your goal is to generate a magnetic field in the coil of a given strength (8A into 600 turns requirement). So if you half the number of turns to 300 then a current of 16A is needed to produce the same strength of field. Halving it again to 150 brings the current to 32A etc... By the time you end up at 10 turns the current is that 480A from before.

The other way is instead of a 600 turn coil you make two 300 turn coils each carrying 8A. By the time you get to 10 turns per coil you need 60 of these 8A each stacked together to get the same field.

Either way the reduction in the number of turns just shifts the high voltage requirement into a high current requirement. The power requirement stays the same 350kW because you are generating a field of the same size and strength.

Again you say things that are well assumed, i know amp x turns x permeabilty / core area formula.

I'll be using a bifilar so that adds to field strength. Breaking the coil into multiple smaller coils is surely not a solution. I'll find a compromise between no. of turns and amps and frequency.

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Not that i'm not ready for it, id love to build myself a free energy generator to power my stuff. But so far i have yet to see blueprints for a free energy device that people managed to reproducably build and make it work as claimed.

To top it off a lot of the content on the topic of free energy has inconsistencies in the theory of operation or badly set up experiments. Things like misinterpreting magnetic forces, ignoring negative/positive signs on numbers, showing a misunderstanding of phase in AC power, doing measurements in crude or incomplete ways etc. All of this did give me a bit of a negative bias overall to this type of content.

If you were ready for it, you would have researched it deeply and already figured at least a few ways to do it. This 2555 page book is just a tiny tiny part. So the issues are not those you noted, altho they surely do happen in certain amount, issue is the mental blindness. Let me tell you there are countless principles varying from mechanical to solid state. One little example, what is called back EMF or Lenz law can be completely neutralized so that the unit disturbing the magnetic field does not "see" the load. Another simple example, you can make spiraling iron rotor and place a permanent magnet near it, like this.



This will make the rotor always "fall" until it's closest to the magnet. At the point it wants to "stick", coil around the PM is briefly pulsed to neutralize it and rotor continues spinning with big energy gain (remember magnetic field falls with cube of distance). I am giving you "secrets" which will mean little to you cause you "know" it can't be done, yet it has been done for 100+ years.
« Last Edit: June 17, 2019, 11:22:05 am by nix85 »
 

Offline Simon

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Re: ZVS Mazzilli Driver rectified
« Reply #28 on: June 17, 2019, 11:48:05 am »
If you are going to pedal over unity BS I suggest you just leave. If you have a serious question do feel free to ask.
 

Offline nix85

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Re: ZVS Mazzilli Driver rectified
« Reply #29 on: June 17, 2019, 11:52:49 am »
If you are going to pedal over unity BS I suggest you just leave. If you have a serious question do feel free to ask.

I suggest you to bow down to gods doing what you consider impossible.

 

Offline Simon

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Re: ZVS Mazzilli Driver rectified
« Reply #30 on: June 17, 2019, 11:56:00 am »
Show me the God that can ban you for 2 days to see if you can come to your senses and ban you permanently if you do not!

Sincerely God's deputy!
 

Offline ahbushnell

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Re: ZVS Mazzilli Driver rectified
« Reply #31 on: June 17, 2019, 02:59:21 pm »
Yes extra inductance connected to the LC tank circuit becomes part of it, but not when its on the other side of a full bridge rectifier. The diodes prevent the energy from freely flowing back into the LC tank.
How do you imagine "diodes prevent the energy from freely flowing back into the LC tank", diodes are part of the LC tank and energy is perfectly free to flow between L and C both ways (only for L it is always in the same direction).


A LC circuit needs power to flow back and forth between the L and C in order to have it resonate. The diodes let power flow into the inductor but the inductor is not able to send the power back trough the diodes into the capacitor.

If you see a way to send power back trough the bridge then please explain how.

Quote
You could skip the rectifier and connect it directly in parallel to the LC tank circuit. But this adds a lot of extra energy storage to the tank so its resonant frequency will drop below 10KHz. You can partly mitigate this by making the capacitor in the tank circuit very small in value in order to get the resonant frequency back up. But this also reduces the current in the tank circuit at a given voltage level. So to still get your 8A in such a LC circuit you need to drive it at a higher voltage, again needing the 40kV across your coil, so as a result you need the DC supply to your ZVS circuit to be about 20kV and it must have transistors rated for 40kV.

"You could skip the rectifier and connect it directly in parallel to the LC tank circuit" i'm not sure what you mean here. I assume you mean the coil but coil is part of LC tank.

In any case there is no need for extreme voltages and power you guys mention since we are talking LC tank, no reactance here. This is why the ZVS heaters are so popular these days, they can push hundreds of amps at up to 200KHz (there are examples on YT). Zero voltage switching and no reactance, pure ohmic resistance and cold FETs.

I just calculated, with 0.18H inductor and 68nF cap resonance would be at 1.44KHz which is quite low. I will probably lower the number of turns/inductance to raise it to some degree.

Yes indeed ZVS induction heaters work really well at high frequency. But notice that the coils they use have small cross sections and only a few turns? This is to keep inductance low so it can resonate so high while maintaining a very large current at voltages that MOSFET transistors can handle. The small coil has much less energy storage capability so a lot less power is needed to build and destroy the field around it.

All you need to do is to drastically reduce the number of turns to get to a coil design similar to a induction heater and then it will operate at high frequency without involving the massive power levels.


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There is no free lunch in physics. This is how much energy it takes to make such a strong magnetic field.
That is so wrong it's beyond belief. Truth is the exact opposite. I humbly suggest you to start learning about overunity devices, you are already 100+ years behind on actual developments. Here's a good book to start your research. It's only 2555 pages long, so loads of fun and enlightment ahead for you.
http://www.free-energy-info.com/PJKbook.pdf

Magnetic fields store energy just like a capacitors stores energy with electrostatic fields. The inductance in Henries defines how much energy the inductor can hold at a given current (just like Farads define energy for a given voltage on a capacitor). So just like you need to put energy into a capacitor to raise its voltage you need to put energy into an inductor to raise its current. Because the inductor you are talking about is clearly large and you want to put a lot of current trough it this means the coil will produce a large and strong magnetic field, this is why its inductance in Henries is large.

I don't want to start off a free energy discussion because of how such discussions usually end up.
And induction heaters don't have rectifiers. 
 


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