вівторок, 14 листопада 2023 р.

Autotransformer - Generator


My investigation and common sense. If you are not able to think, analyze and draw conclusions do not read, do not get upset, take care of yourself read better fairy tales.  

In 2000, a note by G.I. Nikonov, a senior lecturer of the metallurgy department of a Russian university, "Autotransformer - Generator" was published in the press.


The readers' attention is offered a description of the device circuitry and supposed to start it from accumulators, an explanation of the device operation, which allows to power incandescent pamps from an autotransformer, introduced into self-sustained oscillatory mode by a special auto-oscillating circuit.
The prototype was the publications in the materials of the conferences "Aluminum of the Urals"
The interest was fueled by those students who attended the classes of the "Ether" circle in 1999-2000 at UGTU-UPI.

The original version was intended for easy ignition of a low-voltage arc and to keep it burning in the absence of special coatings of any metal electrodes. The arc was indeed easily ignited if the electrodes were included in the gap between the choke [Dr] and the transformer [Tr] (see Fig. 1). The circuit depicted in the figure worked on the students' day "Tatiana's Day", January 25.

A battery of alkaline accumulators was used as a source of power supply or start-up, connected in parallel to the regulated rectifier. Two batteries supplied the multivibrator on transistors T1 and T2. Electrolytic capacitors C1 and C2 of 50-100 µF were used. As C3 - a battery of electrolytic capacitors, switched on counter-sequentially. The best results were obtained when the battery of capacitors, divided into two parts, was connected by the middle point to the middle point of transformer TR1. Thyristors T1, T2 were used of KU203B type, because they allow to have a short switching-off time (about 10 µsec) and, besides, they can be connected three pieces in parallel, which can give an operating current of 50 Amperes. They allowed to obtain in the winding in the winding of Tr1 a sawtooth current, linearly changing, and voltage of rectangular form. This is the most important thing here

Then, when voltage is applied through capacitor C4, which has a capacitance of 5 µF (x650 volts), the autotransformer "Atr" type РН0-250-5 entered the auto-oscillating self-sustaining mode, which was achieved by moving both of its sliders connected with sliding roll contacts. The current initially consumed by "Atr" together with a 300 watt lamp Lamp1 connected to it was 2A. But after the excitation of the autotransformer was achieved, the current could be reduced to 0.1-0.2 Ampere (by raising up, up to failure, the upper slider of "Atr"). The fact that the lamp burns and the fact that the current drawn from Tr1 is significantly reduced, directly indicates that the ferromagnetic material of the core generates, although not very large, but significant electrical power. The frequency of linear current sawing is up to 400 Hz. The limitation is imposed due to the use of electrolytic capacitors. We warn those who would like to repeat the experiments that to reduce the probable destruction of capacitors due to outgassing, they should be used in the "C3" assembly at a voltage of 300-450 volts. After all, "electrolytic capacitors" do not always have the capacitance listed on their nameplate. They should be checked with an avometer (multimeter with capacitance measurement function).  The protection of such capacitors is also checked (in the first experiments) with water poured into a vessel. Cooling occurs, but it is a loss of energy. It is better to choose "electrolyte" capacitors of the same capacitance. The idea was that, having an autotransformer-generator system, run it from the batteries, then the energy gain should be used both to charge the battery (possibly the starting battery) and to power a third-party load. The energy gain is explained not only by the rotation of permanent magnetic moments "packed" in metal domains, but also by the rotation of additional spins of particles rapidly appearing and disappearing near iron nuclei. A candidate for this role could be a heavy unstable "electron" called a muon. It can quickly arise due to the processes of weak interaction from pions "stuck" to iron nuclei from the physical vacuum in the presence of "helium4" microparticles in the iron lattice. Probably, Cioffi managed somehow to purify iron from impurities and get a giant magnetic permeability exceeding one millionth of a fraction.  It is clear that such iron of a large degree of purification will not give an additional magnetic "echo" in the excitation winding. Therefore, iron ore - magnetite, having the formula Fe3O4, can also be used as a ferromagnetic material.

G.I. Nikonov, Senior Lecturer of the Department of Metal Science, UGTU-UPI Branch   


Let's omit the author's explanations about where the additional energy comes from, let's return to his scheme. According to the author's idea, the additional energy generated should be used to charge the starting battery and power the external load.  Let us sketch this position schematically: 

Looking at this combination, I immediately remembered a circuit for induction heating of metals (#1).  If instead of an inductor, a choke with adjustable output to the load, similar to a laboratory autotransformer [LATR] (#2), then we get just the scheme of Grigory Nikonov. 

In both combinations we have a series resonant LC circuit. It is hard to say how this increases the output power, but there is another very interesting inverter "LLC Resonant Converter" which also has a very similar conversion scheme:

The LLC converter is a resonant inverter with three reactive elements where the DC input voltage is turned into a square wave by a switch network arranged as either a half- or full-bridge to feed the resonant LLC tank that effectively filters out harmonics providing a sinusoidal like voltage and current waveform. This in turn feeds a transformer that provides voltage scaling and primary-secondary isolation. The converter power flow is controlled by modulating the square wave frequency with respect to the tank circuit's resonance.  In an LLC resonant converter, all semiconductor switches are soft-switching, or zero-voltage switching (ZVS), at turn-on for the primary MOSFETs and zero-current switching (ZCS) at both turn-on and turn-off for the rectifiers in the secondary; resulting in low electro-magnetic emissions levels (EMI). In addition, it can enable a high degree of integration in the magnetic parts, enabling the design of converters with higher efficiency and power density.

In this variant, in series with the series resonant circuit Lr, Cr, a transformer T1 and a choke Lm in parallel to the primary winding of the transformer are included in the selection system. In fact, the same combination as we have considered above, but there are significant differences. First, the primary winding of transformer T1 and the resonant inductance Lr do not have a common core, as in Nikonov's variant, using the resonant inductance and the selection circuit in the autotransformer mode. Second the reference oscillator has a variable switching system with a resonant chain (source plus and source minus) When switching to the source minus (galvanic part of the circuit) our whole chain is closed into a loop.  Whether this is important or not I cannot say, but you should probably pay attention to it.

Further exploration of possible implementations led me to Romanov's very interesting scheme [2012].


Romanov's video with this generator: https://www.youtube.com/watch?v=ZRfWTlbFy1k

Already in this circuit it can be seen that there is no ferromagnetic core in the resonant autotransformer L4 included in the main series resonant circuit L4, C3. Also added is a high-voltage resonant transformer based on Nikola Tesla C3, L2, spark gap, L3 (highlighted in green background). The resonant frequency of L2, L4 should be the same.   One more resonant circuit L1, C2 excited by the ZVS driver from the starting battery sets the oscillatory process and injects energy into the system. Romanov states that the filter consisting of C1, DR1 is selected for the required frequency.  In points A, B of the resonant inductance an element for power extraction is connected, putting the resonant inductance in the autogenerator mode.  Then, according to the concept, the harvested power is directed to charge the battery and through the inverter to connect the payload. Absolutely identical concept proposed by Nikonov [2000]. The addition is the Tesla resonant transformer and the manufacture of resonant coils L2, L3, L4 without ferromagnetic core. 


The topic is very interesting there is also a handyman "Electricworld" from Ukraine, who makes similar devices. I will not confirm or deny the operability of these devices, the only thing I will note is that with a possible actual increase in power, which can be taken from the resonant circuit to the load, this load must be constant. At change, disconnection and other delights on the calculated combination of power increase on load this effect will be immediately leveled. https://youtu.be/2sj7FHiXje8


There is another very interesting inventor of such technology - Donald Smith. I will not go into all of his variants, I was interested in only one of his devices, which overlaps with the ones we have discussed above. I took two schematics from his book "RESONANSE ENERGY METHODS", and compared them to the one we looked at above. 

What do you think made me suspicious in these two seemingly identical schemes? I've highlighted what confused me in yellow.What do you think made me suspicious in these two seemingly identical schemes? I've highlighted what confused me in yellow.  

In the two circuits of D. Smith, we formalize element 7 and 6a by analogy with the series resonant circuit and the autogenerator power take-off system, which we have considered above. After all, Smith has hidden something from us.

Figure # A shows the solution of power take-off through a resonant autotransformer with inductance Lr, Figure # B shows a variant of power take-off through a two-winding transformer. Both variants exist in practice with resonant converters. You will say that Smith's is different, to which I will reply that he has everything in blocks, which is well used to hide circuit features. I followed the logic and rules of practice for the power resonant circuit used in induction power circuits.    

The question arises whether it is possible to make this scheme simpler.  Let's return to Nikonov's original scheme. The DC/AC inverter signal generator is a multivibrator only on thyristors, in fact a ZVS driver, which is used to swing similar circuits. 

In this video [ https://youtu.be/yKjgMmZcFA0 ] the guy shows just this driver in the pumping mode of the resonant converter. The feature of the driver adjusts to the frequency if the inductance parameter of the resonant circuit is changed. This is the reason why it is often used in simple induction heaters, the second reason is simplicity. Also in the video, the guy demonstrates a traditional secondary circuit for a resonant converter in the traditional parallel resonant circuit mode. 

How this task is handled by appropriately qualified engineers. You will be surprised but we see the same solution, switching the energy transfer to the pickup circuit while maintaining resonance in the secondary circuit. 

But traditionally, as in all the variants discussed earlier, the resonant circuit is not used in the secondary circuit, in power take-off.  

A pattern emerged in my mind that is worth checking out, see the picture below:

In this variant, the tuning is the PUSH PUL circuit of the driver, which swings the parallel resonant circuit L1Cr. The winding of L1 can be made on a ferrite ring, through the hole of which the wire of the main resonant circuit is led out.  The main series resonant circuit is made according to the classical method of induction heaters, with the addition of the primary winding of an air transformer, which can be made on a system of flat coils.  In the secondary we have another series resonant circuit similar to the main one. 
Researcher Andriy Mishchuk and his experiments with resonant circuits based on "ZVS-driver" (Zero Voltage Switching) and current transformer pickup. According to my calculations he has about 30A-35A in the resonant circuit, consumption 4A.

"If you use an active load directly to the current transformer located on the wire coming from the capacitor, the consumption of the circuit from the source increases by a value comparable to the capacity of the load (lamp). The connection scheme was revised and one more ferrite ring (one more current transformer) was added.
In this case, the power consumption of three 12V/24W lamps does not affect the power consumption of the resonant circuit. The current consumption is 4 Ampere, both at no load and at connection of three lamps of the specified power. The lamps shine at full intensity. At connection of each next lamp, the brightness of the previous one changes insignificantly, the current consumption of the resonant circuit remains at the level of 4 Amperes."

Unfortunately, the author did not analyze the possibilities. The following questions remain unclear: what is the current in the resonant circuit; what is the power consumption of the circuit?  

The power of the connected lamps will be without heating: 24W*3=72W.
Let's assume that Andrew's power source was a 12V battery: 12V*4A=48V,(efficiency-1.5).
If the battery power supply is 24V, then 24V*4A=96W (efficiency-0.75). 

But we don't know what load we can connect.


Another idea has arisen, which I will present later, after verification.

The continuation follows, I will complete the material and my thoughts on the subject.


З повагою, Серж Ракарський!
Слава Україні, Героям Слава!


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