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Author Topic: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated  (Read 429963 times)

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1350 on: November 05, 2018, 02:56:40 PM »
Attached are two pictures.
The first shows the EMF waveform in a conventional generator with a North and South magnet alternately passing a coil.
The second shows a scope shot of the EMF (loaded), from a 600T test coil, about 5 slots wide placed inside the stator.
The main difference between waveform's, is the presence of signal during the inter-magnet period.

In the conventional generator, the signal during this period drops to almost zero however, in the DZ style generator, this period is occupied by the pulsed waveform, although the stator coils in registration with the test coil are not energized.

The only source of pulsing during this period is from the coils creating N & S poles, out of registration (up to 90 degrees) , see third picture that show the current on the coils at 90 degrees.The current clamp was just applied over the coil loops to show the relative time of current, so this is not a calibrated measurement of current.
I have not shown this, but placing the clamp over the coils in registration, shows there is no current on these coils during this period.
This reduces the magnitude of change, of the composite 60Hz waveform, resulting in reduced induction.
Each pole is 7 coils wide so the inter pole gap is 8 coils.

For this test coil there is a huge airgap, so its not clear why this flux is wanting to cross the gap. I also removed the coil core and repeated the test and it was the same.

This requires further investigation to understand why this is happening.     
L192

Jeg

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1351 on: November 05, 2018, 03:49:02 PM »
Hi. Just a small demo of the TTU v.1. Everything is ready for the funny part which is the programming. :)

30 primaries and 6 secondaries.
25 steps per half cycle right now. No limit in stepping. (The more the stepping the less the input current). Variable output frequency and input current. Variable input frequency.
Square wave output.
2 X PSU inputs for 24V, 12V, and 5V supplying.


https://www.youtube.com/watch?v=t6xv7qhcdTM&feature=youtu.be

Regards

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1352 on: November 05, 2018, 04:11:19 PM »
Hi. Just a small demo of the TTU v.1. Everything is ready for the funny part which is the programming. :)

30 primaries and 6 secondaries.
25 steps per half cycle right now. No limit in stepping. (The more the stepping the less the input current). Variable output frequency and input current. Variable input frequency.
Square wave output.
2 X PSU inputs for 24V, 12V, and 5V supplying.


https://www.youtube.com/watch?v=t6xv7qhcdTM&feature=youtu.be
Hi Jeg,

Substantial build and you stuck with the alternative design, respect for that!
This should have the advantage of keeping the flux in the stator, until in registration with the rotor.

Regards
L192

Jeg

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1353 on: November 05, 2018, 05:42:48 PM »
Thanks L192.
Device has designed with no intention of using internal fixed coil. In the video i take the output through 6 of the coils, all in parallel. But I can also use the primaries as secondaries the same time. In general many options for testing. I use low side and high side switches some of them with back to back mosfets as it has been discussed before some pages.
Overlapping pulses at the one third of the pulse.
15 coils driven as CW and 15 coils as CCW.
I have already used between 500 and 10 steps per half cycle. As I said the more the steps the less the input current.

Regards
 


listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1354 on: November 06, 2018, 02:23:46 PM »
I adjusted the proportions of my FEMM model to more accurately represent my stator.
Driving the 2 x 7 coils at 1.5A average (this would be a much higher pulse current) each, brings the stator up to 1.5T and the start of saturation for M15 steel.

I modeled a 0 deg and a 90 deg case (note: coils relative to rotor). Easier to fix the coils and move the rotor. In the 90 deg case you can see that there is no flux through the rotor, only a very low air coupled flux (0.045T) through the side of the rotor.

Also attached, shot of coil composite coil current (dark Blue) & output EMF (loaded). Used a large current sensor around the coil cables.

Further measurement shows that there is a primary power supply current draw that is coincident with this period but does not show up coincident with the composite coil current.
I will start working through the individual bridges to determine which ones are responsible for this.
 

L192
« Last Edit: November 06, 2018, 09:19:17 PM by listener192 »

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1355 on: November 08, 2018, 09:34:14 PM »
Attached is a slightly improved waveform, more symmetrical which produces a fairly good sine when filtered.
This was achieved by fine  adjustments in code delays. I achieve about 150W maximum output with this waveform but for about 450W DC input, so pretty inefficient.
A vast amount of power is being dissipated as coil heat.  You can see from the voltage and current waveforms that the 60Hz wave front is reasonable well formed.

I checked the coil currents for those in registration with the rotor and those at 90 degrees to the rotor. Interestingly, I found both to be almost identical in amplitude, not what I was expecting, as the coils not in registration should be of lower inductance due to lack of the rotor flux coupling.

This implying that a varying flux is established in the stator that is fairly uniform and that the rotor does not offer an appreciably lower reluctance path, as far as this flux is concerned.In an AC  generator with a DC energized rotor, there is a point coupling of flux onto the stator teeth in registration , it is a single flux that does not compete with any other flux (ignoring lenz for the moment).

The  flux spreads out around the stator in both directions and is at right angles to all of the stator coils, only where the rotor flux couples with the stator teeth, are those coils subjected to a changing flux  that produces induction.

Is this flux totally uniform or is there something happening in the direction of rotation along the stator?

Well yes there is and this is normally referred to as armature reaction, see attached diagram.

Note how the flux crossing point from rotor to stator is skewed in the air gap, the lines of flux trail behind the turning rotor.

In an AC generator, the effect of armature reaction depends on the power factor i.e the phase relationship between the terminal voltage and armature current. Reactive power (lagging) is the magnetic field energy, so if the generator supplies a lagging load, this implies that it is supplying magnetic energy to the load. Since this power comes from excitation of the rotor, the net reactive power gets reduced in the generator. Hence, the armature reaction is demagnetizing.

Similarly, the armature reaction has magnetizing effect when the generator supplies a leading load (as leading load takes the leading VAR) and in return gives lagging VAR (magnetic energy) to the generator.

As in this case both armature flux and rotor flux lead, induced emf E by 90o, it can be said, rotor flux and armature flux are in the same direction. Hence, the resultant flux is simply arithmetic sum of rotor flux and armature flux.

In case of a purely resistive load, the armature reaction is cross magnetizing only.

Now, how much of the above is reproduced  in the DZ?

L192
« Last Edit: November 09, 2018, 03:52:17 AM by listener192 »

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1356 on: November 09, 2018, 02:08:27 PM »
Simple answer to the coil current issue.

As I am running the coils in series albeit each coil is also in parallel with an opposite coil, of course the current is shared, so the coils not in registration do not contribute to output but have limited inductance and their resistance will consume power.
Compare this to a generator with rotating flux source and you find that it is similar, with several stator coils in series forming a distributed winding (to produce a better sine). So some of these coils will be out of registration and will only have limited inductance and losses due to resistance.

 L192

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1357 on: November 11, 2018, 08:22:45 PM »
On Saturday, I discovered I had a few shorted turns on my rotor coils. I removed all wire and modified the rotor so I could wind some additional turns.
I have rewound with 0.8mm wire but still need to add some more turns to get the 230V operation I desire.

I achieve about 165V RMS with what I have wound on so far, but decided to try a load first before winding more turns on.
Increasing the load now results in step increases in output power, where before there was a maximum load achieved then further increases would result in a decrease in output power.

No magic break through however, the shorted turns were certainly impeding performance.
The 0.8mm wire is a slightly heavier gauge than the wire I removed and I see that has helped reduce the IR loss a bit. That caused me to ponder on the gauge that Pierre used, which in the first video is shown as 20AWG which is close to 0.8mm however,  Pierre's wire is quiet stiff and supports the line outlets. On that basis, I think the gauge must be closer to 1mm or 18AWG, which will make a significant difference to the current versus volt drop on the rotor windings.

For 700ft wire length the 18 AWG wire resistance would be 4.799 ohms instead of 7.109 ohms for 20AWG.


 L192

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1358 on: November 13, 2018, 05:45:12 PM »
Here is a quick check on my current build performance.

INPUT              OUTPUT          RECOVERY
117.5W Av       29W Av          32W Av@25V

224W Av          59W Av          67W Av@35V

373.5W Av       91.7W Av        110W Av@45V


Note: @50V, the max output with the same load used for these tests, is about 138W

The boost recovery circuit is working reasonably.
The ratio of input to output is constant.

A check on flux linkage using 7 + 7 coils in series/parallel energized with 50Hz sine indicates about 0.89%, (close to reasonable transformer operation), which ties up with the recovery to output ratio.
Obviously the input current is way too high, likely due to holding coils on for 7 steps.

It all comes down to generating the advancing MMF wave front in the stator with the overlapping coils.

The low turns value for each coil (35) in combination with parallel coil operation is required to get current to rise in the coil within the step period. This is at odds with what is required once a flux level has been established in the stator. The flux could be maintained by coils with a large number of turns and a lower current however, these coils would be problematic as they would present a high inductance to overcome to rise the current during the step period.

If a sine current were applied to these 35T coils to establish flux linkage  i.e 100W input (88W output), then a pulsed composite signal is established on top of the sine current, synchronized in phase.
We know that at least 80% of this pulse portion of the output could be recovered.
We also know that recovery energy is proportional to load, so the real question with this scenario, is what happens to the overall input current when it is always increasing or decreasing due to the slope of the sine i.e there is no time that current is static?

Note: this would not be using half sines as the input voltage for the switches. 

I have not figured out how to apply the current sine to the coils yet.


L192
« Last Edit: November 13, 2018, 09:09:09 PM by listener192 »

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1359 on: November 14, 2018, 10:01:30 PM »
Attached is a waveform close to what I am trying to achieve. I still don't have a good circuit to achieve this yet. The actual waveform would be the stepped one with the trailing pulse in the pole being sequentially turned off.
This time for each coil in the series chain that is on for more than one step, a current slope is present. The pulses generate recovery when they turn off. This recovers at least 80% of the energy stored in the coil.
The continual current slope, should provide transformer like flux linkage performance.

The second shot may be a little closer, as the pulses maintain more amplitude down to the zero cross point.

L192
 

T-1000

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1360 on: November 16, 2018, 07:27:03 PM »
@L192 Hi :)
It is nice you still keep it going.And when looking all way back where essence is you might actually try to make coil arrangement where magnetic field could smoothly shift from one driving coil to another for simulating moving magnet. Like back in old TPU days... The rule of the thumb for induction is the rate of change and the drag for current strength.

P.S> Personally I paused a project due other priority things in life but will continue on it at some point as well.
Good luck!

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1361 on: November 16, 2018, 08:50:18 PM »
Hi T-1000,
Thanks for your encouragement.
The geometry of the DZ does not support energized stator coils to achieve flux cutting in the rotor, as there is no perpendicular path.
I have looked at architectures that would support flux cutting utilizing a stator and the only one I can describe, uses a circular rotor with teeth around the periphery.

If you energize coil on such a rotor, the flux will cross into the stator flow left and right around the stator.

Consider a small flux level.. the flux will take the shortest path around the  inner edge of the stator. As the flux level is increased, the flux lines compress and will move outward to increase the flux density in the mid portion of the stator.

Add even more flux and the outer portion of the stator becomes full with flux lines. This process progressively cuts the coil windings on the stator teeth at 90 degrees, so this becomes the direction of movement using right hand rule and because the flux will flow through both sides of the stator coil in registration, the direction of electron flow (looking up at the coil from the middle of the stator) is anti-clockwise on both coil edges. 

Physical movement is not necessary to achieve the above however, what benefit this derives I am unsure as both flux linkage and flux cutting are subject to lenz.In the above example, as a current is induced in the stator coil due to a connected load, lenz law will cause a counter flux to be setup that will oppose the flux coupled from the rotor.

In the case of the DZ, my current thought is on being able to make the stepped waveform behave like a sine current in a flux linkage configuration. Once that has been achieved i.e. normal transformer operation, then the magic would be in the recovery of the energy stored in the magnetic field, given up every time a coil turns off. So 100W input yeilds  say 85W output but 80% of this is recovered ..68WInput =100W-68W =32W for 85W output.

At the moment the coils behave as DC solenoids, once current has risen in the coil, in particular when they are on for several step periods. This wasted energy appears as heat due to the coil IR losses. At the moment, the only way I can see to counter this, is to keep inductance present, to limit the current by keeping the current changing during the coil on periods beyond the initial current rise. This is the idea of the sine current application. Using half sines as the supply rail for the switches may also achieve the desired result. Initially I dismissed this due to an experiment conducted using the bridge boards however, there were two many other problems that stopped that attempted working properly.
The impediment to making this work is the synchronization of the stepped waveform with the zero cross of the half sines. Before I used an interrupt structure with case statements and a zero cross detector. This allow the interrupt to call the start of the stepped waveform routine. There was a problem however described below that was never resolved.

My current scheme uses delays in the code for the HSS delays, required as the opto couplers are slow to switch the MOSFETS. The use of delay in an interrupt driven routine is not possible as they use internal timers with interrupts, and these get turned off. Perhaps polling a pin for zero cross would be better, as delays could be kept for timing the steps.

If you model the 150uF cap that Pierre has across his FWBR, you see well developed half sines.  This is what he is feeding his relays with, so I believe this is significant.


Regards
L192

FixedSys

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1362 on: November 17, 2018, 11:34:36 AM »
The geometry of the DZ does not support energized stator coils to achieve flux cutting in the rotor, as there is no perpendicular path.

Is it possible that in addition to linking; flux cutting is achieved through the distortion of flux from armature reaction and / or other fields?
It would appear that flux distortion is the only way possible to properly move flux to achieve cutting. Perhaps there's distortion occurring in sympathy with the 60 Hz or harmonic, and perhaps the OU is found in a combination of linking and cutting?

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1363 on: November 17, 2018, 01:57:27 PM »
Flux cutting occurs in a generator with a physically rotating rotor, irrespective of armature reaction.
The rotor flux flows into the stator and distributes left and right around the stator. As the rotor  moves across a given coil the flux level increase and cuts both edges of the coil however, it is the increase in flux density across the coil that causes induction, as this is the effective movement into the coil (right hand rule applies). If the rotor was static, flux cutting could still occur if the flux level in the rotor was changed by a rise and fall in rotor coil current.


In the DZ, the flux from a stator coil enters the rotor but there is no path at 90 degrees to the rotor coil, so the flux passes through the center of the coil, changing the flux density hence producing induction by flux linkage.

Flux cutting offers no advantage over flux linkage.

L192

listener192

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Re: Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated
« Reply #1364 on: November 17, 2018, 07:57:07 PM »
Line Synchronization:
I tried polling a digital pin to look for the rising edge of a zero cross pulse but this was way too slow.
I have achieved locking the stepped sine waveform to an interrupt. I moved the stepping code from the loop and placed it in a named ISR. The loop remains empty.I replaced any delay commands with delayMicroseconds, which don't use interrupt timers.
Just using a square wave from a function generator (purple waveform), I locked the stepped sine to 50Hz.
There is a bit of phase shift between the two signals which is because my original code did not start the waveform at zero. The pot input delay setting was used to get the frequency in the ball park.

I have a zero cross detector to connect next.
 
L192