Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated

[listener191]

Thanks for your reply Slider2732 but I'm going to need a little more than that.
If I was to connect all 30 L298N I would need for someone who knows the program and better knowledge in electronics to tell me which boards can be grouped together so the 120 wires can connect in the Arduino which only has some 50 or so connections. See the the problem?

Now if L192 suggestion of using 18 L298N is capable of handling the same amount of current as 30 L298N and I only need to deal with 72 wires to the Arduino instead of 120 then I would rather go that route.
I need help one way or the other and 18 sounds a lot easier to deal with then 30.
So are you or anyone else ready to help me with this part to see what this device will do?
Regards
Luc

Fr. Merci pour votre réponse Slider2732 mais je vais avoir besoin d'un peu plus que ça.
Si je devais connecter les 30 L298N, il faudrait que quelqu'un qui connaisse le programme et de meilleures connaissances en électronique me dise quelles cartes peuvent être regroupées pour que les 120 fils puissent se connecter à l'Arduino qui n'a qu'une cinquantaine de connexions. Voir le problème?
Maintenant, si la suggestion L192 d'utiliser 18 L298N est capable de gérer la même quantité de courant que 30 L298N et j'ai seulement besoin de traiter 72 fils à l'Arduino au lieu de 120 alors je préfère aller dans cette voie.
J'ai besoin d'aide dans un sens ou dans l'autre et 18 sons beaucoup plus faciles à traiter que 30.
Alors êtes-vous ou quelqu'un d'autre prêt à m'aider avec cette partie pour voir ce que cet appareil va faire?
Cordialement
Luc

Hi Gotoluc,

30 L298N H bridges individually connected to 30 coils would be 2A per coil, 60A in total, whereas with the series scheme there are 3 current paths running through three half bridges, each handling 3.5A or 10.5A in total... big difference.

Regards

L192

[Slider2732]

Luc - I did think there was a circuit to follow with the 30 modules, but if not and if they can cope with the needed amperage via L192's design, it makes sense to do that.
We're lucky to have such input as his in my opinion. Pierre used relays, so it's a case of what can work effectively.
The changes to the code are something I can do, or help with, as i'm sure others will
Now, yes, it becomes a case of what gets soldered to where.
Is there a flowchart or diagram of circuit path ? for example how the diode recovery gets back to the supercaps ?
There may be areas that can be soldered up while waiting for a full circuit diagram or the code changes.

[gotoluc]

Hi Slider2739,

I received a  personal message from pmgr and he is wiling to help map out all the connections for me according to the 2560 programs timings.
As for the coil recovery diodes, I already asked about that on page 8 and L192 has replied and said the L298N have recovery diodes built into the board
http://overunity.com/17653/pierres-170w-in-1600w-out-looped-very-impressive-build-continued-moderated/msg518983/#msg518983
I guess somehow the coil recovery will go back through the power rails and evened out by the super capacitors.

Regards
Luc

Fr. Salut Slider2739,
J'ai reçu un message personnel de la part de pmgr et il est prêt à aider à établir toutes les connexions pour moi selon les horaires des programmes du 2560.
En ce qui concerne les diodes de récupération de bobine, j'ai déjà demandé à ce sujet à la page 8 et L192 a répondu et dit que le L298N ont des diodes de récupération intégrées dans la carte
http://overunity.com/17653/pierres-170w-in-1600w-out-looped-very-impressive-build-continued-moderated/msg518983/#msg518983
Je suppose que la récupération de la bobine reviendra en quelque sorte à travers les rails d'alimentation et compensée par les supercondensateurs.
Cordialement
Luc

[konehead]

Hi Luc and everyone
Just my two cents and disregard if you "don't think so"(no problem)  but it scares me a bit with those modules with their "built in" recovery diodes....as I am thinking where do they go to?

Is there an external "collector" capacitor that collects the backemf/recoil/flyback energy via those steering diodes  and this collector capaciyor  is then pulsed out to load (for example)s after 4 pulses filling them, the...load in this case would be the supercaps

To fill up super-caps "straight" from backemf/recoil/flyback steering diodes usually does not work very well, since the caps being so large of UF will act like a resistive load to the backemf/recoil energy steered out through the  steering diodes....and so this immediately reflects back to lurch up the primary input to much larger draw and it just becomes a big loss to system...I am sure any of you working with flyback/backemf energy know this - and what needs to be done is proper size UF cap needs to be filled, and this cap filled all by itself, with no resistive load over it too.....then this cap is periodically discharged to a load (so cap does not fill up and stay filled up otherwise being filled up it will stop collecting the backemf/recoil energy!)

And important this collector cap must be disconnected from the steering diodes and/or switching whenever it does discharge, or the discharge reflects back to the primary, and it goes up in draw terrible ....(anyone who has worked with backemf/flyback energy also knows this)
This is called a two-stage cap discharge output...pretty common stuff really....

Anyways I cannot believe those built in diodes in those modules will do anything at all but to suppress the backemf/flyback energy and snuff it out so it will not disturb the electronics in the modules and this would be the normal thing to do - ususally the designer will steer the energy straight back into the inductor, snuffing out the :"destgructive transients" that way - and I will suppose that is all those modules will do too, with their built-in diodes...

So I think how Pierre has external steering diodes mounted to his relays to recover the backemf/recoil energy into the supercaps will be actually recovering that backemf/recoil energy and helping the super caps stay stocked up in joules, keeping the system looped and self-sustaining....
(at least helping it to)
While I think those modules will only suppresss and snuff out the backemf/recoil energy, adding nothing to the supercaps...
The supercap UF value might not be such a factor, since Pierre pre-charges those caps, and the caps being already high in voltage will make them more receptive to recieveing and capturing the backemf/recoil energy - that is all I can think of as to how it can actually work OK

One more thing - having modern "ultra fast" or even better "hyper fast" diodes as the backemf/recoil recovery diodes could make the system even better....at least I hiope those are shottkys but there are even better diodes out nowadays....look up the hyper fast ones....

So that is my two cents sorry!
Please continue everyone how you are all doing great!!!!
I like this moderated board it was quite ridiculous the arguments and accusations and eventual sabotage of this project by the usual dickweeds ....

[pmgr]

Hi Luc,




Edit: just realized I did this originally for 36 slot rotor. Edited below now and fixed for 30 slot stator.
Edit 2: updated for enable pins.

I don't have time today to make a drawing but a description should work as well.

Each coil has two leads, input lead A and output lead B, so e.g. Coil 1 has leads C_01A and C_01B, coil 2 has leads C_02A and C_02B, etc.... Coil 30 has leads C_30A and C_30B. The leading C_ stands for Coil. We will use H_ for the H-bridge and A_ for the Arduino.

The Arduino has 54 digital I/Os. We are going to use only 30 of them (for 30 coils): A_01 through A_30.


Each of the half bridge has 6 inputs: Inputs 1 through 4 and Enable A and Enable B. Remove the Enable A and B jumpers  (so they are NOT connected to Vcc). Input 1,2 should be connected to Vcc, input 3,4 to GND. ENA and ENB should be connected together as we are going to activate both the high (Vcc) FET and the low (GND) FET at the same time to activate a set of 5 coils. You already have all coils connected in series on the stator, so you can leave that in place.


So let's call the EN inputs that are connected together H_01I for bridge 1, H_02I for bridge 2, etc. through H_30I. The I stands for input.

The H-bridge has 4 outputs. Output 1 and 2 are connected together and Output 3 and 4 are connected together (for double amps). Let's now assign these two resulting outputs as H_01A (for output 1-2) and H_01B  (output 3-4).

Then the connections you will need to make are:

A_01 output to input H_01I, and outputs H_01A to C_01A and H_01B to C_05B (so five coils in series)
A_02 output to input H_02I, and outputs H_02A to C_02A and H_02B to C_06B
etc.

A_29 output to input H_29I, and outputs H_29A to C_29A and H_29B to C_03B
A_30 output to input H_30I, and outputs H_30A to C_30A and H_30B to C_04B

That's it. Just label all the wires accordingly so you can easily find back wires later on.

I note a few things. Please also see the datasheet of the L298N:

https://www.sparkfun.com/datasheets/Robotics/L298_H_Bridge.pdf

Each output of the L298N can carry 2Amps of current max (maybe 2.5-3amps at 1/12 duty cycle but let's use 2amps for now). Since we hooked two outputs together, each of the outputs H_01A and H01B can supply or sink 4Amps of current.

Each of your coils has about 0.5ohms resistance. We are driving 5 coils in series, so that is about 2.5ohms total per coil.

However, we are activating 6 poles with 6 FETs (3 on the high (Vcc) side and 3 on the low (GND) side, see the image in reply #9).

So e.g. we would activate A_01, A_11 and A_21 on the Arduino which will activate H-bridge H_01I, H_11I and H_21I and coils C01A-C05B, C_11A-C_15B and C_21A-C_25B with forward current and coils C_06A-C_10B, C_16A-C20B and C_26A-C_30B with reverse current.

This makes the 6 poles. One each subsequent Arduino step, everything shifts by one:

We would activate A_02, A_12 and A_22 on the Arduino which will activate H-bridge H_02I, H_12I and H_22I and coils C02A-C06B, C_12A-C_16B and C_22A-C_26B with forward current and coils C_07A-C_11B, C_17A-C_21B and C_27A-C_01B with reverse current[/size].
etc.

I note that because of this configuration (Which is the same as Pierre is using), the current that each FET supplies is split into two coilsets (5 series coils per set, let's call it a 5-coilset). So e.g. the FET at coil 1 (H-bridge output H_01A) provides current to two coils sets (5-coilset C_01A-C_05B and 5-coilset C_26A-C_30B). Since the resistance of each 5-coilset is 2.5 ohms, the current will be split equally, so 2Amps max per 5-coilset.

At each point in time there are 6 poles on (each pole has 2 5-coilsets), so total current draw will be 6x2amps=12amps max.

The max voltage over one 5-coilset is 2.5ohms x 2amps = 5 volts. So you should not be driving your coils with anything higher than 5 volts, otherwise you will burn out your FETs.

So this confirms Pierre's concern about the H-bridges not being able to provide enough current. But I think this is good for an initial try to see if we can make a rotating magnetic field.

Let me know if you have any questions or if things are not clear.

PmgR
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