RESONANCE EFFECTS FOR EVERYONE TO SHARE

[duff]

Hi Gyula,

Thanks again for your input.

Two other thing in your simulation: 
1) Luc uses a signal generator that I assume has got a 50 Ohm output impedance and I wonder if you included it in your simulation as the inner impedance of your generator?

No, I did not account for that.

Actually I've never thought about how I would do that. If you could provide an example I would appreciate seeing how that is handled.

2) The coefficient of coupling (k) between your L1 and L2 can significanly influence the output towards load resistance (i.e. the bulb)  so I wonder what value you used in the simulation?  Seeing the photo of your coils I would say 0.5 - 0.6 for (k),  a rough guessing of course.  You (and probably Luc too) may have noticed when moving a little one of the coils away from or closer to the other, the output power (hence the brightness of the bulb) is changing accordingly.

Actually that was listed in the deck file:
k1 l1 l2 .9

I know that was too high  but the intentions were to just get close enough to give some kind of a base line as to what should be expected.

Moving the secondary up or down and optimizing its position relative to the current nodes along the primary is also a factor especially with the longer inductors.

My understanding on this setup in general is that the problem is how to utilize reactive power circulating in resonant circuits and the answer is not that easy at all:  at the moment I can only suggest studying Hector's rotoverter setups because the problem basically is the same, there are already so called "peak extraction" circuits that seem to be able to do it (at least in paper) but no any report on a successful VAR power extraction yet... 
Member esaruoho at energetic forum has addressed this same problem just today, his posts #235 and #236
http://www.energeticforum.com/renewable-energy/1507-roto-verter-8.html

Regards,  Gyula

EDIT:  just noticed you use R_lp=0.25 Ohm for the primary coil copper resistance and Luc stated 2.5 Ohm, right?  This has significance in simulation only if you did not use a 50 Ohm generator inner impedance because the figure of merit (i.e. the Q quality factor of L1)  comes out much higher in that case.

Yes, another slip of the pen. It was the wee hours of the morning when I did that sim -

Here's what I think I've determined...

As I stated before, in my replication attempt did not achieve the high voltages the simulation displays and my primary was not the same geometric shape as Lucs. If I rewind that inductor and get those kinds of voltages then it is says a lot about the geometry. Then perhaps I'll get the same output across the load.

Well, it's time to start winding inductors again....

-Duff

[Edit]
I corrected the error with the value of R_Lp on the previous page.
Also - left a comment regarding the coupling factor.

[najman100]

I was just responding to Gotuluc asking for our opinions , that is my opinion .

I like Gotoluc , he is Canadian ...

yeah write  go back to ionizationx and stay there and crack stainly meyers and as i told you i will build a monument for you in LAVAL .

Najman

[dankie]

yeah write  go back to ionizationx and stay there and crack stainly meyers and as i told you i will build a monument for you in LAVAL .

Najman

Sure , I feel ppl are smarter there ...

Have fun with the "resonance" , maybe add some "vacuum" while your @ it ...

[gyulasun]

No, I did not account for that.  Actually I've never thought about how I would do that. If you could provide an example I would appreciate seeing how that is handled.

Hi Duff,

Well,  if you simply connect a 50 Ohm resistor directly in series with your pulse generator in the schematic then you are done with this.  Normally spice based simulators use voltage source models with zero Ohm inner impedance so that they approach the ideal source with no any voltage drop across them and the user can choose any generator inner resistance.

Actually that was listed in the deck file:
k1 l1 l2 .9

I know that was too high  but the intentions were to just get close enough to give some kind of a base line as to what should be expected.

Now it was surely my turn to miss on that in your netlist  

[EDIT]
Update a mistake in netlist - changed R_Lp from 0.25 to 2.5 ohms
This really didn't make a difference in the waveforms - yes probably affected the circuit Q.

Yes it affects the resonant circuit Q but as I already indicated the moment you include the 50 Ohm gen resistance, the Q  will degrade significantly in the resonant circuit so you will not get those skyhigh voltage values across L1.  (In fact the generator should feed either a tap on L1 or another coupling coil as a matching means between 50 Ohms and the resonant impedance, this would be the first to achive for Luc also and the second goal is to match the lamp's impedance to the resonant circuit with L2 number of turns at a fixed coupling.)

Although not shown below I did try decreasing the coupling between the coils to 0.60. that resulted in an increase in amplitudes which is less believable.

But it is believable in case of the primary coil because reducing the coupling means less load on the primary hence its resonant impedance can increase, so can the voltage across it too.  In case of the secondary coil the output voltage (hence power) should decrease as the coupling decreases.

Regards,  Gyula

[duff]

Hi Gyula,

First - Thank you very much for your assistance and  insight with this simulation. I understand what you are saying, I just have not worked with spice that much - but I'll get up to speed. I'll try to do further updates tomorrow if this board doesn't cutoff my ability to modify that post...


@all

Some good news -

I rewound my inductors with #28 wire. This is a little smaller that Luc used but I am now getting results.

Here are the specs on the primary.
Turns: 145
L = 1.38mH & 1KHz
R = 8.26Ω

Secondary:
Turns: 9 , #18 speaker wire
L = 8.75uH @ 1KHz
R = 0.060 ohms


The coil form dimensions were as Luc specified on the previous page (Reply #49 )

The output is 1/2 wave rectified and filtered with a 10uF cap

Freq: 305KHz
R_Load = 63.3Ω
V_Load = 3.221V
I_Load = 50.885mA
P_Out = 163.9mW

Of course the above means nothing without the input numbers which are going to be more complicated because I have a real ugly waveform across my 0.68 ohm series resistor which I using to calculate the current (circuit driven with only function generator).

-Duff