High Voltage Forum
Tesla coils => Dual Resonant Solid State Tesla coils (DRSSTC) => Topic started by: Golddustpeak on May 14, 2019, 04:21:07 PM

OK so as I continue to think about my FGH60N60SMD full bridge system I'm thinking about these two coils.
One has a 1/8 inch tube primary and the other has a 1/4 inch tube primary.
Would either of these be a good choice for my DRSSTC system?
Comments please,
TNX
Coil #1 1/8 inch primary
J A V A T C version 13.4  CONSOLIDATED OUTPUT
5/14/2019, 8:07:22 AM
Units = Inches
Ambient Temp = 68ºF

Secondary Coil Inputs:

Current Profile = G.PROFILE_LOADED
1.5 = Radius 1
1.5 = Radius 2
1 = Height 1
16 = Height 2
1450 = Turns
30 = Wire Awg

Primary Coil Inputs:

Round Primary Conductor
2.5 = Radius 1
5.342 = Radius 2
0 = Height 1
0 = Height 2
6.429 = Turns
0.185 = Wire Diameter
0 = Ribbon Width
0 = Ribbon Thickness
0.0499 = Primary Cap (uF)
0 = Total Lead Length
0 = Lead Diameter

Secondary Coil Outputs:

226.51 [kHz] = Secondary Resonant Frequency
90 [deg °] = Angle of Secondary
15 [inch] = Length of Winding
96.7 [inch] = Turns Per Unit
0.00032 [inch] = Space Between Turns (edge to edge)
1138.8 [ft] = Length of Wire
5 [:1] = H/D Aspect Ratio
116.5578 [Ohms] = DC Resistance
42978 [Ohms] = Reactance at Resonance
0.35 [ lbs] = Weight of Wire
30.198 [mH] = LesEffective Series Inductance
30.457 [mH] = LeeEquivalent Energy Inductance
29.333 [mH] = LdcLow Frequency Inductance
16.349 [pF] = CesEffective Shunt Capacitance
16.21 [pF] = CeeEquivalent Energy Capacitance
22.644 [pF] = CdcLow Frequency Capacitance
5.9 [mils] = Skin Depth
14.262 [pF] = Topload Effective Capacitance
192.4825 [Ohms] = Effective AC Resistance
223 [Q] = Quality Factor

Primary Coil Outputs:

226.5 [kHz] = Primary Resonant Frequency
0 [%] = Percent Detuned
0 [deg °] = Angle of Primary
13.2 [ft] = Length of Wire
4 [mOhms] = DC Resistance
0.257 [inch] = Average spacing between turns (edge to edge)
1.317 [ inch] = Proximity between coils
0 [inch] = Recommended minimum proximity between coils
9.938 [µH] = LdcLow Frequency Inductance
0.05004 [µF] = Cap size needed with Primary L (reference)
0 [µH] = Lead Length Inductance
48.89 [µH] = LmMutual Inductance
0.091 [k] = Coupling Coefficient
0.126 [k] = Recommended Coupling Coefficient
10.99 [half cycles] = Number of half cycles for energy transfer at K
24.13 [µs] = Time for total energy transfer

Top Load Inputs:

Toroid #1: minor=3.5, major=14.5, height=16, topload
Coil #2 ¼ inch primary
J A V A T C version 13.4  CONSOLIDATED OUTPUT
5/14/2019, 8:05:32 AM
Units = Inches
Ambient Temp = 68ºF

Secondary Coil Inputs:

Current Profile = G.PROFILE_LOADED
1.5 = Radius 1
1.5 = Radius 2
1 = Height 1
16 = Height 2
1450 = Turns
30 = Wire Awg

Primary Coil Inputs:

Round Primary Conductor
2.5 = Radius 1
7.26 = Radius 2
0 = Height 1
0 = Height 2
6.295 = Turns
0.375 = Wire Diameter
0 = Ribbon Width
0 = Ribbon Thickness
0.0499 = Primary Cap (uF)
0 = Total Lead Length
0 = Lead Diameter

Secondary Coil Outputs:

224.01 [kHz] = Secondary Resonant Frequency
90 [deg °] = Angle of Secondary
15 [inch] = Length of Winding
96.7 [inch] = Turns Per Unit
0.00032 [inch] = Space Between Turns (edge to edge)
1138.8 [ft] = Length of Wire
5 [:1] = H/D Aspect Ratio
116.5578 [Ohms] = DC Resistance
42105 [Ohms] = Reactance at Resonance
0.35 [ lbs] = Weight of Wire
29.915 [mH] = LesEffective Series Inductance
30.385 [mH] = LeeEquivalent Energy Inductance
29.333 [mH] = LdcLow Frequency Inductance
16.874 [pF] = CesEffective Shunt Capacitance
16.613 [pF] = CeeEquivalent Energy Capacitance
23.416 [pF] = CdcLow Frequency Capacitance
5.93 [mils] = Skin Depth
14.662 [pF] = Topload Effective Capacitance
191.4953 [Ohms] = Effective AC Resistance
220 [Q] = Quality Factor

Primary Coil Outputs:

224.01 [kHz] = Primary Resonant Frequency
0 [%] = Percent Detuned
0 [deg °] = Angle of Primary
16.08 [ft] = Length of Wire
1.19 [mOhms] = DC Resistance
0.381 [inch] = Average spacing between turns (edge to edge)
1.222 [ inch] = Proximity between coils
0 [inch] = Recommended minimum proximity between coils
10.17 [µH] = LdcLow Frequency Inductance
0.04991 [µF] = Cap size needed with Primary L (reference)
0 [µH] = Lead Length Inductance
49.861 [µH] = LmMutual Inductance
0.091 [k] = Coupling Coefficient
0.126 [k] = Recommended Coupling Coefficient
10.99 [half cycles] = Number of half cycles for energy transfer at K
24.4 [µs] = Time for total energy transfer

Top Load Inputs:

Toroid #1: minor=3.5, major=14.5, height=16, topload

They would both be good :)
I would take the one with highest inductance as you are planning to use TO247 devices, so you can run lower peak currents but with a higher ontime, suits your IGBTs best IMO.
You primary capacitor is only set to 0.05 uF, that is pretty low and would call for even longer ontimes. With 0.075 uF on my DRSSTC2 I still find that it might be a tad too low.
I am looking forward to see your results, try to make a single thread with all your progress in for the project instead of making multiply threads for each question you have, just makes it easier for everyone to help you and for others to find the combined information in the future.

I’ve calculated and re calculated my system (keeping the fo around 225KHz) and cannot make a flat primary with more than 3 or 4 turns work with larger caps than my original 0.05 uF.
It seems to me that by going to a vertical primary I can make 0.15 uF work.
How does this look now?
New Coil:
J A V A T C version 13.4  CONSOLIDATED OUTPUT
5/15/2019, 8:46:08 AM
Units = Inches
Ambient Temp = 68ºF

Secondary Coil Inputs:

Current Profile = G.PROFILE_LOADED
1.5 = Radius 1
1.5 = Radius 2
1 = Height 1
16 = Height 2
1450 = Turns
30 = Wire Awg

Primary Coil Inputs:

Round Primary Conductor
2.5 = Radius 1
2.5 = Radius 2
1 = Height 1
5.934 = Height 2
6.3257 = Turns
0.375 = Wire Diameter
0 = Ribbon Width
0 = Ribbon Thickness
0.15 = Primary Cap (uF)
0 = Total Lead Length
0 = Lead Diameter

Secondary Coil Outputs:

222.43 [kHz] = Secondary Resonant Frequency
90 [deg °] = Angle of Secondary
15 [inch] = Length of Winding
96.7 [inch] = Turns Per Unit
0.00032 [inch] = Space Between Turns (edge to edge)
1138.8 [ft] = Length of Wire
5 [:1] = H/D Aspect Ratio
116.5578 [Ohms] = DC Resistance
37705 [Ohms] = Reactance at Resonance
0.35 [ lbs] = Weight of Wire
26.979 [mH] = LesEffective Series Inductance
30.035 [mH] = LeeEquivalent Energy Inductance
29.333 [mH] = LdcLow Frequency Inductance
18.977 [pF] = CesEffective Shunt Capacitance
17.046 [pF] = CeeEquivalent Energy Capacitance
33.051 [pF] = CdcLow Frequency Capacitance
5.95 [mils] = Skin Depth
14.724 [pF] = Topload Effective Capacitance
190.8735 [Ohms] = Effective AC Resistance
198 [Q] = Quality Factor

Primary Coil Outputs:

222.43 [kHz] = Primary Resonant Frequency
0 [%] = Percent Detuned
90 [deg °] = Angle of Primary
8.28 [ft] = Length of Wire
0.61 [mOhms] = DC Resistance
0.405 [inch] = Average spacing between turns (edge to edge)
0.807 [ inch] = Proximity between coils
0 [inch] = Recommended minimum proximity between coils
3.441 [µH] = LdcLow Frequency Inductance
0.15002 [µF] = Cap size needed with Primary L (reference)
0 [µH] = Lead Length Inductance
111.459 [µH] = LmMutual Inductance
0.351 [k] = Coupling Coefficient
0.126 [k] = Recommended Coupling Coefficient
2.85 [half cycles] = Number of half cycles for energy transfer at K
5.9 [µs] = Time for total energy transfer

Top Load Inputs:

Toroid #1: minor=3.5, major=14.5, height=16, topload

Mads wrote:
You primary capacitor is only set to 0.05 uF, that is pretty low and would call for even longer ontimes. With 0.075 uF on my DRSSTC2 I still find that it might be a tad too low.
@Golddustpeak:
I believe your questions can't be answered until you tell us more about the voltage your bridge runs with. The best primary impedance depends much on the bridges voltage and current capability. Mads DRSSTC2 has only a half bridge and is supplied with 120Vac. You have a full bridge and might want to run it with 230Vac, so that implies 4 times the voltage. So a higher primary inductance and lower capacitance primary than Mads had, might be in order for you.

Woops ........... Sorry
I'm thinking that I will be supplying the full bridge with a maximum of 230Vac.

Have a look at this thread: https://highvoltageforum.net/index.php?topic=113.msg657#msg657
A guideline for primary impedance is this:
Vmax/Imax ~ 0.5 * k / (2*pi*f*C)
For your coil, Vmax would be 230V * 1.4 = 320V and maybe Imax=300A. I'd choose as high coupling as possible, maybe around 0.2. That imples a primary impedance (i.e. 1/(2*pi*f*C) ) of about 11 Ohms. That would result in a 67nF primary cap. (Oops, sorry Mads, you weren't really off with your suggestion.) These are all ballpark values. The coupling coefficients in your first 2 calculations of about 0.09 seem too low. You should work on the geometry there. Low coupling coils can be made to work, but they are very sensitive to tuning issues.

THANKS...........
Great stuff which will get me off in the correct direction.
I've been called away from home for an emergency and will be away for a few weeks.
As soon as I return I'll start re calculating and be back with more questions.

Home for a day to run some numbers.
What do you all think about these numbers?
And is the system too much for my planned FGH60N60SMD full bridge system operated with 230Vac input?
J A V A T C version 13.4  CONSOLIDATED OUTPUT
5/25/2019, 9:29:14 AM
Units = Inches
Ambient Temp = 68ºF

Secondary Coil Inputs:

Current Profile = G.PROFILE_LOADED
1.5 = Radius 1
1.5 = Radius 2
1 = Height 1
16 = Height 2
1450 = Turns
30 = Wire Awg

Primary Coil Inputs:

Round Primary Conductor
3 = Radius 1
5 = Radius 2
0 = Height 1
4 = Height 2
6.75 = Turns
0.375 = Wire Diameter
0 = Ribbon Width
0 = Ribbon Thickness
0.075 = Primary Cap (uF)
0 = Total Lead Length
0 = Lead Diameter

Secondary Coil Outputs:

222.49 [kHz] = Secondary Resonant Frequency
90 [deg °] = Angle of Secondary
15 [inch] = Length of Winding
96.7 [inch] = Turns Per Unit
0.00032 [inch] = Space Between Turns (edge to edge)
1138.8 [ft] = Length of Wire
5 [:1] = H/D Aspect Ratio
116.5578 [Ohms] = DC Resistance
40371 [Ohms] = Reactance at Resonance
0.35 [ lbs] = Weight of Wire
28.879 [mH] = LesEffective Series Inductance
30.148 [mH] = LeeEquivalent Energy Inductance
29.333 [mH] = LdcLow Frequency Inductance
17.719 [pF] = CesEffective Shunt Capacitance
16.973 [pF] = CeeEquivalent Energy Capacitance
25.856 [pF] = CdcLow Frequency Capacitance
5.95 [mils] = Skin Depth
14.982 [pF] = Topload Effective Capacitance
190.8971 [Ohms] = Effective AC Resistance
211 [Q] = Quality Factor

Primary Coil Outputs:

194.4 [kHz] = Primary Resonant Frequency
12.63 [% high] = Percent Detuned
63 [deg °] = Angle of Primary
14.14 [ft] = Length of Wire
1.04 [mOhms] = DC Resistance
0.288 [inch] = Average spacing between turns (edge to edge)
1.596 [ inch] = Proximity between coils
0 [inch] = Recommended minimum proximity between coils
8.937 [µH] = LdcLow Frequency Inductance
0.05726 [µF] = Cap size needed with Primary L (reference)
0 [µH] = Lead Length Inductance
85.077 [µH] = LmMutual Inductance
0.166 [k] = Coupling Coefficient
0.126 [k] = Recommended Coupling Coefficient
6.02 [half cycles] = Number of half cycles for energy transfer at K
15.23 [µs] = Time for total energy transfer

Top Load Inputs:

Toroid #1: minor=3.5, major=14.5, height=16, topload

@Uspring, you are a champ, you always put the time into doing the math and I rely a bit too much on looking at the dimensions and reach for a gut feeling ;)
@Golddustpeak, as Uspring mentions, these are all ball park figures, nothing is set in stone once sparks are flying, the dynamic load on the system and quite a few assumptions from the construction does make it unnecessary to care about small differences between configurations that is less than 5% different.
With the coupling fixed in your latest JavaTC simulation I would say you are good to go, start building :)

I'm almost there.
Just a few more questions....
1) mmc:
CDE 940C20P15KF FILM 0.15UF 10% 2KVDC AXIAL
2 parallel strings of 4 in series for 0.075 µF
 or 
can I get by with 2 in series for 0.075 µF
2) I would like to use ass many off the shelf products as possible:
Current Transformers  Magnetics CST2061A for 1:100
Gate Drive Transformers  GT04111063B P0584NL
3) Gate Drive Resistors  15 ohms
4) OCD:
Is 300A too high or should it be set into the high 200s
Thanks again

1) I used 2 in series for my small DRSSTC and they have held up quite good despite some MIDI abuse, but if you got space/money, invest in the 8 capacitor MMC.
2) I got no experience with offthe shelf CT/GDT, simply because its so easy to make your own very sturdy, cheap from bare cores and cat5 ethernet cable. The 1:100 is only rated for 110Arms, you need something with a higher specification for 300Apeak.
3/4) I am not the most experienced with TO247 IGBTs, they blow up too easily to my taste ;) But I think you can do away with 510 Ohm gate resistors, but it really depends on your gate waveforms and you should make it easy to change them for another value.
There is really no difference between high 200 and 300, with these drivers, ground strikes and sudden changes in load dynamics, its all a +/ 100A game.

Hi Golddustpeak
Will you run your coil with full bridge +170VDC bus?
Be careful! the coil run on +170V haft brick, primary current easily exceed 250Apk while good tuning. I think your coil can not run on full bridge with FGH60N60SMD because primary current certain reached 400Apk. Do you think they suffers that threshold?

Yes I'm thinking that I will be supplying a full bridge with a maximum of 230Vac.
That's why I was wondering about adjusting the ODC to 300A.
I have not gone any further in design or construction due to forced trips away from home.