Complications in the design of the first DRSSTC

[PEDRO HENRIQUE]

I want to build a DRSSTC but I'm having some complications, in the moment I want to know how can measure the values of primary coil and the value of the capacitor that goes in series with the primary coil.

Can some one teach me how to measure these values?

[thedoc298]

Look for and download javatc. It is a design program for tesla coils. If you want to measure  what you have, just run the program and fill in the blanks with your data. Take a bit to figure it out, but well worth the time.+

[Mads Barnkob]

For all these questions, I wrote a very large guide on designing a DRSSTC. It is from a practical point of view with the minimum required math and a lot of best practices / experimental best results.

All at https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/

Among the online tools is also JAVATC that I recommend using.

[PEDRO HENRIQUE]

Thank you, I will read this, but while I'm reading, I will let here a question about the IGBT that I chose.

I want to use the CM300DU-24H:

Collector-Emitter Voltage (G-E SHORT) VCES 1200 Volts
Gate-Emitter Voltage (C-E SHORT) VGES ±20 Volts
Collector Current (Tc = 25°C) IC 300 Amperes
Peak Collector Current (Tj ≤ 150°C) ICM 600* Amperes
Emitter Current** (Tc = 25°C) IE 300 Amperes
Peak Emitter Current** IEM 600* Amperes
Maximum Collector Dissipation (Tc = 25°C) Pc 1130 Watts

Resistive Turn-on Delay Time td(on) VCC = 600V, IC = 300A, 200 ns
Load Rise Time tr VGE1 = VGE2 = 15V, 300 ns
Switch Turn-off Delay Time td(off) RG = 1.0V, Resistive 300 ns
Times Fall Time tf Load Switching Operation 350 ns
Diode Reverse Recovery Time trr IE = 300A, diE/dt = -600A/µs 300 ns
Diode Reverse Recovery Charge Qrr IE = 300A, diE/dt = -600A/µs – 1.65 – µC

I want to know if this IGBT is enough to withstand a 1000V bus voltage, I was thinking of making a coil with a power of 13000W, but the only thing I want it to have is 1000V bus, the power can be different.

[davekni]

You are likely to fry 1200V IGBTs at 1000Vbus due to voltage transients.

It theoretically would be possible with extreme effort and skill - properly adjusted phase lead, sufficient dead-time, regulated Vbus to never exceed 1000V, and extremely-low-inductance H-Bridge construction.  If you really want to try, here's one option for low-inductance H-Bridge construction:
https://highvoltageforum.net/index.php?topic=1324.msg11785#msg11785

[PEDRO HENRIQUE]

You are likely to fry 1200V IGBTs at 1000Vbus due to voltage transients.

It theoretically would be possible with extreme effort and skill - properly adjusted phase lead, sufficient dead-time, regulated Vbus to never exceed 1000V, and extremely-low-inductance H-Bridge construction.  If you really want to try, here's one option for low-inductance H-Bridge construction:
https://highvoltageforum.net/index.php?topic=1324.msg11785#msg11785

even if I use measurements against transient voltages?
(For example, TVS)

And what is the best Vbus and the highest power(Watts) to use with these IGBTs?

Note: I'm relatively new to electricity and I don't have a lot of money to spend buying new IGBTs, so I don't intend to risk that much.

[AstRii]

Problem with all these protections against voltage transients like RC snubbers or TVS diodes is that it doesn't necessarily clamp the voltage as one might think. TVS diodes can be slow and with a sufficient voltage transient you can overheat them which results in short circuit and afterwards the destruction of your IGBT bridge. You can't even rely on RC snubber networks. Also your protection components are still a few centimeters away from the IGBT chip itself. A few cm of wire is a lot of inductance when dealing with such a high frequencies and currents.

When I'm designing a circuit I'd like to keep my transistors breakdown voltage 2x the switching voltage to have a nice headroom, even in soft-switching applications. So for a 1200V IGBT I would probably use 600V maximum. Some braver people would go even higher (maybe 800V?).
I would recommend you to use rectified 3phase AC voltage for 564V bus (assuming you have 400VAC between 2 phases).
How would you even get 13kW at 1000V anyway? Such a power supply would be even more difficult to build than the coil itself.

[PEDRO HENRIQUE]

I would recommend you to use rectified 3phase AC voltage for 564V bus (assuming you have 400VAC between 2 phases).

I don't know how much VAC I have between two fases, but I would appreciate it if you would tell me how I find this out.

How would you even get 13kW at 1000V anyway? Such a power supply would be even more difficult to build than the coil itself.

13kW is just a power estimate which I thought would be normal for a DRSSTC, but this can be changed, I just want to get as much power as possible (safely) with these IGBTs.

So, the tesla coil that I want to build have this
parameters (I determined only the primary coil, secondary coil and the IGBTs):

The primary have

Internal diameter: 410mm
number of turns: 10
wire diameter: 10.39mm (AWG 000)
Space between turns: 20mm
External diameter: 1017.8mm
Wire Length: 22.428m
Inductance: 80.927uH
this is the site i used to calculate these parameters: http://www.energylabs.com.br/el/calculadora/spiral

The secondary have

diameter: 360mm
height: 2.048m
number of turns: 2000
wire diameter: 1.024mm
Inductance: 230.876,11uH

this is the calculation I used to find the inductance:  L= ((a^2)*(N^2))/(25,4*(9a*10b))

L: inductance, in microhenry (µH).

a: coil radius, in millimeters (mm).

b: coil length, in millimeters (mm).

N: number of turns of the coil (pure number).

I don't know if it is right, but I got this calculation from this site: https://blog.render.com.br/eletronica/bobinas-de-uma-camada-com-nucleo-de-ar/

Note:  m = meters      mm = millimeters

Note 2: the IGBTs are in a previous post.

So, with these informations, what is the highest voltage and the highest power (in Watts) I can use(safely)?

Note 3: when I said safely, I meant something without complications that will make something burn, because I don't have the money to buy the components again.

[AstRii]

Measure the voltage between 2 phases of your mains AC with a multimeter, but of course.. be careful!

It's not that easy to say what power will you be able to push through your coil. That depends on so many factors that I wouldn't even have the courage to guess.

But I'm still very interested about where would you get a very higher power PSU that outputs 1000V. Some kind of voltage multiplier?

[PEDRO HENRIQUE]

Measure the voltage between 2 phases of your mains AC with a multimeter, but of course.. be careful!

ok, I will try it.

It's not that easy to say what power will you be able to push through your coil. That depends on so many factors that I wouldn't even have the courage to guess.

I'm still learning, so if you can teach me, I would appreciate it.
What I have to know at first to learn to build a DRSSTC?

But I'm still very interested about where would you get a very higher power PSU that outputs 1000V. Some kind of voltage multiplier?

I would make two high power transformers and put them in series, so I would use 380V 63A from my network, so that after going through the transformers it would have 1000V, of course my power network doesn't have this capacity yet, but I would ask to the energy provider to change my power network to three-phase and to a higher power

[PEDRO HENRIQUE]

For all these questions, I wrote a very large guide on designing a DRSSTC. It is from a practical point of view with the minimum required math and a lot of best practices / experimental best results.

All at https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/

Among the online tools is also JAVATC that I recommend using.

Mads

I have been reading your guide (https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/), but there are somethings I don't understand.

I don't know what is BPS, if you can say me what is BPS, this will help me a lot.

And where those currents of thousands of amps come from?

In the guide, you used a CM600 as an example, and in the guide you say that you will switch 2000A with that IGBT, and I didn't understand how does the CM600 can handle this power, since the CM600 is built to handle 1200V 600A and 1200A in pulse.