Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Weston

Pages: [1]
1
Electronic circuits / Re: Si-wafers, ideas?
« on: June 25, 2019, 07:07:57 AM »
Assuming you lack access to a clean room, I have heard that simple bipolar transistors are possible to make at home with a diffusion process. However, actually making any active device is going to be difficult, obtaining wafers is the absolute easiest part of the process.

You can have fun cleaving the wafers. If you apply pressure with a hard point in the right orientation relative to the flat of the wafer you can split the wafer with atomic level precision.

Other than that, silicon has pretty good transmission in the IR region. A thermal camera should be able to see through it and a CO2 laser should be able to somewhat shine through it.





2
Dual Resonant Solid State Tesla coils / Re: cute-qcw Tesla Coil
« on: March 18, 2019, 07:55:52 PM »
Some mechanism is needed to provide phase lead and allow for zero current switching.

In some designs inductive loading is added to the CT so provide phase lead in the analog domain. The UD 3.0 driver adjusts a timer to switch the inverter based on the timing of the last ZCS transition, which is similar to a phased locked loop approach. Other FPGA based controllers have implemented phase lead in the digital domain with a FIR/IIR filter, but this requires more logic resources and a high speed ADC.


The two scope shots are with the same system parameters. I suspect that some noise is causing the PLL to lock on to some other operating frequency that leads to a different voltage distribution on the secondary and leads to the flashover between the middle of the secondary and the primary. I think that the flashover itself is leading to some system parameters changing (secondary effectively partially shorted),  and the PLL tracking this new resonant mode causes the sudden increase in current.

I suspect by altering my PLL loop gain and adding a bit more digital filtering of the ZCS signal I can eliminate this issue, but I will see if I can get higher resolution scope shots showing that frequency the PLL is locking on to.

3
Dual Resonant Solid State Tesla coils / Re: cute-qcw Tesla Coil
« on: March 16, 2019, 08:04:52 PM »
I forgot to say, but the coil uses a phase shifted fullbridge for modulation. Right now I am running at a 10ms burst and hitting a peak tank current of ~60A.


The FPGA logic runs at 240MHz. It may have been due to some other factors which I eliminated in debugging, but I was having issues with PLL stability which I thought may have been due to the limited frequency resolution of the counter generating the gate drive signals, so I bumped it up to 240MHz from 160MHz. 

I think my PLL may occasionally still be mis-locking, causing the coil to operate in some mode that leads to primary - secondary flashover. I managed to capture waveforms of both a normal discharge and a flashover (yellow: inverter voltage, blue: current), when it flashes over you can see that there is a high current pulse, but from the start of the pulse the current is lower, implying that something is wrong with the pulse from the start.

Normal Pulse:

Flashover Pulse:




4
Dual Resonant Solid State Tesla coils / cute-qcw Tesla Coil
« on: March 16, 2019, 06:01:44 AM »
Hi All,

I have been working on a FPGA based qcw tesla coil driver for the past 3 months, documenting photos on flickr and posting all the PCB layouts / code on github. Right now the secondary is a bit big compared to many QCW builds (12" tall), but I intend for the coil to be small eventually, so I called the project cute-qcw. The end goal is a compact version of the coil to mount on the front of a bicycle for Burning Man.

I had first light earlier this week and I ramped the coil up to full power for the first time earlier today.

Now that everything works I figured its time to share the project.

The secondary is 12" tall and I am running at the upper pole of ~390KHz, with the secondary tuned above the primary. This puts the gain of the lower pole higher than the upper pole, which can make it difficult to drive with a direct feedback controller. My driver uses a digital PLL and forces ~20 RF cycles at a fixed frequency at the start of the burst to lock on to the upper pole.

Here is a photo to catch your attention:


Github repo is here: https://github.com/westonb/cute-qcw
More photos here: https://www.flickr.com/photos/63341195@N08/sets/72157678478822788/with/47390843571/

I am going to be documenting everything a bit better on github in the next few weeks. Please ask questions if you have any.


5
So this controller regulates the average tank current by skipping pulses? Is this for QCW operation?

Do you have any photos or waveforms of the controller in operation? In the past, people have talked about using a pulse skipping controller for QCW coils but the consensus was that loaded Q is too low to effectively regulate the tank current.

I see a crystal oscillator on the board, are you using the FPGA to control the phase lag digitally to get more accurate zero voltage switching?

Pages: [1]

* Recent Topics and Posts

post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 02:51:26 PM
post Re: What is the true in tuning guide?
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 02:48:02 PM
post Re: A problem solved with hand tools
[General chatting]
Mads Barnkob
Today at 01:48:08 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 01:45:00 PM
post Re: A problem solved with hand tools
[General chatting]
Hydron
Today at 11:21:29 AM
post What is the true in tuning guide?
[Dual Resonant Solid State Tesla coils]
VNTC
Today at 10:01:21 AM
post A problem solved with hand tools
[General chatting]
klugesmith
Today at 07:52:41 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General chatting]
klugesmith
Today at 07:33:30 AM
post Re: tesla coil varnish is dumb
[Solid state Tesla coils]
Hydron
July 14, 2019, 10:49:03 PM
post Re: tesla coil varnish is dumb
[Solid state Tesla coils]
T3sl4co1l
July 14, 2019, 09:59:40 PM
post Re: tesla coil varnish is dumb
[Solid state Tesla coils]
Mads Barnkob
July 14, 2019, 08:20:52 PM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
Netzpfuscher
July 14, 2019, 06:06:30 PM
post tesla coil varnish is dumb
[Solid state Tesla coils]
Fumeaux
July 14, 2019, 05:29:10 PM
post Led Closeups with Mobile phone and lens .
[Smart phones]
DashApple
July 14, 2019, 03:00:09 PM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 14, 2019, 02:06:26 PM
post Re: DRSSTC in brust mode
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 14, 2019, 02:04:22 PM
post Re: Twin System Build
[Dual Resonant Solid State Tesla coils]
oneKone
July 14, 2019, 01:27:18 AM
post Re: DRSSTC in brust mode
[Dual Resonant Solid State Tesla coils]
johnf
July 14, 2019, 01:22:15 AM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
oneKone
July 13, 2019, 03:48:54 PM
post DRSSTC in brust mode
[Dual Resonant Solid State Tesla coils]
SAMGO
July 13, 2019, 04:17:55 AM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
donnersm
July 12, 2019, 08:54:54 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
profdc9
July 12, 2019, 07:16:40 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
profdc9
July 12, 2019, 06:33:00 PM
post Smooth corona or heavy spark, RF wave radiation frequency of Tesla coil drops ve
[Dual Resonant Solid State Tesla coils]
VNTC
July 12, 2019, 11:09:28 AM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 12, 2019, 09:56:38 AM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
oneKone
July 12, 2019, 01:23:58 AM
post Re: Completed my pulsed power generator
[Capacitor banks]
MRMILSTAR
July 11, 2019, 05:48:27 PM
post Re: Completed my pulsed power generator
[Capacitor banks]
Mads Barnkob
July 11, 2019, 02:58:13 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 11, 2019, 02:45:24 PM
post Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
donnersm
July 11, 2019, 06:59:01 AM
post Completed my pulsed power generator
[Capacitor banks]
MRMILSTAR
July 11, 2019, 05:43:31 AM
post Re: Twin System Build
[Dual Resonant Solid State Tesla coils]
fnordest
July 11, 2019, 01:05:42 AM
post Re: "LightningStorm" VTTC project
[Vacuum tube Tesla coils]
Avenger
July 09, 2019, 07:31:37 PM
post Re: Siemens Polyphos 30 xray machine
[X-ray]
oneKone
July 09, 2019, 04:48:29 PM
post Re: Siemens Polyphos 30 xray machine
[X-ray]
Mads Barnkob
July 09, 2019, 03:53:37 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
Bert911
July 09, 2019, 08:45:17 AM
post DRSSTC schematic for simulating (primary feedback self-oscillating)
[Dual Resonant Solid State Tesla coils]
VNTC
July 09, 2019, 06:10:12 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
July 08, 2019, 09:13:42 PM
post Re: Driving the LED lights with the streamers
[Dual Resonant Solid State Tesla coils]
johnf
July 08, 2019, 09:02:20 PM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
oneKone
July 08, 2019, 03:57:17 PM
post Re: Driving the LED lights with the streamers
[Dual Resonant Solid State Tesla coils]
Fumeaux
July 08, 2019, 12:05:54 PM
post Driving the LED lights with the streamers
[Dual Resonant Solid State Tesla coils]
donnersm
July 08, 2019, 11:04:00 AM
post Re: Aliexpress cheap CM300-24H
[Dual Resonant Solid State Tesla coils]
SAMGO
July 08, 2019, 10:43:33 AM
post Re: Hydron's 160mm DRSSTC and topload current measurements
[Dual Resonant Solid State Tesla coils]
Uspring
July 08, 2019, 09:59:49 AM
post Re: Aliexpress cheap CM300-24H
[Dual Resonant Solid State Tesla coils]
oneKone
July 08, 2019, 08:04:44 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
Mads Barnkob
July 07, 2019, 08:19:33 PM
post Re: Twin System Build
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 07, 2019, 08:03:59 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
July 07, 2019, 05:28:04 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
July 07, 2019, 05:24:20 AM
post Re: Induction Heater schematic modification
[Electronic circuits]
johnf
July 07, 2019, 04:53:29 AM