GDT calculation spreadsheet and more information: kaizerpowerelectronics.dk/teslacoils/igbt-gate-drive-transformer-gdt-design-construction-and-test/ Corrections to video: 2:41 Currents and peak currents are not charging currents, but magnetizing current. Charging power is from the driving circuitry and depends on transformer ratio. @drobotk At 12:20 I think you meant E2 is negative and C1 is positive ;)
Half turns are only possible with E type cores. I think we can count the number wires on the inside of the toroid to guarantee the right number of turns.
Interesting topic really! I just quickly googled half turn effect power transformers and apparently that is a bigger issue with high losses than I imagined. This further brings up a ring core as recommended GDT core, compared to E cores. E cores require some different compensating windings to negate half turn influence, if you exit the winding windows on opposite sides.
That is from my "Getting started with the UD3" video series. I did 2 parts so far, last part will be making actual lightning :) Part 2 with a MIDI playing on a static load in the last part: th-cam.com/video/O7194nPNThk/w-d-xo.html
Would it be necessary to use gate resistors or diodes on the secondary of the GDT? Or Zener diodes? I've been using a bootstrap circuit to drive some smaller discrete IGBTs in TO-247 packaging and keep blowing them up, trying a GDT next. Cheers for the video!
Gate resistors is mandatory. You want to switch your current as fast as slowly possible. Meaning that going too fast just gives you overshoot and ringning, too slow gives you higher losses from linear region and getting it just right with a small bump... perfect. Diodes and possible a lower value resistor can be used for faster turn-off.
@@KaizerPowerElectronicsDk So true! Moreover, the ringing is not the only problem here. The IGBT\FET crystal in fact consists of many many small transistors in parallel. Their specs are almost equial, but still have minor variabilities. With no gate resistor, the fastest cell will turns on alone, take all of that current solo and die. Next time - the next fastest cell dies - and so on. Without gate resistor at all, and with notable power, the IGBT\FET chip will degradate and failure with time (days? weeks?). The gate resistor slows down the cells inside, and helps them work together. Another problem - if the IGBT\FET turns off too fast, it can be killed by overvoltage, especially at short cirquit, when the overcurrent protection tries to turn it off, but the SC current is so high that even snubbers ain't enough to handle with the voltage spike created by dU\dt !
Hello sir🙋♂️ Can an old computer SMPS ferrite core be used as a GDT section in an SSTC Tesla coil? Please reply sir my sstc coil work in pending problem GDT core Waiting for your help
Why is a GDT necessary? I'm pretty familiar with the inverter drives that use those IGBT modules (very common in CNC spindle drives) - they don't use transformer drives, they typically use hybrid modules that just contain a strong FET as far as I know to drive the IGBT gates, but maybe there's some secret sauce to the hybrids, as they're always potted to make it more difficult to see what they did in there
Galvanic isolation between driving circuit and power electronics. What you are talking about is a HSD or High Side Driver. Here the isolation is at the logic level and a isolated power supply and driving circuit is floated at the IGBT voltage level instead. I listed Pros and Cons in the article on my website: kaizerpowerelectronics.dk/teslacoils/igbt-gate-drive-transformer-gdt-design-construction-and-test/
It's sometimes useful to galvanically isolate the driver from the high voltage rails, bootstrap and optoisolators are alright, but GDTs are great. Transformers are typically more expensive than solid state alternative, which as far as I'm aware is the main reason they're less common recently. They do also have issues with things like DC switching, as cores saturate with lower frequencies, though in turn saturation can act as a safety mechanism when driving purely inductive loads.
@@UniCrafter Ultimately a GDT pretty much sets in stone how you have to run the IGBT. It's very application specific and doesn't allow for on-the-fly modifications. Whereas, with the same toroid, you could make a really basic SMPS circuit with 4 secondaries, and use simple opto-isolated gate drivers. Allows you full control of the IGBT without having to play around with a transformer every time you want to switch differently or use a different IGBT with different gate charges. Pretty much all EV/hybrid car inverters do it that way, just have a couple SMPS's that take 12v and make their +- 15v or whatever they want to use, and opto-isolate everything. Maybe its just cost but from an engineering perspective, it's possible that they would change the switching frequency on the fly for some reason, IE in sharp acceleration where one may not care about motor noise vs slow acceleration where a 10khz whine would get annoying really quick.
GDT calculation spreadsheet and more information: kaizerpowerelectronics.dk/teslacoils/igbt-gate-drive-transformer-gdt-design-construction-and-test/
Corrections to video:
2:41 Currents and peak currents are not charging currents, but magnetizing current. Charging power is from the driving circuitry and depends on transformer ratio.
@drobotk At 12:20 I think you meant E2 is negative and C1 is positive ;)
This is very informative, especially for the beginner folks! Thank you so much for sharing this.
Thank you :) I put this topic in my video-to-do-list back in 2018, only took 6 years to finish!
Wow, fantastic! Thanks for doing this!
I am happy that you find it useful :)
Half turns are only possible with E type cores. I think we can count the number wires on the inside of the toroid to guarantee the right number of turns.
Interesting topic really! I just quickly googled half turn effect power transformers and apparently that is a bigger issue with high losses than I imagined. This further brings up a ring core as recommended GDT core, compared to E cores. E cores require some different compensating windings to negate half turn influence, if you exit the winding windows on opposite sides.
Great video
Glad you enjoyed it
At 12:20 I think you meant E2 is negative and C1 is positive ;)
Good catch! It is as you say :)
Great video thanks! I'm curious what's going on with the UD3 there, another tesla coil build?
That is from my "Getting started with the UD3" video series. I did 2 parts so far, last part will be making actual lightning :) Part 2 with a MIDI playing on a static load in the last part: th-cam.com/video/O7194nPNThk/w-d-xo.html
Would it be necessary to use gate resistors or diodes on the secondary of the GDT? Or Zener diodes? I've been using a bootstrap circuit to drive some smaller discrete IGBTs in TO-247 packaging and keep blowing them up, trying a GDT next. Cheers for the video!
Gate resistors is mandatory. You want to switch your current as fast as slowly possible. Meaning that going too fast just gives you overshoot and ringning, too slow gives you higher losses from linear region and getting it just right with a small bump... perfect. Diodes and possible a lower value resistor can be used for faster turn-off.
@@KaizerPowerElectronicsDk So true! Moreover, the ringing is not the only problem here. The IGBT\FET crystal in fact consists of many many small transistors in parallel. Their specs are almost equial, but still have minor variabilities. With no gate resistor, the fastest cell will turns on alone, take all of that current solo and die. Next time - the next fastest cell dies - and so on. Without gate resistor at all, and with notable power, the IGBT\FET chip will degradate and failure with time (days? weeks?).
The gate resistor slows down the cells inside, and helps them work together.
Another problem - if the IGBT\FET turns off too fast, it can be killed by overvoltage, especially at short cirquit, when the overcurrent protection tries to turn it off, but the SC current is so high that even snubbers ain't enough to handle with the voltage spike created by dU\dt !
Hello sir🙋♂️
Can an old computer SMPS ferrite core be used as a GDT section in an SSTC Tesla coil?
Please reply sir my sstc coil work in pending problem GDT core
Waiting for your help
The powdered cores from the power section of a SMPS can NOT be used for a GDT.
Why is a GDT necessary? I'm pretty familiar with the inverter drives that use those IGBT modules (very common in CNC spindle drives) - they don't use transformer drives, they typically use hybrid modules that just contain a strong FET as far as I know to drive the IGBT gates, but maybe there's some secret sauce to the hybrids, as they're always potted to make it more difficult to see what they did in there
Galvanic isolation between driving circuit and power electronics. What you are talking about is a HSD or High Side Driver. Here the isolation is at the logic level and a isolated power supply and driving circuit is floated at the IGBT voltage level instead. I listed Pros and Cons in the article on my website: kaizerpowerelectronics.dk/teslacoils/igbt-gate-drive-transformer-gdt-design-construction-and-test/
It's sometimes useful to galvanically isolate the driver from the high voltage rails, bootstrap and optoisolators are alright, but GDTs are great. Transformers are typically more expensive than solid state alternative, which as far as I'm aware is the main reason they're less common recently. They do also have issues with things like DC switching, as cores saturate with lower frequencies, though in turn saturation can act as a safety mechanism when driving purely inductive loads.
@@UniCrafter Ultimately a GDT pretty much sets in stone how you have to run the IGBT. It's very application specific and doesn't allow for on-the-fly modifications. Whereas, with the same toroid, you could make a really basic SMPS circuit with 4 secondaries, and use simple opto-isolated gate drivers. Allows you full control of the IGBT without having to play around with a transformer every time you want to switch differently or use a different IGBT with different gate charges.
Pretty much all EV/hybrid car inverters do it that way, just have a couple SMPS's that take 12v and make their +- 15v or whatever they want to use, and opto-isolate everything. Maybe its just cost but from an engineering perspective, it's possible that they would change the switching frequency on the fly for some reason, IE in sharp acceleration where one may not care about motor noise vs slow acceleration where a 10khz whine would get annoying really quick.