gate drive transformer method

[thedoc298]

I have seen two methods for gdt, one is using 1 ferrite with all 4 outputs. 1 in 4 out. Seen others use two ferrites with 1 in two out. Any advantage with using two cores verses 1 core..? Thanks

[davekni]

Two GDTs is necessary for running pulse-skip mode with drivers such as UD2.9.  If not running pulse-skip mode, there is generally no reason to use two GDTs.  Only slight advantage of two GDTs would be lower leakage inductance IF the single-GDT alternative used only a single primary winding wire.  If the single GDT is wound with four twisted pairs, with one wire of each pair paralleled to form the primary, that is ideal for low leakage inductance.

[thedoc298]

Two GDTs is necessary for running pulse-skip mode with drivers such as UD2.9.  If not running pulse-skip mode, there is generally no reason to use two GDTs.  Only slight advantage of two GDTs would be lower leakage inductance IF the single-GDT alternative used only a single primary winding wire.  If the single GDT is wound with four twisted pairs, with one wire of each pair paralleled to form the primary, that is ideal for low leakage inductance.

Thanks a lot, been looking at different gdt methods for months now. I can't visualize 4 twisted pairs in the manner you spoke, will draw it out on paper, but that is what I will go with. Thanks again for the good info. My brain aint as fresh as 50 years ago. Later on

[Mads Barnkob]

The winding method with a network cable that is described, is how I did in on my first DRSSTC: https://kaizerpowerelectronics.dk/tesla-coils/kaizer-drsstc-i/

[thedoc298]

The winding method with a network cable that is described, is how I did in on my first DRSSTC: https://kaizerpowerelectronics.dk/tesla-coils/kaizer-drsstc-i/

Thanks for the visual. I have watched your videos at least 5 to 10 times a piece. With Alzheimer's its always something different.

[davekni]

The winding method with a network cable that is described, is how I did in on my first DRSSTC: https://kaizerpowerelectronics.dk/tesla-coils/kaizer-drsstc-i/

This is a great finished GDT image.  Very neatly constructed.

I made a little step-by-step tutorial of how to wind such GDTs, using a half-bridge version for simplicity:
https://highvoltageforum.net/index.php?topic=1854.msg13949#msg13949

[thedoc298]

The winding method with a network cable that is described, is how I did in on my first DRSSTC: https://kaizerpowerelectronics.dk/tesla-coils/kaizer-drsstc-i/

This is a great finished GDT image.  Very neatly constructed.

I made a little step-by-step tutorial of how to wind such GDTs, using a half-bridge version for simplicity:
https://highvoltageforum.net/index.php?topic=1854.msg13949#msg13949

Thanks for the link, that is what I needed. And bookmarked

[thedoc298]

The winding method with a network cable that is described, is how I did in on my first DRSSTC: https://kaizerpowerelectronics.dk/tesla-coils/kaizer-drsstc-i/

This is a great finished GDT image.  Very neatly constructed.

I made a little step-by-step tutorial of how to wind such GDTs, using a half-bridge version for simplicity:
https://highvoltageforum.net/index.php?topic=1854.msg13949#msg13949

Thanks for the link, that is what I needed. And bookmarked

Hello again, Dave, just getting down to doing a final wind of my gdt and looked a yours and madds and like the wrap method. One question, on one core only had 4 windings and the other 11 wraps, how should one go about picking a number to wrap.  I was just going to go for about half, but is their any good numbers. I usually make a gdt and test it, by checking the input and output at the frequency of my coil looking for the best response per wrap method and core. This project has went slow for me, found out I have four different cancers and been getting them removed. Little stressed out at times. Thank every one on this site, I always worry that some of you all will disappear from the site before I get mine running. Latter all   

[davekni]

Hello again, Dave, just getting down to doing a final wind of my gdt and looked a yours and madds and like the wrap method. One question, on one core only had 4 windings and the other 11 wraps, how should one go about picking a number to wrap.  I was just going to go for about half, but is their any good numbers. I usually make a gdt and test it, by checking the input and output at the frequency of my coil looking for the best response per wrap method and core.

Most people wind more turns than needed just for margin.  Down side of more turns is higher leakage inductance.  Requires higher gate resistance to avoid excessive overshoot, slowing down Vge rise and fall times.  Down side of too few turns is core saturation, which causes more serious problems.  That's why people error on the high side.  However, if calculated or measured accurately, there is no need for extra turns.

Given your prompting, I just added a GDT turn calculation post to my GDT tutorial thread:
    https://highvoltageforum.net/index.php?topic=1854.msg19355#msg19355
Please let me know if it needs any further clarification.

This project has went slow for me, found out I have four different cancers and been getting them removed. Little stressed out at times. Thank every one on this site, I always worry that some of you all will disappear from the site before I get mine running.

Sorry about your cancer recurrence.  Hope that doesn't repeat.  I'll intend to be around for a while yet.  My thyroid cancer is not too likely to show up again.

[thedoc298]

Hello again, Dave, just getting down to doing a final wind of my gdt and looked a yours and madds and like the wrap method. One question, on one core only had 4 windings and the other 11 wraps, how should one go about picking a number to wrap.  I was just going to go for about half, but is their any good numbers. I usually make a gdt and test it, by checking the input and output at the frequency of my coil looking for the best response per wrap method and core.

Most people wind more turns than needed just for margin.  Down side of more turns is higher leakage inductance.  Requires higher gate resistance to avoid excessive overshoot, slowing down Vge rise and fall times.  Down side of too few turns is core saturation, which causes more serious problems.  That's why people error on the high side.  However, if calculated or measured accurately, there is no need for extra turns.

Given your prompting, I just added a GDT turn calculation post to my GDT tutorial thread:
    https://highvoltageforum.net/index.php?topic=1854.msg19355#msg19355
Please let me know if it needs any further clarification.

This project has went slow for me, found out I have four different cancers and been getting them removed. Little stressed out at times. Thank every one on this site, I always worry that some of you all will disappear from the site before I get mine running.

Sorry about your cancer recurrence.  Hope that doesn't repeat.  I'll intend to be around for a while yet.  My thyroid cancer is not too likely to show up again.

Thanks for all your help, will check out the calculator, I spent all day and night winding, testing, rewinding and more testing. Hope yours stays away. The best thing I bought lately was a amplifyer for my sig generator make a big difference with enough drive to the cores. Later on