0
\$\begingroup\$

I have a project in which I need a controllable high voltage (400+ V) high current (10+ kA) pulse (from μs to ms.)

Obviously FETs won't cut it because the high voltage will destroy the channel of any FET with such high current rating.

IGBTs are the obvious choice but they are prohibitively expensive.

SCRs are cheap and can take a lot of punishment, but once triggered it won't open until the channel current drops.

Question:

Is there any alternative or methods to shutdown an SCR while a large current it passing through its channel?

\$\endgroup\$
6
  • 2
    \$\begingroup\$ For a speciality see GTO. \$\endgroup\$
    – greybeard
    Commented Apr 8 at 6:32
  • 1
    \$\begingroup\$ Why will HV burn the channel of a MOSFET? \$\endgroup\$
    – Andy aka
    Commented Apr 8 at 9:09
  • \$\begingroup\$ @Andyaka because high-current (compared with SCR and IGBT) FET has rather low channel breakdown voltage. \$\endgroup\$
    – 7E10FC9A
    Commented May 7 at 3:13
  • \$\begingroup\$ @7E10FC9A You can get Silicon Carbide FETs that are rated for such voltages. 400V is on the lower side of what FETs can do. Silicon carbide FETs are commonly found at up to 1200V ratings. GaN might be able to do 650 depending on where you get it. At thousands of amps however, it is nonsensical to use FETs as the heating will be astronomical and uneven. \$\endgroup\$
    – theph
    Commented May 7 at 4:02
  • \$\begingroup\$ At 1mOhm (by paralleling like 6 of these: digikey.com/en/products/detail/infineon-technologies/…) 10kA makes 100kW of instantaneous heating (over a fraction of a second). With a 3.5V diode drop from an IGBT or GTO, it makes 35kW of heat. What you have on your hands is an expensive problem. \$\endgroup\$
    – theph
    Commented May 7 at 4:05

1 Answer 1

Reset to default
2
\$\begingroup\$

You can use an external circuit to force commutate the current to zero, turning your SCR off. Given the cost of it, you'll be better off with an IGBT or possibly GTO.

enter image description here

Source: https://circuitdigest.com/tutorial/thyristor-commutation-technique

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.