SCR & IGBT

[zacky]

SCR, once it turns on ,then we are forced to use cmmutating capacitors and dc reactors to turn it off.
I am wondering , why IGBT's are not used instead of SCR's and to get rid of the commutating components ?
Is there any advantage of using SCR's instead of IGBJT's for high current applications?

Thanks in advance.

 

[itsmoked]

IGBTs are so expensive that often the other added stuff still puts the SCR solution cheaper.

 

[Skogsgurra]

IGBTs are used in power applications. Almost all frequency inverters use them. There are applications in the 10 megawatts range - thrusters for ships for instance.

SCRs are mainly used in DC drives and mains commutated rectifiers where commutation components are not necessary. There are also CSI inverters with SCRs in them. The switching is normally at a low 300 or 360 Hz.

There are also gate turn off thyristors (GTO) that can be turned off via the gate. They need rather high energies to be turned off. But still usable.

The main reason SCRs are used in high-power applications (hundreds to thousands of megawatts in HVDC transmission poles) is that they can be built for higher currents and voltages than IGBTs.

Gunnar Englund

http://www.gke.org

 

[zacky]

Thanks for reply and the nice information provided.
Now if you going to design inverter,say, 120V/20KVA ac output, what would be the best chice for such application:
SCR / CSI / GTO / IGBT

 

[Skogsgurra]

IGBT, no doubt.

Gunnar Englund

http://www.gke.org

 

[zacky]

Skogsgurra, could you please give some idea about IGBT price 200A/600V & 400A/600V

 

[itsmoked]

Zacky if I were building an inverter I would use IGBTs too.

You want prices... Don't ask us look them up!

Go to DIGIKEY.com and in the front page search stick in "IGBT".

They have 22 pages of them the range up to $300 bucks or so but this all depends on the package, current, voltage, speed, etc. etc.

 

[zacky]

Thanks itsmoked, now do you think the ON resistance of the IGBT will be as low as the SCR does ?

 

[itsmoked]

zacky;... You are discussing building an inverter.... This is a serious, tough, rigorous, undertaking. You need to totally understand all this... It will figure heavily in your design so... LOOK IT UP!

 

[Skogsgurra]

Thanks smoked,

You are handling this very well while I was looking in other direction.

How's the heating system, BTW?

Gunnar Englund

http://www.gke.org

 

[itsmoked]

AHHHHhhh

It is soooooOOOoooOOOOooo nice... {never thought I'd use that emoticon}

I do still need some insulation work, the place chills quickly. And I have never seen a gas bill yet... So you will probably hear my whining soon.

Thanks for asking.