Silicon Carbide devices

[schmitt trigger]

Just out of curiosity;
Have you actually employed SiC devices in a product which is currently produced and sold.
In other words, not prototypes or single use lab apparatus?

Even though SiC holds lots of performance advantages, I’ve not seen mainstream implementation.... or am I wrong?

 

[dick_freebird]

I have not. They (SiC MOSFETs) are pretty "needy"
for gate drive (like +20 / -5V) and there's a lot
of "stuff" out there about being real careful about
layout inductance etc. I think eGaN is taking all
the easy consumer applications and SiC gets
the stuff like traction motor inverters, which are
mostly out of the public eye (maybe a lot to do
with the marketing chops, between the two camps
GaN sure has more press coverage).

Due to cost and ease of drive, I'd try GaN first for
any project of mine and only go SiC if I kept
burning devices.

But that's all pretty far from the frame of your
question. Just another perspective from
somebody who reads the news.

 

[Easy peasy]

We use them in a 230Vac to 54V 30A supply for power stations - 1200V low milli-ohms, +18V / -4Vgate drive - they work well

 

[FvM]

We use it in a three phase 400V 12 kW active front end and LLC converter, in production since 2015.

 

[treez]

I saw SiC used in a down-hole(180degc ambient) 300W power supply. dual buck converter for 300v to 24v.
So it must be pretty rugged.
Having said that, those power supplies only have to work for 36 hours or so...until the "mole-bot" has got down and sent up the data, then its just left to rot.
I cant really imagine a 800w+, 240vac boost pfc without SiC...unless it has one of those active snubbers which dips the gate voltage as the rev recovery spike flashes past.

I detect people are nervous about sic though, as it isnt so good with surge currents, and very high dv/dt's.
So short circuit protection might be interesting. When i say "detect" , i mean an engineering manager was asking me about using sic in CCM pfc, as if expecting me to have some horror stories about it....it was almost as if he was bracing himself.

 

[Easy peasy]

SiC diodes are great in CCM boosters, even better with 1200V SiC mosfet too

 

[treez]

SiC diodes are great in CCM boosters, even better with 1200V SiC mosfet too

Do you mean the CCM Boost PFC FET should/would be 1200v SiC?

 

[schmitt trigger]

Thanks for all the replies.

I have read similar things to all the replies.
SiC really makes sense in either high power/ high temperature applications or applications where hard switching the semiconductor would require a significant snubber. Like a high power CCM boost converter.

I have not had the opportunity to work on such a device yet.

 

[Easy peasy]

@ Treez, we have seen Si diodes used in very hard switching boosters to 4kW, single diode IXYS 600V 30A, 230Vac in 420VDC out ...

DSEI30-06A

 

[mtwieg]

SiC diodes are becoming quite common, as they can often be drop-in replacements for Si diodes. Not many "gotchas" to worry about.

SiC transistors are definitely less common. Perhaps their adoption has been slowed due to 600V GaN devices entering the picture, making part selection even more complicated. I always assumed SiC would be more forgiving wrt gate drive than GaN though.