Wide Bandgap Semiconductors for Power Electronics – EEs Talk Tech Electrical Engineering Podcast #20

Wide Bandgap Semiconductors for Power Electronics – EEs Talk Tech Electrical Engineering Podcast #20


everybody welcome to another episode of
EEs Talk Tech my name is Mike I am at Daniel Bogdanoff and we have Kenny
Johnson back with us today we’re going to talk about wide bandgap
semiconductors and how they’re used for power electronics so I went to APEC the
applied power electronics conference like three years ago I haven’t been able
to go the last couple years because it’s in the middle of scope month and you
know, scope month, so that’s busy but one of the things that people kept coming up
and saying hey can you measure this like you know 1400 volt yeah you
know like absurdly fast you know switch rate can you measure that and they’re
like well no that’s way too high of a voltage so my understanding is they’re
working with wide bandgap semiconductors yeah yeah you know you kind of stumbled
into it the same way I did was that well not necessarily at APEC but going around
and talking to our users and everything about you know hey so what are your
problems how can we help you and keep getting questions like well you know I
need something that can measure like from zero to a kV at like a gigahertz
bandwidth right thought what the heck is lightning I mean what are you doing and
and so you hear one guy ask about it it’s like okay well this is some
high-energy physics guy or something but but more and more people are asking
about this and so what is this and I’m like oh it’s wide bandgap semiconductors
and I’m like okay tell me more so give us like a you know 30 second to 30
minute overview let you go yeah yeah you guys know me too uh
bit of a talker you know my wife and kids they’ve got a
bit of sign language so that they use on me I gotta tell you this story I know a
couple gestures but I wouldn’t necessarily call them something yeah
okay it’s kind of like that um but basically I was uh I think I was at a
store one time and the clerk was very very helpful and very very talkative and
almost to the point of being bothersome and so after I got done with a guy told
my wife I said that guy was like a booger on your finger you just couldn’t
get rid of I’m he just kept talking and talking and
she’s like now you know what it feels like and so whenever I’m like talking
and she thinks I’m like running over she’ll go stand behind the other person
and makes that like little thing like she’s flicking a
booger it’s okay well I have to say that I’m excited to finally have you on the
podcast because I could just listen to you tell stories like that for hours
yeah you know having having having all the kids we could tell some great
stories we might have to start a whole different podcast you know the Kenny’s
analogies that’s what I’d like to see nice little intro and Kenny walks in
with Mister Rogers sweater and is like today we’re gonna talk about [beep]. yeah yeah
Oh gasp oh that could be fun actually I might have to try that on the side all
right let us know in the comments yeah yeah I feel like one thing we never
really talk about is he our selves so if you care at all I guess let us know no
one cares anyway sorry yes yeah well so you know I started asking these guys
about this and and some of the helpful stuff came from I was actually talking
to this is at some universities where they’re doing that research and
everything and so they start explaining to me they say well what it is is these
wide back and wide bandgap semiconductors specifically gallium
nitride and silicon carbide they’ve got some great features to them the most
prominent one is that they can turn on and off much much faster than
traditional silicon based power semiconductors they also have better
thermal conductivity they don’t heat up as much listed out
exactly exactly so you can put smaller heat sinks or smaller fans or something
like that on it so with that higher switching speed they’re more efficient
they also there’s this characteristic that’s called R-on so when when you
think about it like with a typical switching power supply you know kind of
toggles back and forth voltage current voltage current and ideally when you’re
in the mode where well we’re voltage well that current would be zero or it’s
like well we’re shoving out some current the voltage would be zero well it’s not
really zero right and so and the way they measure that is they call it R-on
and so that the during that phase then the semiconductors have much much lower
resistance then so there’s less severely zero it’s like that it’s a drain source
resistance is that correct I think so I think so yeah and the but the other
thing too is that so then when you think about like the switching is that’s the
time when both you know neither neither quantity voltage or current are actually
zero they’re they’re actually a number there right now and start multiply them
and so if you can make those switch faster faster lads that’s more
efficiency that make sense and and if there’s a slew rate associated with it
the faster it is the lesyk and switching loss exactly it’s a switching loss and
so uh anyways uh and so this uh this first professor I was talking to he’s
showing me this is actually over in Denmark of all places but he was showing
me a they’re working on like a part for a substation and you know like those
huge transformers we have out back in the building so he showed me like here’s
the existing transformer looked like my refrigerator at home is about that big
and he says if we do that same transformer here’s the same transformer
in wide bandgap semiconductors and was about the size of a lunch box oh and I
was like oh my goodness Wow and I was like to ask what are the downsides
because everything so far sounds like it should have been implemented whenever it
was discovered it’s like about everything else when you first when it
first comes out it’s very expensive and so for example if if you think about
like a lot of things out there I might use our scopes as an example we could go
purchase a power supply that is based on wide bandgap semiconductors okay so our
power that would make our scope more energy efficient but those parts are
more expensive does the consumer value that energy efficiency in something like
an oscilloscope yet you know can we charge a premium to recover for that?
yeah maybe maybe not right now it’s worth now what it would cost it exactly
and so it’s at that early phase right now and everything to wear just like
everything else you know once you get a the economies of scale the price comes
down everyone adopt it part of the problem though of
the adoption is those very very fast edge speeds so like we were saying well
we was saying I need a gigahertz you like a gigahertz well they’re just using
that old band width times rise time equals 0.35 kind of thing in saying well
this is the rise time on those things I mean they got a crazy slew rate so I
need a gigahertz well if you start switching things that fast on your
board you have terrible EMI and RFI problems and so it’s a matter of how
you’re gonna package these things in such a way that you can not have
these EMC you you know and and RFI problems that make sense. the other
thing is that they are very because they’re switching so fast is that they
can’t handle much inductance in there sure right yeah and so was in that the
inductance is gonna like not let you change basically exactly exactly yeah
there’s a video on our youtube channel about that yes there you go shameless
plug yeah called debugging parasitic inductance okay cool I’ll go watch it
gotta go yeah so the thing there is they can’t is you can’t have much much much
inductance in the circuit everything and so it isn’t so they don’t necessarily
lend themselves to the existing packaging plus it’s also still early
enough that in fact like a lot of the standards committees like that JEDEC I
think is just now starting to come up with some standards about how you would
specify performance and how you had measure it’s you can compare apples to
apples when you’re looking across things so talking to a couple of guys from the
JEDEC committee and everything it sounds like we’re today with wide
bandgap semiconductors were at the point that like traditional silicon
semiconductors were back in their beginning and everything to where some
of them exist but how do you know which ones good there isn’t really any
packaging standards yet or common footprints and so so it’s one of those
things that kind of like wait and see but the mind-boggling part about this is
that the size and the energy efficiency and like I said that that professor I
was talking to he was working on utilities and the wide bandgap
semiconductors then that’s sort of the gateway to the smart grid you know that
the feature there is it one of the one of the features there beyond the energy
efficiency is when you think about smart grid at least as I understand it is we
start breaking things down into smaller and smaller pieces to where we’re
turning things off when they’re not being used rather than keep them think
everything energized all the time we’re turning it off we can turn it on and a
heartbeat turn it off not like the wall itself either yeah um just so just like
your your phone for example right you know if I’m not using you go to sleep
well they want to go even better than go to sleep it’s like I’m just cutting you
off you get no power and and so uh I think the first place will or will
pricey these shown up might not be utilities but probably is more in
supplies for server farms you know can talk to these folks the single biggest
cost of running a server farm eight the people in ain’t the building and it
isn’t the server’s it’s the utilities oftentimes the locations of server farms
is based on utility prices and there’s a lot of negotiation with local utilities
– yes yeah yeah by far and away the highest expense oh my gosh did you think
about how much so what it’s it’s a pretty significant percentage of the
entire us as power grid goes towards just powering servers well I know the
number is but it’s big well let me put this in perspective I read a an article
now this was seven years ago this was like printed in 2010 I think it was it
was a New York Times article and they were trying to estimate how much power
Google consumes oh and so they kind of estimated at that point in time that
Google use Google watt use 2.3 terawatt hours of electricity now to put that in
perspective um there is a power plant in the center of Colorado Springs that the
highway has to wrap around and it creates traffic nightmares all the time
because they curved the road and that power plant is not big enough to supply that
much power and they also estimated that at that point in time again this was a
long time ago before cloud had taken off but that there was about 900,000 servers
on that Google was running now here’s the shocking point
that was about 1% of the world servers hmm Google’s only 1% of the world
servers yeah with 900,000 servers in 2.3 terawatt hours of electricity and that
was only 1% to the servers in the world and I was like oh my goodness so
you know things have changed a bit since then. In other news google has 1%
of the world servers – and probably Facebook and right at me CIA
yeah exactly so you can see how fast it ramps up and so I think that’s where
we’ll start seeing this stuff first is for because they’re willing to pay for
that the expertise the development you know these companies have the pockets
then to go through and work on the packaging and things like that but it’s
just fascinating you another I think we shared this in one of the other blurbs
while we’re talking was just a bit about how the US Department of Energy thinks
that this is such a big important deal that they want guys like you and me to
go back and get a degree in power electronics right and they’ll pay I
can’t remember how much the stipend was whether it’s like you know a full
fellowship or just cover tuition kind of stuff but and they also think that is
vitally important every country in fact but I think this is to have a solid
manufacturing base for that and everything the cosmic is the future of
power because of this efficiency well and like diplomatically if you control
the fabrication of silicon germanium gallium nitride – silicon
carbide yeah that I if you control the source of you know those fabs then you
basically control – you literally have power over the world right exactly and
so and you think about it too these are also because of their small size in
their efficiency well gosh that’s great for like hybrid electric vehicles or
all-electric vehicles and everything so it’s it’s one of the enabling
technologies for the efficiency of that it’s also very very important for like
the alternative energy sources like a wind and solar for all those inverters
for getting the power onto the grid and everything I imagine you could also
deliver power faster because you’re if you’re working on a kV right like
being able to instead of I’ve converted from wall or something at
a 110 volts or 220 like you could just you know charge the vehicle in a snap
without Oh – that’s conjecture – yeah I don’t know how much of that with the
with the with charging the batteries is limits to existing batteries or how
big a hose you can can pile in there but part of it too is
you know if these things can turn on and off faster and switch faster you can
control them faster they can respond to loads faster and everything and so all
of that then just means you have to have less excess capacity you can more supply
demand on demand rather than have have to have extra extra capacity sitting
around someplace and just a couple
of things off this this little infographic from the US Department of
Energy, so they say that if industrial motor systems so this is the variable
frequency drives for like pumps and things like that you’ll for you know
shoving around the natural gas or you know that the water and our pipes and
all that kind of stuff if if those motor control drives were wide bandgap
semiconductor say is enough for a million homes if the wall warts that we
use for our pcs our smart phones stuff like that if we change those over that’s
1.3 million homes and if the inverters for wind farms that’s seven hundred
thousand homes and so that’s nothing more than just changing or is something
you know just just getting on to the the new product or the new technology do you
remember a couple years back we brought in someone who is you know a pretty
strong oscilloscope user who worked for a company that developed pumps and
electric motors yes and the stat he brought up I don’t remember the
specifics but it was something like 20 plus percent I think it was higher than
this but I want to be conservative was like 20 percent of the world’s power is
consumed by motors yeah yeah I think it was upwards of like 40 percent of the
world’s power but yes yes so we doubled it so I I won’t mention that that the
company’s name but but they are they’re out of Denmark and they’re the the
biggest pump manufacturer over there in Denmark and they’re actually because of
that important for them yeah exactly you know they’re kind of on the leading edge
with you know wind and things like that the renewable energy but of course
because pumps are such a huge consumer of power
and that just gave me away until I started thinking about it like last over
the weekend when I was coming back from from canyoneering out in Utah and
driving across Eastern Utah and western Colorado is all that natural gas out
there well you know you get that out of the ground you got to pressurize it you
got to shove it someplace how about that water when we turn on the faucet and
that’s just that’s just for our utilities and everything I mean when you
think about all the industrial for like oh we’re gonna go make you know
chemicals or paints or whatever else it’s just mind boggling always complain
about how cold this room is you know you walk in the room we film in it’s like oh
it’s cold you know there’s an air conditioner running air conditioner is
based off of a compressor my professors you know that it’s it’s a it’s a pump
the air pump there there is a hole in fact one of our wife and I have three
sons the oldest son works for a company that goes around and helps companies or
customers for them but you know school districts libraries companies like us
recover energy costs by by things just like that where sometimes it’s smart
stuff like okay you know we’re gonna go ahead and we’re gonna go out look at the
forecast tomorrow if it’s going to be hot we’re gonna preach ill everything
with cold air to know understand but the future then is going towards these these
compressors and pumps because these things for example are you know they’re
moving cooling water and things like that around going to these wide bandgap
semiconductors and these in these motor controllers and everything and it’s it’s
the future and the reason I I was excited about it because it seems like
that’s the next place where we can help a lot of people do the things they need
to have done they’re looking for some really exotic tools to measure these
things there really aren’t some good ones yet they’re starting to show up by
the way they’re starting they’re starting to show up but it’s an
opportunity to be helpful and your myself I like to I like to learn and
it’s kind of like if my brain is like the balloon of knowledge if if the
balloon continues to expand I feel enriched if it quits expanding I could
kind of bored and so I was really excited when this starts coming up in
everything because it’s a place to go learn about something new
and help people in industries that we normally don’t help you know myself
working here you know I’m not usually not working with guys that are doing
solar farm inverters or electric rides and stuff like that it’s more that you
know the servers and the smartphones and stuff like that so it’s really it’s
really pretty cool and it’s uh it’s something that there’s jobs there and
it’s gonna drive the economy when it starts to go because it’ll start turning over
the utility grid and so much more awesome so I would ask our listeners and
Watchers if any you guys are power engineers and you have some thoughts on
this please let us know we’d love to read your comments about it I think one
of the things that that when I was at APEC and did a little more digging into
it it turned out that a lot of the people at least three years ago that
we’re looking at this were actually on the power generation side of things yeah
so it makes sense right if you can increase the efficiency of your power
plant you’re gonna make more money because you can deliver more power to
paying customers or to whoever here it’s over in power too so yeah you know and I
think the some of the places that you probably see to start showing up first
is gonna be some of the the large metropolitan areas you know LA New York
stuff like that where sure I think like right here in Colorado you know if
you’re a if you’re a corporation you’re probably negotiating a utility
rate that’s about something like four cents a kilowatt hour with utilities out
in LA it’s probably something like around like 18 cents a kilowatt hour and
so there’s a lot of money to be made or saved there if that’s your motivation or
you know if you’re just trying to you know have a you know be nicer to the
planet and everything there’s there’s a lot of opportunity there and then for
for things like you know whether it’s you know this the size and the form
factor of our products just the fact that these things can be so much smaller
that was nice you know I smaller you know more stuff in a smaller space so if
you’re that if you’re that server form and everything maybe what that means is
you don’t have to change out anything the server farm and also you can have a
lot more computing power in that same size building with that same cooling
capacity and so you know that’s it and with the explosion of the cloud well I
tell you that’s that’s what it’s gonna be so I think utilities and servers is
we’re going to see that stuff showing up first
interesting we have to keep an eye out for it yeah yeah you own as I learn more
but that’s it was just my my new nerd thing I was like oh this is cool
somebody gotta learn about it yeah it’s really cool you mention this because now
that I’m the more I’m thinking about it you’re talking about how motors and
pumps take up most of the power on the planet if you think about it if you
think about any form of work or any form of energy delivery it’s all just bout
moving stuff around whether it’s a refrigerator moving heat in and out
where the light bulb push and electrons around or moving air water around so it
sounds like there’s probably a lot of applications for this that are probably
not as obvious as what we’ve been talking about already so it’ll be cool
to see where it goes what do you think the the life cycle is for this when are
we going to start seeing it implemented gosh that’s a great question you know I
I knew that for a while there so I was digging into this really heavy up until
about six months ago and had to had to move off to something else but I think
we’re probably in about like right now some of those big name companies out
there that you think of for like power semiconductors you can they’ve got parts
right now today and I think it’s gonna start really I think you probably start
seeing in the next two to five years it’s gonna be you know competing with
traditional power semiconductors and this is a lot more mainstream you know
the challenge really right now what I get the biggest the biggest roadblock
right now is that that efficiency is due to how fast you can switch those things
but if you really start switching that fast you just have a radiation nightmare
right here and you’re you know you’re RFI noise is just a super problem and so
trying to and so what guys do it’s like oh let’s turn it down so it’s not
switching as fast well they’re what your efficiency right and that from talking
to people I think is the biggest problem they got right now and so as soon as
somebody kind of figures out the way to package that and do that and really be
successful it’s just gonna blossom everywhere I have a question so is the
noise you know the radiation and I assume it’s both but is it how fast
something that’s not necessarily the speed of the edge but the fact that
they’re doing it like repeatedly over and over and over so if you like you
know switched fast but had a slower frequency and then you’re just liking
suppliers you’re using a better charge storage system, so isn’t it like
left hand rule electromagnetic kind of stuff well well you know so just
going where because the fast edge has those frequency component right exactly
but the power is not that emission is you know if so the fast edge is what
causes the problem many many sequential fast edges builds up that it’s additive
and adds the problem and so with when you go look at like the the requirements
for like you know having your having your part like for us to pass our RFI
certification we can have emission levels at a certain up to a certain
level as acceptable that’s what they do is that’s where you start seeing things
like this spread spectrum clocking sure so you’re varying the frequencies so
you’re making the noise but areas exactly exactly so that’s and and so
with these things the major source of the noise is it’s that lightning strike
adjacent channel power is now this is like lowering the voltage of it like if it
has like the same slew rate but it’s five volts instead of five hundred does
that reduce EMI or because we’re talking about this being at 1400 volts what if
they if they dialed that back with that like if your edge is taller have for
power yeah yeah assuming it does but I don’t know um gosh I don’t know you know
thinking about that you know that the slew rates the same is just you know how
high a hill does it have to climb and everything yeah I don’t know it must
affect the power because if you had a negligibly small like a you know maybe
you’re doing like a microphone up and down it’s not gonna do anything but if
you’re doing yeah like going back to good old calculus take it to infinity and take it to zero, you know if it’s really tiny it’s not doing anything a lightning strike in
the backyard makes a hell of a lot of yeah a lot of you know what the magnetic
interference alright it stupid question time mmm what’s the widest bandgap and
why? I see on your chart here we got diamond at the bottom
can they expect like diamond cell phone soon or wow I you know it’s actually you
know carbon yeah yeah yeah so the widest bandgap yes like you know you can see
the same chart I’m looking at as a – yeah pay attention
yeah so diamond but you know I don’t think we’re too good at making what’s
the diamond band gap is it that have a 5 5.5 electron volts (eV) and gallium
nitride 3.4 eV silicon carbide is 3.3 eV and then
things like typical silicon is 1.1 eV germanium is 0.7 eV okay and you’ll
probably one of the wide bandgap parts that you’re familiar with the most right
now you know some of the wide bandgap semiconductors produce visible lights
and so some of high efficiency LEDs yeah gallium nitride parts would it come dot
something dots I don’t remember I learned about it in school I should know
this – dippin dots yeah light up to that school in the dark
anyway we’re out of time that was yeah we’re right on time so
thanks again Kenny for coming out it’s been great having you for two episodes
in a row I’m sure all if you want you know story time with Kenny will set up
the fireplace yeah then I’ll really answer that wide bandgap question there
was quite a gap this week and I try to cross and didn’t make it that canyon and
and I got some blunt trauma to my right butt cheek that is just amazing so I can
tell you some I knew we had to be peachy or better here so yeah I’m good okay
okay I haven’t had to use the the sensory tool yet heavily not for the
podcast that I’m aware of well maybe that one episode we’re gonna
throw away yeah yeah awesome you through sorry folks
anyway that’s all for today make sure you subscribe to the keysight
oscilloscopes youtube channel and EEs Talk Tech on your favorite podcast engine
give us a review let us know what you think in the comments if there’s topics
you want to cover keep putting them we’d like to read them
thank you for watching we’ll see you next time Cheers take care buddy yeah my car gets broken into all the
time but I leave the outside when I leave it unlocked but I leave nothing in
my car so I’d rather have someone go through my glovebox and break a window
so it’s happened like three times the last couple months and all they take is
like a dollar with the change and I rent a little tray so I think I’m gonna print
a sign up put in my window and says there’s nothing in my car you should
know this by now thank you come again they’re actually very kind about it I go
and I see my door like softly closed and I like close but so the lights don’t
stay oh yeah they don’t want to plan it and exactly no I have my glove boxes my
user’s manual and all my service records and they were just like sitting nicely
on the floor in the passenger side and eyes closed no lights were left on, at least they’re nice about it

10 thoughts on “Wide Bandgap Semiconductors for Power Electronics – EEs Talk Tech Electrical Engineering Podcast #20

  1. We care about you guys but if you limit personal talk to the fun professional setting you already operate in, I'm happy to listen to you guys talk about personal or technical stuff!

  2. I am working on induction motor drive based on SiC devices. Actually, although they are new, they thrive rapidly. When I started the work, just Cree (now, known as wolfspeed) produced this kind of devices ,now, Semikron, Infenion, etc are manufacturing SiC devices. This device will dominate the field of power electronics if the EMI problem gets solved. Can you imagine, we can have 15kV mosfet? even talking about that making me feel excited

  3. I'm almost done with Robotics Engineering and I don't know in what to do a master degree
    I love electronics, Robotics, Microcontrollers, wireless control.
    I recently got into image processing with Microcontrollers, and learning more about making my own encapsulated circuit.
    Can you give me a hint?

  4. It's interesting that you guys mentioned Denmark a couple of times. I am doing my Master degree in Energy Engineering (specializing in Power Electronics) in Denmark.
    You mentioned about data server industry briefly, but I would love if you could tackle these major market areas in separate podcast (data server, EV, renewable energy) focusing on WBG devices.

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