Graphene-on-SiC - ISOM

NEWS ANALYSIS
SiC infiltrates inverter markets
As photovoltaic inverter manufacturers adopt SiC MOSFETs, when
will other industries move towards wide bandgap devices?
aS The PoWeR elecTRonIcS market
embraces a buoyant decade, the
future for wide bandgap devices looks
bright. Sic diodes have stormed into
the photovoltaic inverter market, and
the same flavour of moSFeT is now
penetrating this high-end segment. This
trend looks likely to continue.
Recently, market analyst yole
Développement, predicted the entire
inverter market will swell from
$45 billion in 2012 to $71 billion by
2020. as expected, the market segment
of the moment for the Sic industry
is PV inverters, but as yole analyst
alexandre avron highlights, unexpected
opportunities have surfaced.
“yes, we are seeing PV inverters first,
but what is a little surprising is the use
of Sic [devices] in light rail traction
applications,” he says. “There has been
a real interest for the Sic moSFeT and
several companies are already carrying
out field tests.” as avron highlights,
alstom is testing Sic moSFeTs in its
auxiliary inverters for trains. “many more
small research and development teams
in major businesses, especially in asia,
are pushing for new materials,” he adds.
“This is a traditional, conservative market.
you just don’t expect rail traction to be
attracted to Sic.”
more predictably, avron expects
the equally conservative hybrid and
electric car manufacturers to show a
greater interest in Sic devices. These
components can operate at much higher
temperatures than silicon counterparts,
removing the need for liquid cooling
loops and cutting the size, weight and
volume of the overall inverter system.This
is quite a bonus for the performancedriven
but space-constrained car
manufacturer. But still these players will
first scrutinise how Sic performs in the
solar industry, which as avron puts it, is
providing the “field test”.
“We’ve looked at these photovoltaic
inverters and right now the architecture
hasn’t changed much,” he says.
“manufacturers have taken out the 1200V
silicon IGBTs and put in either a Sic
moSFeT or JFeT, and changed the
input boost converter a little bit. They
will now see how the [device] reacts in
real-life conditions at higher volumes of
production.”
But change is afoot. according to avron,
new inverter architectures − that make
the most of the advantages that Sic
moSFeTs and JFeTs can bring − are
under development. “These have, for
example, higher switching frequencies,
and if you compare the [designs] to
today’s architectures, you really see how
much room for improvement there is.”
avron doesn’t expect the new, improved
inverter architectures will surface for
two to three years yet. “We know [other
industries] will go for these inverters, but
first inverter manufacturers need to see
exactly how Sic reacts.” he adds. “The
moSFeT is really the heart of the inverter
and if your heart isn’t strong then you’ve
wasted your money... but in two to three
years, manufacturers will no longer be
afraid to base a real product on the Sic
moSFeT.” But what about Gan − many
power device manufacturers have touted
progress in high power Gan diodes and
transistors − yet how many products have
reached the market? The long-awaited
arrival of the Sic moSFeT only came
after a long fanfare of announcements,
and avron is concerned Gan transistors
are following the same path.
“We’ve seen lots of marketing about
what companies are doing in-house,
but still we don’t have a 600 V device
available,” he says. “I expect there are
non-disclosure agreements and the
players are getting the first production
batches from Gan manufacturers, but it’s
a little late.”
Still, progress is underway. For example,
california-based Transphorm qualified
its 600V hemT last year and recently
revealed a 600V Gan module for Ganbased
high power PV converters. and
avron reckons industry will adopt these
and future Gan devices.
“We think it will take a little bit of time...
but Sic should be used in very high
voltages and we could then see Gan
used where Sic is now, PV inverters,
electric cars and so on,” he says. “We
are seeing different positioning for Gan
and Sic, and more people are accepting
that there is no full competition between
the two [technologies].”
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24 www.compoundsemiconductor.net April/May 2013