Comparison of Silicon and GaN Transistors Leads to an Optimized Inverter Design
By re-designing IGBT and MOSFET solutions with GaN-based FETs, DRS optimized vehicle inverter performance, increased switching frequency by a factor of four, reduced size and weight, while achieving 98.5% efficiency.
By Scott Ramsay, Technical Director, DRS – Consolidated Controls, Inc.
At DRS, we set a goal to design an improved generation of our 2kVI
vehicle inverter. During our development process we compared the
performance of silicon-based IGBT and MOSFET solutions versus the
recent emergence of normally-off, E-HEMT GaN devices. This paper
describes how GaN devices allowed us to alter our design approach
with the result of increasing switching frequency by a factor of four
and the added advantage of producing significantly smaller inductors.
We were also able to deliver 98.5% efficiency over a wide operating
range, enabling us to reduce the overall cooling system. In the end,
for the same cost, we were able to deliver a significantly smaller and
lighter unit with higher efficiency than ever.
Topologies
Two common inverter topologies were considered, Dual Buck and
Full Bridge. Figure 1 demonstrates a Dual Buck Inverter topology with
silicon-based MOSFETs and SiC diodes, while Figure 2 demonstrates
a standard Full Bridge Inverter with GaN devices…
