IEEE Power Electronics Magazine - September 2021 - 58

energy production of about 6.5% of the total U.S. national
potential and yet 14% of households on native American reservations
have no access to electricity, according to the
Energy Information Administration. Greeting the attendees
in the native Navajo language, Dr. Atcitty presented
a background on native American energy sovereignty
and provided examples of current DOE energy storage program
projects in tribal lands.
The last two plenary talks were presented on Wednesday
16 June. Prof. Charles R. Sullivan of Thayer School
of Engineering at Dartmouth, Hanover, New Hampshire,
USA, and director at NSF Power Management Integration
Center, gave an exciting talk on the present and future
of magnetics and other power passives. While Dr. Heike
Riel, an IBM Fellow and department head of science and
technology, IBM Research, presented an enlightening
talk on " Quantum Computing- The New Computing
Paradigm. " With advances in semiconductor switch technology,
higher frequencies are becoming practical but
magnetics is limiting the performance. Prof. Sullivan's
talk discussed ways to overcome these limitations by
proposing high-Q resonators, such as piezoelectric, that
can replace conventional resonators built with discrete
inductors and capacitors (Figure 2).
His presentation indicated that commercial lead zirconate
titanate (PZT) based piezoelectric resonator can
achieve power density of up to 100 W/cm3 with efficiencies
from 93% to 99%. By comparison, the keynote showed that
PZT's energy storage capability is comparable to the best
ferrite magnetic cores operating at 1 MHz or higher. However,
Prof. Sullivan's talk suggested that lithium niobate is
a better material and can surpass PZT in performance. To
support his statement, he demonstrated a prototype operating
at 6.8 MHz, and offering 98% component efficiency
Drain
Slew
Rate
RDRV
IN
VDD
VNEG
LDO5V
TEMP
FAULT
OC
LDO,
BB
OCP, SCP, Current
OTP, UVLO
Direct-Drive
Source
GaN
with power density of 148 W/cm3. In summary, he said
that piezo resonators are excellent passive energy storage
components that scale well, but much work is needed.
Likewise, LC resonant structures can also offer high performance
and scale well to larger sizes. Furthermore,
Prof. Sullivan proposed a multilayer self-resonant structure
(MSRS) using thin aluminum foil. Offering very
high-Q with minimal skin and proximity effects, this
MSRS resonator was also implemented in a CMOS chip,
operating at 48 MHz and 0.87 W with 86% peak efficiency.
This effort is a joint collaboration with researchers at MIT,
stated Prof. Sullivan.
RAP, Technical and Industry Sessions
The three RAP sessions offered interesting discussion on
topics such as " Distributed versus. centralized control for
microgrid and nanogrid, " " Does high level of integration
make power converters more reliable or not? " and " Where
does the expertise for the next generation of magnetics
come from? The Magnetics companies or the engineer
designing the power supply? Chaired by Dave Maliniak of
Evaluation Engineering, the panelists for the session on distributed
versus centralized control of microgrid and
nanogrid was a good mix of experts from the industry and
academia. The general consensus at the end of the session
favored distributed control. The second RAP session on the
16th morning focused on whether high level of integration
makes power converters more reliable or not? This session
was chaired by Indumini Ranmuthu of Texas Instruments,
and panelists included Robert Pilawa-Podgurski ((University
of California, Berkeley), Madhu Chinthavali (Oakridge
National Labs), Sandeep Bahl (Texas Instruments), Huai
Wang (Aalborg University), Babak Fahimi (University of
Texas Dallas), and Francesco Carobolante (IoTissimo). Many
Source
FIG 3 Automotive qualified 650 V GaN FET with integrated
driver, protection and active power management.
Source: Texas Instruments.
58 IEEE POWER ELECTRONICS MAGAZINE z September 2021
FIG 4 EPC's first rad hard eGaN FET comes in passivated die form.
IEEE Power Electronics Magazine - September 2021

Table of Contents for the Digital Edition of IEEE Power Electronics Magazine - September 2021
