IEEE Electrification - March 2022 - 4

FROM THE EDITOR
that Prof. Gross was indeed a giant of
power engineering and a devoted educator.
He initiated two power engineering
programs (at the Illinois Institute of
Technology and Rensselaer Polytechnic
Institute) in the United States after
he moved here from Europe in 1939.
Until then, the 1950 article led to not
only technical details, but also stories
from the past. For more information
about Prof. Eric T. Gross, please visit
this website from the U.S. National
Academy of Engineering: https://www.
nae.edu/29287/Dr-Eric-T-Gross.
Current Articles (What's Popular)
The second example is from reading
articles by Lennart Harnefors. Harnefors
started working on high-voltage
dc and power electronics long ago and
is currently with ABB. Today, with the
increasingly higher penetrations of
inverter-based resources, articles on
the dynamics and stability of gridintegrated
inverters keep popping up.
Harnefors' articles on this topic can be
traced back to 2007. On 23 March 2021,
Harnefors delivered a webinar reviewing
his work in this area: " Robust Control
of Grid-Connected Converters: A
15-Year Evolutionary Timeline. "
The first impression I got from
Harnefors' 2007 article, " Input-Admittance
Calculation and Shaping for
Controlled Voltage-Source Converters "
(Harnefors et al. 2007), is that it is quite
mathematical. Yet it is very relevant
mathematics. This article is the first of
its kind that includes the effect of a
phase-locked loop in impedance modeling.
The approach is quite different
from that of the power system dynamics
community, where we like to build
a big model and pay attention to its
simulation speed. In terms of analysis,
we use numerical perturbation and
Jacobian linearization to extract the
linear models and use modal analysis
to examine influencing factors on
dynamics. This method has been well
documented in Prabha Kundur's classic
book, Power System Stability and
Control (Kundur 1994).
Harnefors' approach is completely
different from our top-down approach.
His is a bottom-up approach. Each
block is examined for its linear model.
Afterward, integration. Furthermore,
Harnefors applies transfer functions
for analysis in various frames with
quite a fluency. For example, the
Laplace transform variable s in a static
frame is directly replaced by s + jω in a
rotating frame, and frequency-domain
responses are examined extensively to
acquire insights. Such techniques are
quite new, and learning them benefits
our research.
Moving Forward
As the readers can see, we are living in
an exciting time with many new technologies
emerging and numerous
mature and classic technologies available
for our use. Learning from our peers
and from our predecessors can greatly
improve our research. So, if you have
learned a good deal from articles, books,
or webinars and would like to share
your perspectives with other readers,
please contribute to the new columns.
Enjoy this issue. Stay healthy. See
you soon.
For Further Reading
L. Harnefors, M. Bongiorno, and S. Lundberg,
" Input-admittance calculation and
shaping for controlled voltage-source
converters, " IEEE Trans. Ind. Electr., vol. 54,
no. 6, pp. 3323-3334, 2007, doi: 10.1109/TIE.
2007.904022.
P. Kundur, Power System Stability and
Control. New York, NY, USA: McGrawHill,
1994.
P. C. Krause, O. Wasynczuk, S. D.
Sudhoff, and S. D. Pekarek, Analysis of
Electric Machinery and Drive Systems, vol.
75. Hoboken, NJ, USA: Wiley, 2013.
H. L. Garbarino and E. T. B. Gross,
" The Goerges phenomenon-induction
motors with unbalanced rotor impedances, "
Trans. Amer. Inst. Elect. Eng., vol. 69,
no. 2, pp. 1569-1575, Jan. 1950, doi:
10.1109/T-AIEE.1950.5060337.
We want
to hear
from you!
Do you like what you're reading?
Your feedback is important.
Let us know-send the editor-in-chief an e-mail!
4
IEEE Electrification Magazine / MARCH 2022
IMAGE LICENSED BY GRAPHIC STOCK
http://www.nae.edu/29287/Dr-Eric-T-Gross http://www.nae.edu/29287/Dr-Eric-T-Gross
IEEE Electrification - March 2022

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