題目：Hybrid Electrical Energy Storage Systems
講師：Naehyuck Chang教授（Seoul National University, Korea）
概要： Electrical energy is a high-quality form of energy in the sense
that it can be easily and efficiently converted into other forms of
energy, and furthermore it can be used to control other forms of energy.
Unfortunately, electricity supply and demand are typically not balanced
with each other. Storage of excessive energy and compensation of the
energy shortage can significantly mitigate the over-investment in the
Like memory devices, no single type of electrical energy storage
(EES) element can fulfill all the desirable requirements. Despite active
research on the new EES technologies, it is not likely to have an
ultimate high-efficiency, high- power/energy capacity, low-cost, and
long-cycle life EES element in the near future. We propose an hybrid
electrical energy storage (HEES) system that consists of two or more
heterogeneous EES elements, thereby realizing the advantages of each EES
element while hiding their weaknesses.
Compared with the conventional homogeneous EES systems, HEES
systems provide high output power and energy density as well as high
power conversion efficiency and low self-discharge at a low capital cost.
Cycle efficiency of a HEES system, which is defined as the ratio of
energy which is delivered by the HEES system to the load device to
energy which is supplied by the power source to the HEES system, is one
of the most important factors in determining the overall operational
cost of the system.
We formulate the HEES management problems and project them into
computer memory system design and management. We break the HEES
management problems into charge allocation into different banks of EES
elements, charge replacement (i.e., discharge) from different banks of
EES elements, and charge migration from one bank to another bank of EES
elements. Even a hybrid EES system cannot achieve high cycle efficiency
if their storage banks have a fixed power and voltage rating because the
optimal power capacity and voltage rating varies by the application and
the state of charge (SoC) of the storage bank. Bank reconfiguration
dynamically changes the array structure of an EES bank and maximizes the
In this talk, we start from introduction to the concept of HEES
systems including EES element characteristics and power converter
characteristics. The main body of this talk is charge allocation,
migration, optimization, and bank reconfiguration. The HEES research is
recently brought up, and thus there are a lot of important open problems.
We will conclude this talk with remarks on the future work.
略歴： Naehyuck Chang is a Full Professor in Dept. of Electrical
Engineering and Computer Science, Seoul National University, Korea. He
was a Visiting Associate Professor at Arizona State University in 2005,
and a Visiting Professor at University of Southern California in
2009-2010. He serves (and served) as Technical Program Committee of
major EDA and embedded systems conferences and symposia including DAC,
ICCAD, ISLPED, DATE, ASP-DAC, GLS-VLSI, ISQED, PATMOS, ESTIMedia, ICCD,
and so on. He served as the TPC Co-Chair of RTCSA in 2007, ISLPED in
2009, and ESTIMedia in 2009 and 2010. He was Vice GC of ISLPED 2010 and
is General Co-Chair of ISLPED 2011. He is also General Chair of
ESTIMedia in 2011. He will serve as a TPC Co-Chair of CODES+ISSS 2012.
He is an Associate Editor of IEEE TCAD and ACM TODAES, and editorial
board members of JOLPE and JEC. He is a guest editor of ACM TODAES in
2011 and TECS for low-power design and embedded multi-media systems in
2010 and 2011. He also serves as the Chair of ACM SIGDA Low-Power
Technical Committee, ASP-DAC SIGDA Representative and ACM SIGDA
Executive Committee (Technical Activity Chair). He is a Senior Member of
ACM and IEEE.