TY - GEN
T1 - Charge migration efficiency optimization in hybrid electrical energy storage (HEES) systems
AU - Wang, Yanzhi
AU - Kim, Younghyun
AU - Xie, Qing
AU - Chang, Naehyuck
AU - Pedram, Massoud
PY - 2011
Y1 - 2011
N2 - Electrical energy is high-quality form of energy, and thus it is beneficial to store the excessive electric energy in the electrical energy storage (EES) rather than converting into a different type of energy. Like memory devices, no single type of 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 HEES system that consists of two or more heterogeneous EES elements, thereby realizing the advantages of each EES element while hiding their weaknesses. The HEES management problems can be broken 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. In spite of the optimal charge allocation and replacement, charge migration is mandatory to leverage the EES system efficiency. This paper is the first paper that formally describes the charge migration efficiency and its optimization. We first define the charge migration architecture and the corresponding charge migration problem. We provide a systematic solution for a single source and single destination charge migration considering the efficiency of the charger and power converter, the rate capacity effect of the storage element, the terminal voltage variation of the storage element as a function of the state of charge (SoC), and so on. Experimental results for an HEES system comprising of banks of batteries and supercapacitors demonstrate a migration efficiency improvement up to 51.3%, for supercapacitor to battery and supercapacitor to supercapacitor charge migration.
AB - Electrical energy is high-quality form of energy, and thus it is beneficial to store the excessive electric energy in the electrical energy storage (EES) rather than converting into a different type of energy. Like memory devices, no single type of 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 HEES system that consists of two or more heterogeneous EES elements, thereby realizing the advantages of each EES element while hiding their weaknesses. The HEES management problems can be broken 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. In spite of the optimal charge allocation and replacement, charge migration is mandatory to leverage the EES system efficiency. This paper is the first paper that formally describes the charge migration efficiency and its optimization. We first define the charge migration architecture and the corresponding charge migration problem. We provide a systematic solution for a single source and single destination charge migration considering the efficiency of the charger and power converter, the rate capacity effect of the storage element, the terminal voltage variation of the storage element as a function of the state of charge (SoC), and so on. Experimental results for an HEES system comprising of banks of batteries and supercapacitors demonstrate a migration efficiency improvement up to 51.3%, for supercapacitor to battery and supercapacitor to supercapacitor charge migration.
KW - charge management
KW - charge migration
KW - hybrid electrical energy storage
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U2 - 10.1109/ISLPED.2011.5993620
DO - 10.1109/ISLPED.2011.5993620
M3 - Conference contribution
AN - SCOPUS:80052706330
SN - 9781612846590
T3 - Proceedings of the International Symposium on Low Power Electronics and Design
SP - 103
EP - 108
BT - IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2011
T2 - 17th IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2011
Y2 - 1 August 2011 through 3 August 2011
ER -