TY  - JOUR
A1  - Bragard, Michael
A1  - Soltau, N.
A1  - Thomas, S.
A1  - De Doncker, R. W.
T1  - The balance of renewable sources and user demands in grids : power electronics for modular battery energy storage systems
JF  - IEEE transactions on power electronics
N2  - The continuously growing amount of renewable sources starts compromising the stability of electrical grids. Contradictory to fossil fuel power plants, energy production of wind and photovoltaic (PV) energy is fluctuating. Although predictions have significantly improved, an outage of multi-MW offshore wind farms poses a challenging problem. One solution could be the integration of storage systems in the grid. After a short overview, this paper focuses on two exemplary battery storage systems, including the required power electronics. The grid integration, as well as the optimal usage of volatile energy reserves, is presented for a 5- kW PV system for home application, as well as for a 100- MW medium-voltage system, intended for wind farm usage. The efficiency and cost of topologies are investigated as a key parameter for large-scale integration of renewable power at medium- and low-voltage.
Y1  - 2010
U6  - https://doi.org/10.1109/TPEL.2010.2085455
SN  - 0885-8993
VL  - 25
IS  - 12
SP  - 3049
EP  - 3056
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Köllensperger, P.
A1  - Bragard, Michael
A1  - Plum, T.
A1  - De Doncker, R. W.
T1  - The dual GCT : new high-power device using optimized GCT technology
JF  - IEEE transactions on industry applications
Y1  - 2009
U6  - https://doi.org/10.1109/TIA.2009.2027364
SN  - 0093-9994
VL  - 45
IS  - 5
SP  - 1754
EP  - 1762
ER  - 
TY  - JOUR
A1  - Windmüller, Anna
A1  - Schaps, Kristian
A1  - Zantis, Frederik
A1  - Domgans, Anna
A1  - Taklu, Bereket Woldegbreal
A1  - Yang, Tingting
A1  - Tsai, Chih-Long
A1  - Schierholz, Roland
A1  - Yu, Shicheng
A1  - Kungl, Hans
A1  - Tempel, Hermann
A1  - Dunin-Borkowski, Rafal E.
A1  - Hüning, Felix
A1  - Hwang, Bing Joe
A1  - Eichel, Rüdiger-A.
T1  - Electrochemical activation of LiGaO2: implications for ga-doped garnet solid electrolytes in li-metal batteries
JF  - ACS Applied Materials & Interfaces
N2  - Ga-doped Li7La3Zr2O12 garnet solid electrolytes exhibit the highest Li-ion conductivities among the oxide-type garnet-structured solid electrolytes, but instabilities toward Li metal hamper their practical application. The instabilities have been assigned to direct chemical reactions between LiGaO2 coexisting phases and Li metal by several groups previously. Yet, the understanding of the role of LiGaO2 in the electrochemical cell and its electrochemical properties is still lacking. Here, we are investigating the electrochemical properties of LiGaO2 through electrochemical tests in galvanostatic cells versus Li metal and complementary ex situ studies via confocal Raman microscopy, quantitative phase analysis based on powder X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electron energy loss spectroscopy. The results demonstrate considerable and surprising electrochemical activity, with high reversibility. A three-stage reaction mechanism is derived, including reversible electrochemical reactions that lead to the formation of highly electronically conducting products. The results have considerable implications for the use of Ga-doped Li7La3Zr2O12 electrolytes in all-solid-state Li-metal battery applications and raise the need for advanced materials engineering to realize Ga-doped Li7La3Zr2O12for practical use.
KW  - LiGaO2
KW  - garnet solid electrolyte
KW  - ga-doping
KW  - Li7La3Zr2O12
KW  - solid-state battery
Y1  - 2024
U6  - https://doi.org/10.1021/acsami.4c03729
SN  - 39181–3919
VL  - 16
IS  - 30
PB  - ACS Publications
CY  - Washington, DC
ER  -