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Development of a Modular High-Power Converter System for Battery Energy Storage Systems
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| Author(s) |
Stephan THOMAS, Marco STIENEKER, Rik W. DE DONCKER |
| Abstract |
The integration of storage systems into the grid is becoming increasingly important due to thegrowing amount of volatile power sources. This paper shows how to design a modular batteryenergy storage system (BESS) for medium voltage grids. Typically, this system is scalable inpower rated from 5 MW up to 100 MW with a storage capacity of several hours. Using powerelectronic building blocks (PEBBs) a converter for dc grids and ac grids can be built. In thispaper, the chosen topology for the ac solution is the cascaded cell converter. The focus isto determine the optimum number of levels, the modulation technique to avoid microcycles ofthe batteries and to present the efficiency. A formula to calculate the parasitic capacitance oflead-acid batteries is shown and verified by measurements, which is important for the design ofsuch a converter system. Moreover, a new charging strategy for LiFePO4 - the chosen batterytechnology for the proposed storage system - is introduced, which prolongs the battery’s life,reduces the charging time and decreases the life cycle cost. The proposed charging strategy andbattery technology compared to lead-acid batteries is also economically evaluated. |
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| Filename: | 0211-epe2011-full-16272470.pdf |
| Filesize: | 432.1 KB |
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| Type |
Members Only |
| Date |
Last modified 2012-01-26 by System |
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