Development of Large-Capacity Converter for Battery Energy Storage Systems

Renewable energy sources may cause the power grid instability due to their output fluctuations. One of the countermeasures to such problems is Battery Energy Storage Systems (BESSs). This paper presents the outline and test results of 1.5MW and 2.5MW converters for BESS, suitable for large-scale plants. Both converters are outdoor model and have high environmental durability by applying hybrid cooling method. In terms of 2.5MW converter, adopted the latest 7th-generation IGBT modules, the capacity increases with same dimensions of the 1.5MW converter, increasing the power density up to 1.66 times of the 1.5MW converter. The efficiency of the 1.5 MW converter is achieved over 98% in the wide output range. The efficiency of 2.5MW converter is also more than 98.5% in the wide output range.