An HESS Based on a Modified MMCC-TSBC Converter Integrating Energy Storages

This paper presents a modified modular multilevel cascaded converter based on a triple star bridge cell(MMCCTSBC)for integrating different types of energy storage to form a hybrid energy storage system(HESS).The proposed HESS comprises battery energy storage,supercapacitor energy storage and a doubly-fed induction machine(DFIM)based variable speed pump storage(VSPS).Different low-rated energy storage units can be intermixed in this converter to form an HESS.This is possible due to the modular structure of the modified converter and provides an advantage in a high-power energy storage system.To validate the performance of HESS,real-time power variation data is accumulated from online sources and a weighted median filter(WMF)is employed for generating appropriate references for battery energy storage system(BESS)and supercapacitor storage to mitigate both low frequency and high-frequency power variations.Here,the control approach permits independent regulation of grid current and DFIM current through the modified MMCC-TSBC converter.The simulation and experimental results validate the effectiveness of the control scheme for the proposed HESS.