Control and State of Charge Balancing Technique of a Modular Multilevel STATCOM Integrated with Battery Energy Storage System

摘要

Power generation based on wind energy has seen significant growth over the last decade around the world. But this has shown negative impact on the performance of the existing grid due to injection of fluctuating power by these systems. This has necessitated to employ STATCOM and an Energy Storage System (ESS) for a grid connected Wind Energy Generating System (WEGS) at its Point of Common Coupling (PCC). This paper presents a configuration of STATCOM with integrated energy storage system which has the ability to provide active and reactive power support simultaneously for high-power/high-voltage applications. This is formed by distributing battery energy storage system over the dc-link of a Modular Multilevel Converter(MMC), which has higher redundancy and modularity compared to the two/three level based topologies. The control methodology to operate the configuration and an algorithm to balance the SoC of distributed battery modules are discussed in this paper. The complete system is simulated in PSCAD /EMTDC and the results are presented to show its effectiveness for WEGS.