Analytical Derivation of Intersubmodule Active Power Disparity Limits in Modular Multilevel Converter-Based Battery Energy Storage Systems

• Published in: IEEE transactions on power electronics Vol. 36; no. 3; pp. 2864 - 2874
• Main Authors: Liang, Gaowen, Tafti, Hossein Dehghani, Farivar, Glen G., Pou, Josep, Townsend, Christopher D., Konstantinou, Georgios, Ceballos, Salvador
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Active power disparity; Batteries; battery energy storage system (BESS); Capacitors; Converters; Electric power distribution; Energy sources; Energy storage; Legged locomotion; Mathematical analysis; modular multilevel converter (MMC); Modular multilevel converters; Modular systems; operation limit; Power distribution; Storage systems; Topology
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2020.3014739

Due to a dramatic increase in grid-connected renewable energy resources, energy storage systems are interesting and important for future power systems, among which the modular multilevel converter (MMC)-based battery energy storage systems (BESSs) are one of the most modular, efficient, and flexible topologies. Uneven active power distribution among submodules (SMs) in the arms of an MMC-based BESS is necessary for certain applications. The main contribution of this article is to present a general analysis of the inter-SM active power disparity problem which incorporates the inherent operational constraints of the MMC converter. An analytical method to derive inter-SM active power disparity limits is introduced. The proposed analysis can help facilitate the design of MMC-based BESS for applications such as recycled batteries and hybrid battery chemistries, which can both require significant inter-SM active power disparity. The analysis formulates a criteria vector and criterion value that describes whether an MMC-based BESS is capable of supplying demanded output powers while subject to inter-SM active power disparity. Simulation and experimental results are obtained on a single-phase system with varying numbers of SMs per arm, which verifies the feasibility and generality of the proposed analytical method.