A Novel Cluster Balance Strategy for Delta-Type Serial Shunt Soft-Normally Open Points’ Dc Links

A novel delta-type serial shunt soft-normally open points (D-S3NOP). is proposed to face up to the challenges in distributed networks, such as power flow congestion and voltage violation. Compared with the back-to-back modular multilevel converter (BTB-MMC), D-S <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{3}$</tex> NOP offers the advantages of lower cost and smaller size within the same power regulation range. However, the cluster balance strategy of D-S <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{3}$</tex> NOP's DC links has not been thoroughly investigated. The existing cluster balance strategy is influenced by working conditions. Under certain conditions, the balancing capability is insufficient, affecting the stable operation of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$D-S^{3} N O P$</tex>. Therefore, this paper proposes a novel cluster balance strategy for the D-S <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{3}$</tex> NOP's DC links, which can operate under any working condition. The performance of the device gets optimized. The feasibility of the proposed strategy has been verified through simulation. (Abstract)