One-Pulse Control for STATCOM with Delta-Connected Modular Multilevel Converter

Abstract

In this study, a static synchronous compensator (STATCOM) with a delta-connected modular multilevel converter (MMC) was considered. Because a low harmonic distortion is realized with MMC topology, the switching frequency can be reduced to one-pulse, and an extremely low switching loss can be achieved. However, details on one-pulse control of an MMC-STATCOM have not been clarified. This paper describes control strategies for one-pulse control of a delta-connected MMC-STATCOM and proposes an individual balance control to balance all capacitor voltages with a low modulation index or redundant configuration. Experimental results verified the proposed balance control and one-pulse operation under stable and system fault conditions.