An Improved Asymmetric Cascaded Multilevel D–STATCOM with Enhanced Hybrid Modulation

Abstract

Problems related to power quality, which in the last years were responsible only for small losses in low-voltage distribution systems, are now causing damage to power apparatuses and financial losses also in medium-voltage systems. The necessity of a better quality of power supply encourages the development of new specific custom power devices directly connected in medium-voltage distribution systems. It is well know that the multilevel converters are capable of being installed directly in the medium voltage, and presents several advantages when compared with conventional two-level converters. Some topologies, like the asymmetric cascaded multilevel converter, presents difficulties in regulating the voltages of all isolated dc-link capacitors. In this context, this article presents an asymmetric nineteen-level D-STATCOM (Distribution Static Synchronous Compensator) with a reactive power and dc-link regulation control loops for generic cascaded multilevel converters in order to improve the power quality in medium-voltage distribution systems. The performance of the proposed control method for a multilevel D-STATCOM is presented and evaluated in a downscaled prototype. OPEN ACCESSElectronics 2015, 4 312

Modular‐multilevel converter topologies and applications – a review

“…M-MCs provide a feasible access to build up a reliable and cost-effective STATCOM [66], with an increase the number of levels is capable to ignore the coupling transformer and substituting it with economical reactors with the power system to allow power exchange. In extension, under unbalanced conditions, it can operate continuously and it is capable of surviving symmetrical and asymmetrical faults [76] it has the fault management capability without increasing the risk of system collapse [45]. The basic circuit structure of STATCOM-based M-MCs is depicted in Fig.…”

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