A Hybrid Fuzzy Based Modular Multilevel Cascade Converters for Back-To-Back System without Dc-Link Capacitor

Abstract

This paper presents a Hybrid-Fuzzy application of the modular multilevel cascade converter based on double-star chopper-cells (MMCC-DSCC) to a back-to-back (BTB) system for installation on power distribution systems. The DSCC is characterized by a cascade connection of multiple chopper-cells per leg, leading to flexible circuit design, low voltage steps, low EMI emission, and low harmonic voltage and current. The DSCC-based BTB system is equipped with neither dc capacitor nor voltage sensor on the common dc link. The paper designs, constructs, and tests a three-phase, 200-V, and 10-kW downscaled system to verify and justify its operating principles and performance. Experimental and simulated results agree well with each other, showing a promising possibility of the DSCC-based BTB system.
Keywords— Hybrid-Fuzzy; Asynchronous intertie; back-to-back (BTB) systems; grid-connected power converters; modular multilevel cascade converters (MMCCs)