Title: An improved nearest-level modulation for modular multi-level converters

Authors: Keli Li; Yong Liao; Ren Liu; Jimiao Zhang

Addresses: School of Electrical Engineering, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400044, China ' School of Electrical Engineering, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400044, China ' School of Electrical Engineering, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400044, China ' School of Electrical Engineering, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400044, China

Abstract: Voltage balancing and switching frequency reduction are common problems of modular multi-level converters. In this research article, an improved nearest-level modulation strategy, which applies fuzzy control and minimal switching frequency pulse pattern, is proposed to coordinate voltage balancing and switching frequency reduction. The performances of voltage balancing and switching frequency reduction can be regulated by changing the parameters of the fuzzy control and the weighting coefficients of the two parts. The simulations are implemented through a high-voltage direct current system which connects a wind farm. The simulation results validate the practicability of the proposed strategy.

Keywords: fuzzy control; high-voltage direct current; modular multi-level converters; nearest-level modulation; switching frequency reduction; voltage balancing.

DOI: 10.1504/IJPELEC.2018.090720

International Journal of Power Electronics, 2018 Vol.9 No.2, pp.150 - 166

Available online: 28 Sep 2017 *

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