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

摘要

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.