A Novel 2$N$ + 1 Carrier-Based Pulse Width Modulation Scheme for Modular Multilevel Converters With Reduced Control Complexity

Abstract

This article presents a simple pulse width modulator to achieve both N + 1 and 2N + 1 modulation in a modular multilevel converter. The proposed implementation needs a single triangular waveform to control a modular multilevel converter with a large number of submodules. Hence, the proposed approach significantly reduces the required triangular carrier count and solves the practical implementation issues associated with the carrier-based pulse width modulation schemes in the digital control platforms. The performance of the proposed approach is validated with detailed experimental studies. The results show that the proposed strategy effectively generates a multilevel voltage waveform at the load terminals. Furthermore, the performance of the proposed approach is compared with the traditional phase-shifted carrier pulse width modulation schemes. In addition, it can be easily applied to the n-level modular multilevel converter with any type of submodule configuration.