Mitigation Technique for Cascaded H-Bridge Multilevel Inverters Based on Pulse Active Width Modulation

Abstract

This article considers l-level cascaded H-bridge (CHB) inverters and proposes a new modulation method based on pulse active width modulation (PAWM), capable to minimize all harmonics with order n< 2l+1 and to satisfy the European harmonic standards for medium-voltage-level applications EN 50 160 and CIGRE WG 36-05. A mathematical theorem and its proof are presented, stating the features of the procedure, which is an improvement of the selective harmonic elimination (SHE) PAWM proposed by Buccella et al. After a detailed description of the method, simulation and experimental results have been included, showing its capability to reduce low-order harmonics.