A Novel PWM Modulation Strategy for DC Voltage Balancing in Cascaded H-Bridge Multilevel Converters

This paper presents a novel Voltage Balancing PWM modulation strategy for Cascaded H-Bridge multilevel converters. These converters have been classically commu-tated at fundamental line-frequencies, but the evolution of Power Semiconductors has allowed to increase switching frequencies and the power ratings of these devices, permitting the use of PWM modulation techniques. This paper presents a new PWM modulation strategy that solves the DC Bus voltage balancing problems that appear in the cascaded converter working in reactive power compensation (STATCOM) applications.