A 25-Level Hybrid Cascaded Multilevel Converter with Capacitor Voltage Balancing Scheme

Multilevel converters (MLC) have attracted significant attention in both industry and research due to their increased power capacity, reduced output harmonics, and minimized commutation losses. However, their adoption is impeded by increased complexity, necessitating a larger number of power devices, passive components, and intricate control circuitry, especially as voltage levels increase. This paper introduces a hybrid 25-level MLC topology with a capacitor voltage balancing scheme. The proposed configuration consists of two power cells per phase, each consisting of six uni-directional, two bidirectional switching devices, and two capacitors. In this study, the switching scheme, capacitor voltage balancing, and selection of switched capacitors are studied. In simulation studies, 25 levels of the proposed configuration are achieved with a total harmonic distortion (THD) of 4.57% in the leg and 2.75% in line voltage waveforms.