A Four-level Hybrid-Clamped Converter With Natural Capacitor Voltage Balancing Ability

This paper presents a novel four-level hybrid-clamped converter topology which is composed of eight switches and one flying capacitor per phase. The operating principle is introduced and phase-shifted pulse width modulation is used to control this converter. A detailed analysis of the average currents through the flying capacitor and neutral points of the dc-link is presented. Based on the analysis, it can be concluded that the voltages across the flying capacitor and dc-link capacitors can be naturally balanced under ideal and steady-state condition. A low-power three-phase prototype is built up and experimental results are presented to validate the proposed topology and modulation method.