Capacitor voltage balancing of hybrid converter based on nearest level control

Hybrid converter is recently introduced converter topology for high voltage applications. The converter comprises combination of director switches and a wave-shaping circuit assembled with capacitors. Director switch is made of cascaded IGBTs and waveshaping circuit consisting stack of H-bridge cells. This paper presents Nearest level control technique for hybrid converters, resulting in balanced capacitor voltages. Influence of variable modulation indices on capacitor voltage of wave-shaping circuit and THD of converter output voltage are analysed. A specific modulation index range plays a crucial role in balancing of capacitor voltages. Simulation results proves the validity of proposed modulation technique.