An Improved K-Type Seven-Level Converter Topology for Direct Grid Integration of Solar Photovoltaic Plant

This paper presents an improved K-type (IK-7) converter, which uses three solar arrays (per phase) to generate the multilevel waveforms in staircase form. This topology of the multilevel converter uses symmetric voltage sources. Hence, it helps to harness more power from the solar photovoltaic system. The proposed IK-7 configuration of the converter generates seven voltage levels with three similar PV sources and eight solid-state switches. Operating modes are well explained for the proposed converter with a proper conduction path. The presented system is operated in grid-tied mode and employs closed-loop control for converter voltage and current in dynamic solar conditions. The specific harmonic elimination strategy is applied for switching the converter to have minimum converter voltage THD. System is simulated in MATLAB and its dynamic performance is tested in different modes of solar irradiance.