Three-Phase Single PV Array fed Scott-Ternary Multilevel Converter with Nearest Level Control

A Scott-ternary multilevel converter (ST-MLC) based solar photovoltaic system is presented in this paper. This system employs a single PV array as an input source and two cascaded voltage source converters (VSCs) are used to feed a three-phase grid-tied network. The legs of VSCs are cascaded to form a two-phase network. The multi-winding transformers are Scott-connected for the development of a minimum device count based nine-level three-phase power conditioning system. The turn ratios of transformers are selected in ternary progression for the generation of higher levels. Solar power is fed from two-phase to a three-phase system with balanced grid currents. The modeling and control of the system are presented with the nearest level control (NLC) strategy to have minimum losses in the switching of devices. The MATLAB based simulated results show performance of the solar photovoltaic system at steady-state and dynamic irradiance. The harmonic performance is analyzed to alleviate power quality problems. Moreover, a comparative analysis is also covered for the ST-MLC.