An Input Independent Output Series Energy-Stored Quasi-Z Source LLC Converter for Application to DC Photovoltaic System

This paper proposes a new topology which combines energy-stored(ES) quasi-Z source(qZS) converter and LLC resonant converter. The operation principle and voltage gain of the proposed topology are analyzed in detail. The proposed topology is constructed into an input independent output series (IIOS) system to realize medium voltage direct source (MVDC) integration of renewable energy. A comprehensive control strategy for the IIOS qZSI-LLC is proposed to track the PV panel’s maximum power point(MPP), manage the battery power and balance the module output voltage. Both the operation principle and the control strategy are verified by simulation.