Modified zeta inverter intended for single-phase grid-tied photovoltaic system

Abstract

A novel integrated converter structure intended for a single-phase grid-tied photovoltaic (PV) system is proposed in this paper. The proposed topology, named Modified Zeta Inverter (MZI), is deployed using two modified Zeta converters operating in discontinuous conduction mode. The main advantage of the MZI is its capability to step-up the input voltage while injects into the single-phase utility grid the energy produced from photovoltaic arrangements. Besides low total harmonic distortion in the grid-injected current, the proposed MZI topology was conceived to replace the conventional two-stage grid-tied system. A comprehensive study involving both static and dynamic analyses is presented. Furthermore, small-signal modeling is developed to give subsidies for designing the controllers' gains adopted in the voltage and current control loops. After a proper system sizing, it was developed a prototype setup with 432 W. Simulation and experimental results are presented to evaluate and demonstrate the feasibility of the proposed system.