Analysis, Design, and Implementation of the AFZ Converter Applied to Photovoltaic Systems

Grid-tied photovoltaic (PV) installations with distributed maximum power point tracking (DMPPT) architectures include a dc-dc module integrated converter (MIC) for managing each PV panel, isolating it from the others, reducing mismatching effect and maximizing harvested power. In this article, autotransformer forward type-Zeta resonant reset (AFZ) is proposed as DMPPT architecture's MIC candidate. The main characteristics of AFZ are high versatility due to its voltage step-up step-down capability; use an optimized only two windings, complexity losses component; good dynamic performances, like ones; low number components simplicity feasibility associated just one active switch. Besides, soft switching transitions achieved thanks reset. steady-state theoretical analysis, considering leakage inductance, presented. also studied in frequency domain, obtaining small-signal transfer functions. A design procedure based on requirements 100-kW grid-tied installation described, yielding 225-W prototype efficiencies up 95.6%. Experimental results validate analysis.