A High-Frequency Transformer Integrated Three-Port Converter-Based Stand-Alone Home Energy System

Solar-powered systems with energy storage are promising energy solutions for rural areas lacking conventional grid infrastructure. The desirable features of such a system are lower device counts, continuous current ports for solar and battery, better power conversion efficiency, voltage boosting, maximum power point tracking, charge control of the battery, voltage regulation, and isolation. The existing schemes possess only some of these features. This article addresses this concern by proposing a two-stage stand-alone system with solar photovoltaic (PV) and battery. The main contribution of this article is a two-stage system consisting of a novel high-frequency transformer integrated three-port dc–dc converter (TPC) as the first stage, followed by an inverter to supply the ac loads. The operation of the proposed TPC is analyzed under different switching states with circuit diagrams and waveforms, and a control scheme is devised for the system to operate under different modes for seamless mode shifts. Further, selection guidelines for various components of the complete system are provided. The proposed stand-alone solution is validated through detailed analysis and experimental study on a 400 W prototype. The results demonstrate that the proposed system is superior to the currently available schemes.