Analysis and design of distributed transformers for solar power conversion

In this paper, a high efficiency, low profile design of distributed transformers (DT) for grid-tied photovoltaic (PV) inverter is presented. The proposed DTs fully integrated into the dual-flyback converter maximize the DC/DC stage efficiency in whole load conditions. The developed DTs with the built-in current sensing transformer allows the converter works in boundary conduction mode (BCM) or discontinues conduction mode (DCM) due to the variable nature of solar power with zero current switching (ZCS). Analytical loss model is established to optimize the value of magnetizing inductance which determines the switching frequency and converter overall efficiency. Various techniques are also taken to minimize the winding loss of the DTs. The experimental prototype employing the DTs achieves over 96% efficiency at full load condition.