Optimization of a transformer used for LLC resonant DC-DC converters for photovoltaic cells

This paper proposes a method to improve the power efficiency in the half-bridge LLC resonant DC-DC converter. The optimum design of a transformer is discussed to improve power efficiency. The interlinkage magnetic flux in the primary and secondary wires causes eddy currents, which results in a power loss. This study demonstrates that power loss can be reduced through optimum design of the strand diameter of the Ritz wire. A maximum efficiency of 98% was achieved using a Ritz wire diameter of 0.03 φ.