Double LLC resonant tanks based DC-DC converter with integrated dual transformers for PV power systems

This paper proposes a double LLC resonant tanks based dc-dc converter with integrated dual transformers for photovoltaic power generation systems. It consists of a pair of power MOSFETs, LLC tanks, transformers and one voltage doubler. Both transformers including magnetizing and resonant inductors are realized on a single EE core. Primary windings of transformers are connected across half-bridge network via resonant capacitors while secondary windings are connected to voltage doubler to boost the output voltages. LLC Tanks are fed alternately by operating power switches of half-bridge network operate with interleaved half switching cycle. Therefore, power transmission from source to load is shared by two tanks circuits leading to reduction of voltage/current stress on resonant components. The validity of operational principle and performance of proposed converter is confirmed by experimental results of a 150-W prototype. The maximum efficiency of converter is measured to be 94% at input voltage of 60-V.