A novel synchronous H6 for improving light load efficiency of bidirectional inverters in a DC distribution system

Abstract

This paper presents a method for overcoming reduced light-load efficiency imposed by bidirectional inverters integrated with a DC distribution system powered by renewable energy. An evaluation of existing topologies to achieve optimal efficiency is presented, and loss breakdown under light-load is investigated using analytic models and PSIM simulation. The study proposes a novel synchronous H6 transformer-less topology. The results show that the proposed topology at achieves 98.3% light load efficiency (at 20% load) when operated in inverter mode, whereas 96.5% is obtained at full load, both which are higher than the standard H6 topology efficiency by 4.5% and 1.5%, respectively. The rectifier mode shows similar levels of improvement of 4% at light load and 1.2% for under full load conditions.