Single-phase grid-connecting converter based on a MERS soft-switching concept for renewable energy and energy storage

This paper proposes a new single-phase DC/AC converter topology with soft-switching operation. This converter achieves soft-switching by using DCM (discontinuous current mode) operation and a MERS based turn-off snubber topology. The DCM operation realizes zero-current turnon and the MERS snubber topology achieves zero-voltage turn-off. The proposed converter offers bi-directional power flow single-phase DC/AC conversion with soft-switching; therefore, it is attractive for grid-connecting converter for domestic renewable energy and energy storage, including PVs (Photovoltaic) and battery energy storage devices. This paper describes operation principle, control and modulation technique for this converter, and experimental verification including loss analysis with a 1-kW pilot device.