A transformer-less inverter using buck-boost type chopper circuit for photovoltaic power system

This paper presents a newly developed transformer-less single phase inverter for a photovoltaic (PV) power system. The proposed system consists of two sets of PV array and buck-boost type chopper circuit. However, the system has lower "using rate" of PV energy than that of the ordinary PV system, as each PV array is only operated in the half duration of the AC power frequency. In this paper, it is also discussed how to increase this "using rate" by varying the connected capacitor between PV array terminals. The simulation and experimental data show that the proposed inverter can supply the AC power to a utility grid line with the power factor nearly unity.