Two-stage Dual-buck Grid-tied Inverters with Efficiency Enhancement

The photovoltaic (PV) module power is two-stage conversion by traditional two-stage grid connected inverter, i.e. DC/DC, DC/AC, which will lead to serious power loss and low efficiency. This paper presents a basic idea of optimal power transmission. Part of photovoltaic power is fed to the grid directly, when the voltage of the PV module is higher than the absolute (abs) value of the grid voltage, a two-stage non-isolated dual-buck full-bridge inverter features low leakage current is presented. Operation principles and the common mode (CM), differential-mode characteristic are analyzed in details. In order to verify the feasibility of the proposed new topology and the effectiveness of theoretical analysis, a 1.5kW experimental prototype was built.