A New Topology With High Efficiency Throughout All Load Range for Photovoltaic PCS

In this paper, a new topology is proposed that can significantly reduce the converter rated power and increase the efficiency of total photovoltaic (PV) system. Since the output voltage of PV module has very wide operating range, in general, the DC/DC converter is used to produce constant high-DC-link voltage for DC/AC inverter. According to the analysis of the proposed topology, only 20% of total PV system power is processed by the DC/DC power conversion stage. The DC/DC power conversion stage used in proposed topology has flat efficiency curve throughout all load range and very high efficiency characteristics. In the proposed topology, because the converter efficiency curve is almost flat throughout all load range, the total system efficiency at light load is dramatically improved. The proposed topology is implemented for 250-kW power conditioning system. This system has only three DC/DC power conversion stage with 24-kW rated power. It is only one-third of total system power. The experimental results show that the proposed topology has good performance.