High-Efficiency Grid-Connected Inverter Topology for Low-Power Photovoltaic Applications

摘要

3 For low-power applications, such as household photovoltaic panels, the efficiency and reliability of the distributed generation system is an important issue. A high-efficiency inverter topology derived from the normal full-bridge circuit is proposed for grid-connected photovoltaic applications. In the proposed topology, a couple of diodes are added in parallel with the grid-frequency switches as freewheeling diodes working during the positive and negative half-cycles of the utility voltage, respectively, thus preventing the output current from flowing through the body diodes of switches. Because of its natural configuration, simple operation, and three-level function, the proposed topology features a high level of efficiency and reliability over a wide voltage range, and allows the best cost-effective ratio. These characteristics are compared with those of other existing advanced topologies, followed by a theoretical analysis on the output filter and the implemented circuit of modulation scheme. Experimental results from a 3 kW hardware prototype verify the feasibility of the proposed solution. (c) 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.