A Novel Dual Buck and Boost Transformer-Less Single-Phase Grid-Tied Inverter

Conventional dual buck and boost inverter with a single input dc source (DBBI-SIDS) has the satisfactory performance of high efficiency, low total capacitance, and no leakage current. Nevertheless, the main current will flow through the two individual capacitors of the inverter, which may reduce their lifetimes. In this article, a new DBBI-SIDS will be proposed, where two extra mosfet switches at line frequency are adopted to be instead of the two individual capacitors of the conventional DBBI-SIDS. Different from the conventional DBBI-SIDS, the new inverter works in the pure full bridge mode. The detailed principle of operation is presented through equivalent circuits. The static characteristics and the control strategy of the proposed inverter will be also introduced in detail. A 110-V/50-Hz/550-W prototype has been developed in the laboratory, where experimental results have verified the desired performance of the proposed inverter.