Single-Stage Single-Phase H6 and H8 Non-Isolated Buck-Boost Photovoltaic Inverters

In this study, a novel full-bridge single-stage transformerless buck-boost inverters are proposed. The output ac voltage of the proposed inverters can be greater or lower than the input dc voltage depending on the duty ratio. The main features of the proposed inverters are their bidirectional capability, continuous output current, simple operation, handling of reactive power, and stepping up and down the input voltage in a single stage. The proposed inverters are named H8 and H6 buck-boost inverters. The proposed H8 inverter has only two switches working at high frequency at a time while the proposed H6 inverter has only one switch working at high frequency. As a result, the proposed inverters have low power losses and higher efficiency than most of the conventional topologies. Detailed circuit analysis of the proposed inverters is presented. To verify the performance of the proposed inverters, a hardware prototype of the proposed inverters are implemented and tested for the input voltage of 100-200 V, an output voltage of 110 Vrms at 60 Hz, and an output power of 800 W.