Single-Phase Virtual-Ground Transformerless Buck-Boost Inverters

This article presents a new family of transformerless buck-boost voltage-source inverter topologies for photovoltaic systems. Due to variations in irradiance, temperature, and shading effects, the terminal voltages of photovoltaic panels can vary, making the use of buck-boost inverters crucial. The proposed topologies have a virtual-ground feature that effectively mitigates the common-mode voltage issue and results in low leakage current. The simple inductor-based proposed inverter can achieve a wide gain range. Also, other counterparts obtained from extending the underlying concept of the simple inductor-based proposed inverter, such as the switched inductor, three-winding coupled inductor, and series capacitor converters, are capable of achieving high boost voltage gain with lower duty ratios. Comprehensive circuit analyses are provided, along with simulation results, to confirm the operation of each proposed topology. Additionally, experiment findings for a 500-W prototype built on the simple inductor topology are presented to support the theoretical analysis and effectiveness of the proposed designs.