Novel Step-Up Transformerless Inverter Topology for 1-φ Grid-Connected Photovoltaic System

In this article, a novel step-up transformerless inverter topology is presented for the grid-connected solar PV system. The proposed topology has the features of a dc-dc step-up converter and two-level inverter. First, it offers the transformerless grid connection of solar PV system with negligible leakage current and higher efficiency, and second, it provides inherent high gain step-up so that low-voltage solar PV modules can be directly connected. In addition, the proposed topology has low-voltage stress, less power losses, and requires fewer independent gate drive signals compared to the other existing transformerless inverter configurations with voltage boosting capability. The design, modes of operation, analysis, and developed PWM strategy, for the proposed inverter topology, are presented in detail. Furthermore, the system performance is validated experimentally through a 400 VA laboratory prototype. The experimental investigation demonstrates that the proposed topology results in transformerless voltage boosting while achieving improved system efficiency.

Automated summary

This article introduces a novel step-up transformerless inverter topology for grid-connected solar PV system, which offers transformerless grid connection with high efficiency and boosting capability for low-voltage solar PV modules, as well as low-voltage stress and less power losses compared to existing configurations. The design, modes of operation, analysis, and PWM strategy of the proposed inverter topology are detailed, and experimental validation shows improved system efficiency with transformerless voltage boosting.