Three-Phase Transformerless Buck-Inverter Topologies for PV Grid-Tied Systems: A Review

With an emphasis on common-mode voltage (CMV) and leakage current suppression, this research offers a thorough examination of three-phase, two-level buck inverter topologies for transformerless (TL) grid-tied photovoltaic (PV) systems. A comprehensive classification and comparative evaluation of modern voltage-source inverter (VSI) and current-source inverter (CSI) topologies, such as H6, H7, H8, H10, and hybrid setups, constitute the paper’s main contribution. The main conclusions show that CSIs naturally offer better leakage current suppression, albeit at the expense of cost and complexity, while sophisticated VSIs (such as specific H8 and H10 topologies) in conjunction with specialized modulation techniques (like modified discontinuous PWM) provide balanced performance. The study finds intriguing research possibilities for further work in this area and indicates that the ideal topology depends on the specific application.