Leakage Current Reduction in Four-leg Inverter Utilizing Three-Dimensional Virtual Voltage Vector-based Predictive Control

It is possible to connect PV systems to the electrical grid either with a galvanic isolation transformer (transformer) or without one (transformer-less). Galvanic isolation is provided by the low-frequency transformer; nevertheless, this results in an increase in the transformer's size, cost, and losses. Alternatively, transformer-less PV systems increase leakage current. The leakage current is dependent on a number of characteristics, primarily the topology and switching strategy of the inverter. Since switching scheme change does not require new hardware, it is a cost-effective way to minimize leakage current. Common-mode voltage (CMV) fluctuations in transformer-less systems result in high-frequency harmonics and leakage current flow. This study offers a model predictive current control (MPCC) technique for a three-phase four-leg voltage source inverter using three-dimensional (3-D) virtual voltage vectors (VVVs) or (V-3) (VSI). To limit CMV amplitude, leakage current, and overall harmonic distortion of the output current load, only selected vectors are employed. This work presents fresh research into the impact of the suggested method and the use of virtual voltage vectors on leakage current and output current total harmonic distortion (THD) in a two-level, three-phase, four-leg inverter.