Hysteresis Current Controller based Transformerless Split Inductor-NPC - MLI for Grid Connected PV- System

Abstract

Non-conventional energy sources are breeding more and more widespread, mainly due to the fact of that they generate energy by keeping the spotless environment .The Multilevel inverters are highly being used in high-power medium voltage applications due to their better performance compared to two-level inverters. Among various types of multilevel inverters, neutral point clamped multi-level inverter (NPC-MLI) is suitable for a transformerless photovoltaic (PV) grid-connected system. Eliminating the leakage current is one of the most key issues for transformerless inverters Split Inductor MLI (SI-MLI) in grid-connected PV system applications, where the technical challenge is how to keep the system common-mode voltage constant to eradicate the leakage current & shoot-through possibility. The proposed elite Hysteresis Current Control (HCC) offers an admirable current control performance to SI-NPC-MLI. It is performed based on the error current value (Δi) and hysteresis Band value (h) produced between SI-MLI and grid. The proposed SI-NPC-MLI-HCC topology is guarantees for no shoot-through possibility and also maintains lower Voltage and current total harmonics distortion (THD). Test results verify the theoretical analysis and the validity of the system is verified through MATLAB/Simulink and the results are compared with conventional topologies