Novel Single-Phase Grid-Tied NPC Five-Level Converter with an Inherent DC-Link Voltage Balancing Strategy for Power Quality Improvement

This paper presents a novel single-phase grid-tied neutral-point-clamped (NPC) five-level converter (SPFLC). Unlike the literature on NPC topologies, proposed one is capable of inherently balancing voltage DC-link split capacitors. For this purpose, simple Multicarrier Phase Disposition (MPD) Pulse Width Modulation (PWM) technique used, thus avoiding both complex modifications to Space Vector (SVM) and offset injections into carrier based (CB) PWM, as commonly done in most conventional algorithms. Bearing mind that strategy only requires measuring capacitors’ voltages sign output current, it has very low complexity. The developed not straightforwardly implemented but also effective for obtaining symmetrical undistorted levels from multilevel converter, well significantly improving power quality SPFLC and, turn, grid current. simulation results obtained with MATLAB-SimPowerSystems experimental prototype built laboratory validate topology strategy, by showing good performance under step-changes exhaustive operating test conditions.