Analysis of the DPWM technique applied to a grid-connected 3L-NPC Inverter. FACTS Technologies and Power Quality in smart Grid

This paper presents a Discontinuous Pulse With Modulation (DPWM) modulation technique applied to a grid-connected three-level neutral point-clamped (3L-NPC) converter. The document proposes a methodology for the control of the active and reactive power flows in a microgrid. The control algorithm of the grid-connected system is applied for voltage control. This control technique provides independent control active and reactive power flow into the utility grid while maintain the dc-link voltage constant. As a novelty it is implements a discontinuous PWM technique in the control of the grid-connected converter. In this way the losses in the converter are reduced while the efficiency of the equipment is increased. In recent years smart grids are key components in energy distribution. Power quality and reactive compensation are essential for the correct integration of renewable energies in small microgrids. This paper presents a comparison between the conduction and switching losses in semiconductor devices depending on the modulation technique (SPWM or DPWM) used. The power losses associated with the semiconductors that constitute the 3L-NPC topology have been compared. Active and reactive power control strategies are coordinated to improve the power quality and reliability of the system in microgrids. Other purpose is to improve the voltage unbalance and harmonic compensation in stand-alone grids. The simulation of the system was developed by the Matlab/Simulink.