Title: Direct power control with neutral-point voltage balance of grid-connected three-level NPC inverter

Authors: Zouhaira Ben Mahmoud; Mahmoud Hamouda; Adel Khedher

Addresses: Research Laboratory LATIS, ENISO, University of Sousse, Sousse, Tunisia ' Research Laboratory LATIS, ENISO, University of Sousse, Sousse, Tunisia ' Research Laboratory LATIS, ENISO, University of Sousse, Sousse, Tunisia

Abstract: Multi-level power converters are nowadays the most appropriate solution for medium-voltage grid-connected renewable energy sources (RES) such as variable speed wind-turbines and photovoltaic (PV) generators. This paper presents a three-level direct power control (DPC) scheme for a grid-connected NPC inverter with neutral point voltage (NPV) balance. The developed DPC scheme provides the active (P) and reactive (Q) powers control and commonly it preserves the voltages of the two DC-link capacitors at one half of the full DC bus voltage. At each sampling period, the adequate space vector is selected from a predefined switching table designed regarding the effect of the inverter's space vectors on both, P and Q powers, and their ability to achieve the NPV balance. Numerical simulations are carried out, and confirm the effectiveness of the proposed DPC approach in controlling the P and Q powers and minimising the fluctuations of the DC link capacitors voltages.

Keywords: direct power control; DPC; switching table; ST; neutral-point voltage; NPV; neutral-point voltage balance; grid connected-multilevel inverters; smart grid.

DOI: 10.1504/IJDSSS.2020.111007

International Journal of Digital Signals and Smart Systems, 2020 Vol.4 No.4, pp.255 - 270

Accepted: 15 Feb 2020
Published online: 28 Sep 2020 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article