Title: Direct active and reactive power control of 3-level NPC-fed DFIG considering power ripple minimisation

Authors: Milad Yousefi-Talouki; Parviz Ramezanpour

Addresses: Department of Electrical Engineering, College of Shahid Abbaspour, Shahid Beheshti University of Tehran, P.O. Box 16765-1719, East Vafadar Blvd, Tehranpars, Tehran, Iran ' Department of Electrical Engineering, College of Shahid Abbaspour, Shahid Beheshti University of Tehran, P.O. Box 16765-1719, East Vafadar Blvd, Tehranpars, Tehran, Iran

Abstract: Despite the advantages of three-level neutral point clamp (NPC) converters compared with standard voltage source inverters (VSIs), most of the direct power control (DPC) strategies for doubly fed induction generator (DFIG) reported in the literature, only utilise VSIs. As regards three-level NPC converter generates higher number of voltage vectors compared with standard VSIs, This paper presents a DPC strategy for DFIG using three-level NPC converters in which three-level NPC voltage vectors are employed to reduce large power ripples of conventional DPC. Therefore, a new optimised switching table is derived. Using this table, DFIG provides not only elaborate active and reactive powers which track their reference values very well, but also large power ripple is compensated. Also, because of ripple reduction, total harmonic distortion of rotor current, stator current, stator voltage and grid line-to-line voltage is reduced in proposed strategy compared with conventional DPC. Simulation results show the effectiveness of proposed method and have a reasonable correspondence with theoretical and mathematical analysis.

Keywords: direct power control; DPC; multilevel converters; doubly fed induction generators; DFIG; neutral point clamp converters; discrete power equations; power ripple; total harmonic distortion; THD; simulation.

DOI: 10.1504/IJIED.2014.064091

International Journal of Industrial Electronics and Drives, 2014 Vol.1 No.3, pp.174 - 190

Received: 20 Oct 2013
Accepted: 08 Jan 2014
Published online: 30 Aug 2014 *

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