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Journal of Control Science and Engineering
Volume 2017, Article ID 6375680, 17 pages
Research Article

Rotor Speed Control of a Direct-Driven Permanent Magnet Synchronous Generator-Based Wind Turbine Using Phase-Lag Compensators to Optimize Wind Power Extraction

1Department of Electrical, Electronic and Computer Engineering, University of KwaZulu-Natal, University Road, Durban 4000, South Africa
2Department of Electric Power Engineering, Durban University of Technology, Corner of Botanic Gardens and Steve Biko Roads, Durban 4000, South Africa
3Department of Electrical, Electronics and Computer Engineering, University of Pretoria, Lynnwood Road, Pretoria 0002, South Africa

Correspondence should be addressed to Ester Hamatwi; moc.liamg@iwtamahretse

Received 12 January 2017; Revised 30 March 2017; Accepted 20 April 2017; Published 28 May 2017

Academic Editor: Carlos-Andrés García

Copyright © 2017 Ester Hamatwi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Due to the intermittent nature of wind, the wind power output tends to be inconsistent, and hence maximum power point tracking (MPPT) is usually employed to optimize the power extracted from the wind resource at a wide range of wind speeds. This paper deals with the rotor speed control of a 2 MW direct-driven permanent magnet synchronous generator (PMSG) to achieve MPPT. The proportional-integral (PI), proportional-derivative (PD), and proportional-integral-derivative (PID) controllers have widely been employed in MPPT studies owing to their simple structure and simple design procedure. However, there are a number of shortcomings associated with these controllers; the trial-and-error design procedure used to determine the P, I, and D gains presents a possibility for poorly tuned controller gains, which reduces the accuracy and the dynamic performance of the entire control system. Moreover, these controllers’ linear nature, constricted operating range, and their sensitivity to changes in machine parameters make them ineffective when applied to nonlinear and uncertain systems. On the other hand, phase-lag compensators are associated with a design procedure that is well defined from fundamental principles as opposed to the aforementioned trial-and-error design procedure. This makes the latter controller type more accurate, although it is not well developed yet, and hence it is the focus of this paper. The simulation results demonstrated the effectiveness of the proposed MPPT controller.