Elephant herding algorithm-based optimal PI controller for LVRT enhancement of wind energy conversion systems

Abstract

This article introduces an optimal PI controller optimized by elephant herding algorithm (EHA) to control the grid-tied four-phase 8/6 switched reluctance generator (SRG). This controller is introduced for enhancing the low voltage ride through (LVRT) capability of the grid-tied SRG during faulty conditions that affect the SRG output voltage by regulating the off-delay angle of the generator. These faulty conditions include faults taken place at the point of connection (POC) of the SRG to the grid and wind speed variations. The proposed optimized PI controller regulates the off-delay angle of the generator to keep the voltage at the POC within acceptable limits. Maintaining these acceptable voltage limits during faulty conditions that keeps the generator in connection to the grid and makes the generator complying with the grid codes. Comparison between EHA optimization technique, cuckoo search optimization and particle swarm optimization (PSO) were presented to illustrate the effectiveness of the modern optimization technique used, EHA. An experimental verification of the proposed system is introduced by rewinding the stator and reshaping the rotor of three-phase induction machine to form four-phase, 8/6 SRG. Finite element method (FEM) based on ANSYS software is utilized to get the magnetic characteristics of the reconstructed 8/6 SRG after drawing the 3-D geometrical dimension in AUTOCAD.

Keywords

• Elephant herding optimization
• LVRT
• PI controller
• Wind energy systems