Title: Power quality improvement and seamless transfer in a grid-connected microgrid system using H_∞ controller

Authors: V. Lavanya; N. Senthil Kumar

Addresses: School of Electrical Engineering, Vellore Institute of Technology, Chennai, Tamil Nadu, India ' Centre for Smart Grid Technologies, School of Electrical Engineering, Vellore Institute of Technology, Chennai, Tamil Nadu, India

Abstract: In this paper, an H_∞ controller-based cascaded control strategy has been discussed and analysed for the improvement of power quality and smooth seamless transition between the operating modes in a grid-connected microgrid system. The control strategy involves two control loops namely, an outer grid current control loop and an inner local load voltage control loop. Both the control loops are designed using H_∞ repetitive controllers. Particle swarm optimisation (PSO) technique is used to optimise the weighting parameters of the H_∞ controller to design an optimal controller for achieving the desired performance. The main objective of the control strategy is to minimise the harmonic content present in the load voltage and the grid current ensuring smooth transition between the operating modes of the microgrid without any noticeable transients. The H_∞ repetitive controller with optimised weighting parameters outperforms the other traditional controllers in achieving better dynamic response with reduced THD.

Keywords: microgrid; seamless transfer; H-infinity controller; H_∞; grid-connected; islanded; three-phase inverter; power quality.

DOI: 10.1504/IJAAC.2023.134553

International Journal of Automation and Control, 2023 Vol.17 No.6, pp.657 - 685

Received: 22 Nov 2021
Accepted: 30 Jan 2023
Published online: 27 Oct 2023 *

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