Abstract

This paper presents a proposed Horse Herd Optimization (HHO) technique for tuning a PI controller of a Multi-Function Converter (MFC) system for mitigating harmonic distortion caused by a Variable Speed Drive (VSD) operated in a modified Cigre benchmark 14-bus distribution network, in addition to provide reactive power compensation for achieving unity power factor at the Point of Common Coupling (PCC). First, voltage and current harmonics at all buses are calculated in accordance with the IEEE Std. 519-2022 requirements. Five cases are considered for studying the harmonic distortion mitigation, using the MFC system: (i) no MFC; (ii) installing an MFC controlled by a hysteresis controller; (iii) installing an MFC controlled by a fuzzy logic controller; (iv) installing an MFC controlled by a PI controller tuned by Particle Swarm Optimization (PSO) method; and (v) installing an MFC system controlled by a PI controller tuned by the HHO method. Second, the reactive power compensation using the MFC system is investigated when switching an RL load at the VSD busbar for achieving unity power factor. Simulation studies are performed based on the MATLAB/Simulink software. The results show that the HHO-tuned PI controller provides the most reduction in currents and voltages harmonic distortions compared to the other controllers. Moreover, the HHO-tuned PI controller can provide the required reactive power for achieving unity power factor.

Key words: Fuzzy logic control; Horse herd optimization; Hysteresis control; Multi-function converter system; PI controller; Reactive power compensation; Variable speed drive.