Fuzzy-PI Controller based Modulated Multilevel UPQC under Faulty Conditions

Background: This paper presents voltage and current quality improvement in high/medium electrical distribution system using modulated multilevel unified power quality conditioner (MM-UPQC). Nowadays, power quality is one of the major issues due to the increase in usage of more non-linear loads in agricultural, commercial, industrial sectors. The industrial loads produce large amount of harmonics and power imbalances, which cause various power quality related issues like poor power factor, voltage sag, voltage swell, voltage interruption etc. Methods: The prime objective of this work is to design fuzzy-PI based controller based modulated multilevel UPQC for mitigation of issues related to power quality under unsymmetrical fault conditions such as LG fault and LLG fault. Results: This paper uses Instantaneous Reactive Power Theory (IRP) for phase angle adjustment with PI-fuzzy controller scheme to generate accurate reference signal for shunt and series controller of MM-UPQC. The detailed comparative analysis results of simultaneous voltage sag, swell, harmonics compensation and unsymmetrical faults mitigation are presented alongwith the MATLAB/SIMULINK software. Conclusion: Total harmonic distortion analysis is tabulated with PI and fuzzy-PI controller based MM-UPQC for different operating conditions in 4.16 KV distribution system.