Power flow control and power quality analysis in power distribution system using UPQC based cascaded multi-level inverter with predictive phase dispersion modulation method

Abstract

Power quality is associated with the ability of utilities to provide electrical power without interruption. One of the major concerns in the electrical industry today is the issue of power quality over major loads. This work presents a Cascaded H-Bridge Multi-Level Inverter (CHBMLI) based unified power quality conditioner (UPQC) for the compensation of voltage sag/swell in the source side and current harmonics in the load side due to the non-linear loads. A predictive control based algorithm called as predictive phase dispersion modulation (PPDM) is used in the proposed system for the control of series and shunt active power filter of the UPQC. The shunt and series active power filter is connected back to back with a common DC link capacitor. The objectives of the proposed algorithm is to maintain a constant DC link voltage and to control the switching pulses of the CHBMLI according to the variations of the current in the load side and also the voltage unbalances in the source side. The performance of the UPQC is significantly improved with the proposed CHBMLI based UPQC than the conventional Voltage Source Inverters (VSI) based UPQC. The algorithm used in this work reduces the computational burden than the conventional model predictive controllers. The proposed CHBMLI based UPQC with PPDM technique is validated through simulation studies using MATLAB and a hardware prototype also realized and the results are investigated.