Enhancing VA sharing between the shunt and series APFs of UPQC with a modified SRF-PAC method

• Published in: IET power electronics Vol. 13; no. 2; pp. 275 - 285
• Main Authors: Patel, Ashish, Mathur, Hitesh Datt, Bhanot, Surekha
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 05.02.2020
• Subjects: active filters; active power filter supplies total reactive power demand; conventional UPQC; modified power angle estimation; modified SRF‐PAC method; power angle control method; power filters; power harmonic filters; power supply quality; reactive load power; reactive power; reactive power control; Research Article; series APF; shunt; SRF‐based PAC methods; synchronous reference frame theory‐based; unbalanced VA loading; unified power quality conditioner; VA rating; VA sharing; voltage control; series APF; modified power angle estimation; shunt; synchronous reference frame theory-based; VA sharing; active power filter supplies total reactive power demand; power harmonic filters; conventional UPQC; active filters; power supply quality; power filters; unified power quality conditioner; VA rating; reactive power; reactive load power; reactive power control; modified SRF-PAC method; unbalanced VA loading; SRF-based PAC methods; power angle control method; voltage control
• ISSN: 1755-4535; 1755-4543; 1755-4543
• DOI: 10.1049/iet-pel.2018.6329

This study proposes a synchronous reference frame (SRF) theory-based modified power angle control (PAC) method for unified power quality conditioner (UPQC). In the steady state of conventional UPQC, shunt active power filter (APF) supplies total reactive power demand, and series APF sits idle, leading to unbalanced VA loading of the two APFs and increase in overall VA rating of UPQC. PAC methods of UPQC have been devised for reducing the unbalance in VA loading of series and shunt APFs of UPQC by sharing reactive load power between the two APFs. SRF-based PAC methods are robust, but existing ones support only small values of power angle, and thereby limit the improvement in unbalance of VA loading of series and shunt APFs. In this work, a modified SRF-PAC method is proposed to support larger values of power angle, to load the two APFs in proportion to their VA ratings and thus yield smaller unbalance in VA loading of the two APFs of UPQC. Also, a modified power angle estimation is proposed to ensure that voltage and VA load on series converter does not go beyond the rated values. Controller hardware in loop simulations and hardware experiments validate the proposed control method.