An ANF Cascaded Normalized-CF-SOHO Based Control Approach and Analysis of PV-UPQC Under Highly Non-Ideal Grid and Load Conditions

• Published in: IEEE transactions on industry applications Vol. 60; no. 5; pp. 7757 - 7770
• Main Authors: Ray, Pragnyashree, Ray, Pravat Kumar, Behera, Bhanu Pratap, Singh, Naresh
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive; Capacitors; comb filter; conditioning; Digital filters; Electric potential; Filters; Frequency estimation; fundamental frequency; Harmonic oscillators; Noise measurement; non-ideal grid; normalized; notch filter; Notch filters; Parameter estimation; Photovoltaic cells; positive sequence; Power conditioning; Power harmonic filters; PV-UPQC; Reference signals; Resonant frequencies; Robust control; SOHO; Voltage; Voltage control
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2024.3402197

Controlling and conditioning electrical power to be delivered to the critical commercial load is very crucial under non-ideal grid and load conditions. Accordingly, PV-fed UPQC (Photovoltaic fed unified power quality conditioner) is the most suitable alternative to address both voltage and current-related issues under such non-ideal scenarios. Thus, for efficient control and power conditioning, extraction of fundamental grid parameters are the prerequisites. Fundamental frequency estimation, three-phase unit template generation and fundamental active load current component extraction are the most important procedures to carry out the control process efficiently. In the proposed work, an adaptive notch filter cascaded normalized comb filter triggered second order harmonic oscillator (N-CF-SOHO) based control of PV-UPQC is illustrated. The striking feature of this control approach is its ability to generate appropriate reference signals for switching of PV-UPQC by estimating and extracting out fundamental components from highly non-ideal grid voltage and current accurately with faster execution. Notch filters (NF) being the most remarkable digital filter in separating narrow band power signal frequency is used in the proposed work to adaptively estimate the fundamental frequency by iteratively following a variable leaky least mean square (VLLMS) based updating approach. Also, NF is employed in a modified manner to exhibit the behaviour of inverse NF to extract fundamental load current component. Utilising estimated frequency, N-CF-SOHO generates fundamental voltage unit templates necessary for the control of PV-UPQC. The presented method is computationally simple, exhibits lesser run time and is robust against noise of any frequency. The presented work is authenticated both in MATLAB/Simulink platform as well as in the developed experimental prototype justifying the above-mentioned features of the system.