Title: Three-phase modified quasi-Z-source AC-AC converter for voltage sag and swell mitigation using improved modulation strategy

Authors: Naira Jeelani; Abdul Hamid Bhat

Addresses: Department of electrical Engineering, National Institute of Technology Srinagar, Jammu and Kashmir, 190006, India ' Department of electrical Engineering, National Institute of Technology Srinagar, Jammu and Kashmir, 190006, India

Abstract: From the perspective of end-users with sensitive loads, line voltage amplitude is an essential aspect of electrical energy. A three-phase modified quasi-Z-source AC-AC converter (TPM-qZAC) is proposed for mitigating voltage sag and swell. The converter features direct AC-AC conversion, eliminating the bulky dc links as used in conventional inverter-based voltage restorers. It possesses all the benefits of similar impedance source AC-AC converters (ZSACs), such as buck-boost operation, retaining or reversing the phase angle, and sharing a common ground. In addition, TPM-qZAC offers continuous input current, and similar to its single-phase counterpart, it allows the elimination of the LC output filter. A novel modulation strategy based on delta sigma modulation (DSM) is introduced for output voltage control, using an improvised variant that offers constant switching frequency (CSF). The converter's performance is evaluated through simulation studies in MATLAB/Simulink. The results indicate that TPM-qZAC modulated using the CSF-DSM technique performs well.

Keywords: bidirectional switch; AC-AC converters; constant switching frequency; pulse width modulation; PWM; delta sigma modulation; power quality; voltage sag; voltage swell.

DOI: 10.1504/IJPELEC.2024.141518

International Journal of Power Electronics, 2024 Vol.20 No.2, pp.134 - 151

Received: 01 May 2023
Accepted: 24 Sep 2023
Published online: 19 Sep 2024 *

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