Compensation of Voltage Sags and Swells Using Dynamic Voltage Restorer Based on Bi-Directional H-Bridge AC/AC Converter

Yu-Kai Chen,Xian-Zhi Qiu,Yung-Chun Wu,Chau-Chung Song

doi:10.3390/pr9091541

Yu-Kai Chen, Xian-Zhi Qiu + Show 2 more

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https://doi.org/10.3390/pr9091541

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Abstract

In this paper, the compensation of voltage sags and swells using a dynamic voltage restorer (DVR) based on a bi-directional AC/AC converter is presented for stabilizing single-phase AC line voltage. The H-bridge AC/AC converter with bi-directional switches and without bulk capacitor is adopted as the power topology of the proposed system. The proposed novel topology of DVR is adopted to compensate both voltage sag and swell conditions. Additionally, the power factor is closed to unity because a bulk capacitor is not required. The inner and outer loop control is proposed to improve the response with gain scaling; gain control is adopted to reduce the overshoot. Finally, a 2 kVA prototype has been implemented to verify the performance and accuracy of the control method for the DVR system. The peak efficiency of the system is up to 94%, and it can compensate 50% voltage swells and 25% voltage sags.

Highlights

Thanks to industrial automation, in recent years electronic facilities are increasingly demanding with respect to the quality of their electricity, such as sudden voltage sags/swells, and demand for an output voltage with low harmonic distortion
The voltage swell range set to 25%,waveforms the winding ratioDVR
To design the low-frequency transformer’s turn ratios, we considered the range within which voltage swells and voltage sags occur

Summary

Introduction

In recent years electronic facilities are increasingly demanding with respect to the quality of their electricity, such as sudden voltage sags/swells, and demand for an output voltage with low harmonic distortion. Sudden voltage sags (caused mainly by the starting of high-power motors or by short circuit) are normally the most common disruptions for electrical systems. They account for more than 90% of power quality issues. Modern semiconductor facilities, such as computer communications systems, measurement instruments and production machineries, are all very sensitive to voltage changes. Even a mere three to five cycles of voltage change can hang systems and affect factory production It follows, that since all of the high-tech industries use computerized, automated systems that are highly voltage sensitive, investment in stable voltage output and power quality is a required necessity

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