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http://dx.doi.org/10.21289/KSIC.2022.25.3.423

A Study on Automatic Multi-Power Synchronous Transfer Switch using New DFT Comparator  

Kwak, A-Rim (Dept. of Electrical Engineering, Chonnam National University)
Park, Seong-Mi (Dept. of Lift Engineering, Korea Lift College)
Son, Gyung-Jong (Dept. of Electrical Engineering, Chonnam National University)
Park, Sung-Jun (Dept. of Electrical Engineering, Chonnam National University)
Kim, Jong-Cheol (Green Energy Institute)
Publication Information
Journal of the Korean Society of Industry Convergence / v.25, no.3, 2022 , pp. 423-431 More about this Journal
Abstract
The UPS(Uninterruptible Power Supply) system operates in the battery charging mode when the grid is normal, and in the UPS mode, which is the battery discharge mode when a grid error occurs. Since the UPS must supply the same voltage as the grid to the load within 4 [ms] in case of a grid error, the switching time and power recovery time should be short when controlling the output voltage and current of the UPS, and the power failure detection time is also important. The power outage detection algorithm using DFT(Discrete Fourier Transform) proposed in this paper compares the grid voltage waveform with the voltage waveform including the 9th harmonic generated through DFT using Schmitt trigger to detect power outage faster than the existing power outage monitoring algorithm. There are advantages. Therefore, it is possible to supply instant and stable power when switching modes in the UPS system. The multi-power-applied UPS system proposed in this paper uses DFT, which is faster than the conventional blackout monitoring algorithm in detecting power failure, to provide stable power to the load in a shorter time than the existing power outage monitoring algorithm when a system error occurs. The detection method was applied. The changeover time of mode switching was set to less than 4 [ms], which is 1/4 of the system cycle, in accordance with KSC 4310 regulation, which was established by the Industrial Standards Council on the regulation of uninterruptible power supply. A 10 [kW] UPS system in which commercial voltage, vehicle generator, and auxiliary diesel generator can be connected to each of the proposed transfer devices was constructed and the feasibility was verified by conducting an experiment.
Keywords
UPS(Uninterruptible Power Supply); Multi Powered Switching; DFT(Discrete Fourier Transform); PI Control; Power Failure Detection Algorithm;
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Times Cited By KSCI : 1  (Citation Analysis)
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