Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Unbalancing Voltage Control of LVDC Bipolar Distribution System for High Power Quality
Authors Hee-Jun Lee ; Soo-Choel Shin ; Jin-Wook Kang ; Chung-Yuen Won
DOI 10.6113/TKPE/2016.21.6.486
Page pp.486-496
ISSN 1229-2214
Keywords 3-level AC/DC converter; LVDC distribution system; Bipolar voltage control
Abstract The voltage unbalance of an LVDC bipolar distribution system was controlled for high power quality. Voltage unbalance may occur in a bipolar distribution system depending on the operation of the converter and load usage. Voltage unbalance can damage sensitive load and lead to converter accidents. The conditions that may cause voltage unbalance in a bipolar distribution system are as follows. First, three-level AC/DC converters in bipolar distribution systems can lead to voltage unbalance. Second, bipolar distribution systems can be at risk for voltage unbalance because of load usage. In this paper, the output DC link of a three-level AC/DC converter was analyzed for voltage unbalance, and the bipolar voltage was controlled with algorithms. In the case of additional voltage unbalance according to load usage, the bipolar voltage was controlled using the proposed converter. The proposed converter is a dual half-bridge converter, which was improved from the secondary circuit of a dual half-bridge converter. A control algorithm for bipolar voltage control without additional converters was proposed. The balancing control of the bipolar distribution system with distributed power was verified through experiments.