Low voltage ride through function for the high voltage AC ports of four-port power electronic transformers
NIE Haozhe, SHEN Yu, ZHAO Zhengming, WEN Wusong, YUAN Liqiang
State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
Abstract：The widespread use of power electronic transformers in power systems has led to more research on their operational safety and stability. The voltage sag in the alternating current (AC) port of the power electronic transformer caused by a short circuit fault of the grid connection point can lead to serious instabilities which can slow the power grid recovery. The instability mechanism of the high voltage AC port of a modular four-port power electronic transformer is analyzed in terms of the energy characteristics when a voltage sag fault occurs. Then, a low voltage ride through control scheme is given to maintain safe, stable operation of the power electronic transformer during the fault. This scheme provides a low voltage ride through function by switching the power balance port and the power electronic transformer control strategy. Finally, this low voltage ride through control scheme is verified using DSIM simulations which shows that the scheme effectively improves the safety and stability of the power electronic transformer and provides low voltage ride through in multi-port power electronic equipment.
聂浩哲, 沈瑜, 赵争鸣, 文武松, 袁立强. 四端口电力电子变压器高压交流端口的低电压穿越功能[J]. 清华大学学报（自然科学版）, 2021, 61(10): 1097-1105.
NIE Haozhe, SHEN Yu, ZHAO Zhengming, WEN Wusong, YUAN Liqiang. Low voltage ride through function for the high voltage AC ports of four-port power electronic transformers. Journal of Tsinghua University(Science and Technology), 2021, 61(10): 1097-1105.
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2021, Vol. 61 
