TY - GEN
T1 - Precharge strategies for isolated modular DC-DC converters under two different start-up conditions
AU - Zhang, Yi
AU - Wang, Huai
AU - Li, Binbin
AU - Xu, Dianguo
AU - Blaabjerg, Frede
N1 - Funding Information:
VI. ACKNOWLEDGMENT The author gratefully acknowledge financial support from China Scholarship Council.
Publisher Copyright:
© 2017 IEEE.
PY - 2017/8/3
Y1 - 2017/8/3
N2 - The isolated modular DC-DC converter (IMDCC) is a new topology designed to connect high-voltage direct current (HVDC) lines with different voltage levels, which ties two DC grids by using two modular multilevel converters (MMCs) via a medium-frequency transformer. Due to the large value of capacitance in the IMDCC, proper precharge strategies before the start-up are significant for the safety and reliability of the whole system. This paper presents two closed-loop precharge control strategies to fully charge the sub-module (SM) capacitors of the IMDCC, considering two different start-up operating conditions: 1) both sides of the IMDCC are connected to active sources, and 2) only one side is connected to an active source while another side is linked with passive loads. These proposed methods are aimed at regulating a controlled charging current and eliminating the inrush currents. Moreover, a capacitor balancing control is also embedded into the controller to equally charge the SM capacitors. Finally, the effectiveness of the proposed methods is verified experimentally on a downscale platform.
AB - The isolated modular DC-DC converter (IMDCC) is a new topology designed to connect high-voltage direct current (HVDC) lines with different voltage levels, which ties two DC grids by using two modular multilevel converters (MMCs) via a medium-frequency transformer. Due to the large value of capacitance in the IMDCC, proper precharge strategies before the start-up are significant for the safety and reliability of the whole system. This paper presents two closed-loop precharge control strategies to fully charge the sub-module (SM) capacitors of the IMDCC, considering two different start-up operating conditions: 1) both sides of the IMDCC are connected to active sources, and 2) only one side is connected to an active source while another side is linked with passive loads. These proposed methods are aimed at regulating a controlled charging current and eliminating the inrush currents. Moreover, a capacitor balancing control is also embedded into the controller to equally charge the SM capacitors. Finally, the effectiveness of the proposed methods is verified experimentally on a downscale platform.
KW - Isolated modular multilevel converter
KW - Modular multilevel converter
KW - Precharge strategy
KW - Two start-up conditions
UR - http://www.scopus.com/inward/record.url?scp=85029896601&partnerID=8YFLogxK
U2 - 10.1109/ISIE.2017.8001384
DO - 10.1109/ISIE.2017.8001384
M3 - Conference contribution
AN - SCOPUS:85029896601
T3 - IEEE International Symposium on Industrial Electronics
SP - 1011
EP - 1016
BT - Proceedings - 2017 IEEE International Symposium on Industrial Electronics, ISIE 2017
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 26th IEEE International Symposium on Industrial Electronics, ISIE 2017
Y2 - 18 June 2017 through 21 June 2017
ER -
