Control and Integration of DC Power Systems

  • Po-Chun Liu

Student thesis: Master's Thesis


In recent years, DC applications and DC Microgrids in power systems have gradually drawn public attention. Droop control is well-developed for load sharing purpose to mitigate load voltage deviation in DC power systems. In order to provide stable voltage regulation subject to load dynamics, the voltage compensation control is required to maintain stable power output and render fast rejection against load disturbance. In this thesis, various control approaches and load sharing strategies for DC Microgrids are presented and validated by both simulation and experimental tests. On the other hand, wind energy possesses merits such as low capital cost and small land use. Wind energy source can be integrate as supplementary supply for DC microgrids. The offshore wind farm has become popular topic chiefly since stronger wind profile appears off the coast. The offshore wind farm is usually far from utility grid and thus requires a long transmission line system. Compared to the conventional AC-based transmission line system, the DC transmission line system consumes far less capacitive power and provides higher transmission efficiency. Thus, how to integrate the DC transmission line system into the offshore wind farm is worthy of notice. In this study, the author aims to propose a novel configuration of a DC offshore wind farm, especially for the self-excited induction generator (SEIG) with full-scale converter. Together with the proposed configuration, detailed control scheme and procedures are provided to facilitate realization of this system. The proposed SEIG-based DC configuration of offshore wind farm system and its protection scheme are validated by simulation in MATLAB/SimPowerSystem.
Date of AwardMay 2015
Original languageAmerican English
SupervisorMichael Weidong Xiao (Supervisor)


  • Power systems
  • DC applications
  • DC Microgrids
  • Voltage Deviation
  • Wind Energy
  • Wind Farms.

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