Hierarchical Control of Parallel AC-DC Converter Interfaces for Hybrid Microgrids

Xiaonan Lu, Josep M. Guerrero, Kai Sun, Juan Carlos Vasquez, Remus Teodorescu, Lipei Huang

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212 Citations (Scopus)
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Abstract

In this paper, a hierarchical control system for parallel power electronics interfaces between ac bus and dc bus in a hybrid microgrid is presented. Both standalone and grid-connected operation modes in the dc side of the microgrid are analyzed. Concretely, a three-level hierarchical control system is implemented. In the primary control level, the decentralized control is realized by using the droop method. Local ac current proportional-resonant controller and dc voltage proportional-integral controller are employed. When the local load is connected to the dc bus, dc droop control is applied to obtain equal or proportional dc load current sharing. The common secondary control level is designed to eliminate the dc bus voltage deviation produced by the droop control, with dc bus voltage in the hybrid microgrid boosted to an acceptable range. After guaranteeing the performance of the dc side standalone operation by means of the primary and secondary control levels, the tertiary control level is thereafter employed to perform the connection to an external dc system. Meanwhile, the impact of the bandwidth of the secondary and tertiary control levels is discussed. The closed-loop model including all the three control levels is developed in order to adjust the main control parameters and study the system stability. Experimental results of a 2×2.2 kW parallel ac-dc converter system have shown satisfactory realization of the designed system.
Original languageEnglish
JournalI E E E Transactions on Smart Grid
Volume5
Issue number2
Pages (from-to)683 - 692
Number of pages10
ISSN1949-3053
DOIs
Publication statusPublished - Mar 2014

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Keywords

  • Hierarchical control
  • Hybrid microgrid
  • Parallel power electronics converter interface

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