Abstract

In this article, an improved dc-link voltage regulation strategy is proposed for grid-connected converters applied in dc microgrids. For the inner loop of the grid-connected converter, a voltage modulated direct power control is employed to obtain two second-order linear time-invariant systems, which guarantees that the closed-loop system is globally exponentially stable. For the outer loop, a sliding mode control strategy with a load current sensor is employed to maintain a constant dc-link voltage even in the presence of constant power loads at the dc-side, which adversely affect the system stability. Furthermore, an observer for the dc-link current is designed to remove the dc current sensor at the same time improving the reliability and decreasing the cost. From both simulation and experimental results obtained from a 15-kVA prototype setup, the proposed method is demonstrated to improve the transient performance of the system and has robustness properties to handle parameter mismatches compared with the input-output linearization method.

Original languageEnglish
Article number9080581
JournalI E E E Transactions on Industrial Electronics
Volume68
Issue number6
Pages (from-to)4977-4987
Number of pages11
ISSN0278-0046
DOIs
Publication statusPublished - Jun 2021

Keywords

  • DC Microgrid
  • Direct Power Control
  • Grid-Connected Converter
  • Observer
  • Sliding Mode Control

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