Control Strategy of Single-Phase Hybrid-Mode Ćuk Inverter for LVRT Capability

Byeongcheol Han, Changkyu Bai, Jih Sheng Lai, Minsung Kim

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

This article proposes a control strategy for a Ćuk module-integrated inverter (MII) with hybrid operation mode for low-voltage ride-Through (LVRT) capability. The hybrid-mode Ćuk MII operates in unfolding-Type power conversion (UPC) mode during normal grid conditions and in two-stage power conversion (TPC) mode during grid faults. It also has the advantages of highly efficient power transfer and LVRT capability but is difficult to control because UPC and TPC modes have distinct system dynamics and suffer from grid voltage disturbances that have different magnitudes. To overcome this control problem, this article proposes a control strategy that corresponds to the operating mode of the hybrid-mode Ćuk inverter. To achieve zero steady-state tracking error during the grid disturbance, a repetitive controller (RC) is used in the proposed control scheme. Different phase-lead compensators in the RC compensate for different phase lags caused by distinct system dynamics. To reduce the burden from the RC, different nominal duty ratios are used as the feedforward control input. To minimize the tracking error during grid faults, a proportional-resonant controller is used in parallel with the RC controller in the TPC mode. To analyze the stability of different control systems, a unified control system model is presented for the proposed inverter. The procedure to select control parameters is also presented in detail. Simulation results validate the proposed control scheme in the hybrid-mode Ćuk inverter, and experiments are conducted using the 400-VA MII prototype to demonstrate its validity.

Original languageEnglish
Article number8845631
Pages (from-to)3917-3932
Number of pages16
JournalIEEE Journal of Emerging and Selected Topics in Power Electronics
Volume8
Issue number4
DOIs
StatePublished - Dec 2020

Keywords

  • Fault ride-Through
  • grid fault
  • module integrated inverter
  • proportional-resonant (PR) controller
  • reactive power transfer
  • repetitive controller (RC)

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