Control and Modulation of Bidirectional Single-Phase AC-DC Three-Phase-Leg SPWM Converters with Active Power Decoupling and Minimal Storage Capacitance

Hao Wu, Siu Chung Wong, Chi Kong Tse, Qianhong Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

37 Citations (Scopus)


In a single-phase grid-connected nanogrid system, a bidirectional ac-dc converter is usually required to transfer energy between the ac grid and a dc bus. Active ac power balancing is often implemented to prevent the ac grid ripple power from injecting into the dc bus. A four-phase-leg sinusoidal pulsewidth-modulation (SPWM) converter can readily provide power factor correction and active ac power balancing. In this paper, the use of three-phase-leg SPWM converters for achieving these functions is analyzed. A family of bidirectional single-phase ac-dc three-phase-leg SPWM converters with an ac storage capacitor for use in a nanogrid system is designed with a general control structure and a modulation scheme for minimizing the ac storage capacitance. The general control structure is designed to achieve a decoupled system of a power-factor-correction converter cascaded with an active ac power load at the dc bus. The decoupled system is developed based on decomposition to differential-mode and common-mode voltages. The modulation method involves an extra zero-sequence voltage injection derived from the three-phase-leg SPWM voltages without introducing higher order harmonic distortions. A significant reduction of the ac storage capacitance and an improvement of converter efficiency are achieved. The design and analysis are verified by simulations and experimental measurements.
Original languageEnglish
Article number7247724
Pages (from-to)4226-4240
Number of pages15
JournalIEEE Transactions on Power Electronics
Issue number6
Publication statusPublished - 1 Jun 2016


  • AC storage capacitor
  • AC-DC bus converter
  • DC bus LED lighting
  • single-phase inverter
  • single-phase rectifier

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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