Variable-Switching-Frequency State-Feedback Control of a Phase-Shifted Full-Bridge DC/DC Converter

Ayan Mallik, Alireza Khaligh

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


This paper presents a methodology to control a phase-shifted full-bridge (PSFB) dc/dc converter with variable switching frequency, as a function of the output load power. The main objective of such control is to maximize the conversion efficiency at a wide range of load power levels. By tuning the switching frequency, the net phase of the input impedance of the converter can be manipulated, and thus, at the lower load power operation, the net input impedance can be made highly inductive to achieve zero-voltage switching (ZVS) at the primary-side switches. This paper proposes an efficiency maximization method, which derives an optimum switching frequency based on the load power from a loss-minimization model. In addition, a state-feedback-based control method is proposed for maintaining a tight dynamic regulation over the converter output under a load transient. A 6-kW laboratory prototype of the PSFB converter is developed and designed to validate the proposed control algorithm. The experimental results show a conversion efficiency of 98% at full load and output voltage ripple of ±1%, while ensuring ZVS at all operating points between 100 W and 6 kW.

Original languageEnglish (US)
Article number7586135
Pages (from-to)6523-6531
Number of pages9
JournalIEEE Transactions on Power Electronics
Issue number8
StatePublished - Aug 2017
Externally publishedYes


  • Phase shift
  • State-feedback control
  • Variable frequency
  • Zero-voltage switching (ZVS)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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