Active input-voltage and load-current sharing in input-series and output-parallel connected modular dc-dc converters using dynamic input-voltage reference scheme

Raja Ayyanar, Ramesh Giri, Ned Mohan

Research output: Contribution to journalArticlepeer-review

337 Scopus citations

Abstract

This paper explores a new configuration for modular dc-dc converters, namely, series connection at the input, and parallel connection at the output, such that the converters share the input voltage and load current equally. This is an important step toward realizing a truly modular power system architecture, where low-power, low-voltage, building block modules can be connected in any series/parallel combination at input or at output, to realize any given system specifications. A three-loop control scheme, consisting of a common output voltage loop, individual inner current loops, and individual input voltage loops, is proposed to achieve input voltage and load current sharing. The output voltage loop provides the basic reference for inner current loops, which is modified by the respective input voltage loops. The average of converter input voltages, which is dynamically varying, is chosen as the reference for input voltage loops. This choice of reference eliminates interaction among different control loops. The input-series and output-parallel (ISOP) configuration is analyzed using the incremental negative resistance model of dc-dc converters. Based on the analysis, design methods for input voltage controller are developed. Analysis and proposed design methods are verified through simulation, and experimentally, on an ISOP system consisting of two forward converters.

Original languageEnglish (US)
Pages (from-to)1462-1473
Number of pages12
JournalIEEE Transactions on Power Electronics
Volume19
Issue number6
DOIs
StatePublished - Nov 2004

Bibliographical note

Funding Information:
Manuscript received August 26, 2003; revised February 4, 2004. This work was supported by the Office of Naval Research (ONR) under Award N00014-00-1-0928 and Award N00014-03-1-0802. Recommended by Associate Editor P. M. Barbosa. R. Ayyanar is with the Department of Electrical Engineering, Arizona State University, Tempe, AZ 85287–5706 USA. R. Giri is with Maxim Integrated Products, Sunnyvale, CA 94086 USA. N. Mohan is with the University of Minnesota, Minneapolis, MN 55455 USA. Digital Object Identifier 10.1109/TPEL.2004.836671

Keywords

  • Input-series and output-parallel (ISOP)
  • Input-series connection
  • Load sharing
  • Modular converter
  • Voltage sharing

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