Impedance-based local stability criterion for DC distributed power systems

Xin Zhang, Xinbo Ruan, Chi Kong Tse

Research output: Journal article publicationJournal articleAcademic researchpeer-review

181 Citations (Scopus)


This paper addresses the stability issue of dc distributed power systems (DPS). Impedance-based methods are effective for stability assessment of voltage-source systems and current-source systems. However, these methods may not be suitable for applications involving variation of practical parameters, loading conditions, system's structures, and operating modes. Thus, for systems that do not resemble simple voltage-source systems or current-source systems, stability assessment is much less readily performed. This paper proposes an impedance-based criterion for stability assessment of dc DPS. We first classify any converter in a dc DPS as either a bus voltage controlled converter (BVCC) or a bus current controlled converter (BCCC). As a result, a dc DPS can be represented in a general form regardless of its structure and operating mode. Then, the minor loop gain of the standard dc DPS is derived precisely using a two-port small signal model. Application of the Nyquist criterion on the derived minor loop gain gives the stability requirement for the dc DPS. This proposed criterion is applicable to dc DPSs, regardless of the control method and the connection configuration. Finally, a 480 W photovoltaic (PV) system with battery energy storage and a 200 W dc DPS, in which the source converter employs a droop control, are fabricated to validate the effectiveness of the proposed criterion.
Original languageEnglish
Article number7004887
Pages (from-to)916-925
Number of pages10
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Issue number3
Publication statusPublished - 1 Mar 2015


  • Battery energy storage
  • DC distributed power system (DPS)
  • photovoltaic system
  • stability criterion

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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