Title: Stability analysis of parallel DC-DC converters controlled over communication network

Authors: Ashraf Khalil; Ang Swee Peng; Ali Asheibi

Addresses: Electrical and Electronic Engineering Department, Faculty of Engineering, Universiti Teknologi Brunei, Jalan Tungku Link Gadong BE1410, Darussalam, Brunei ' Electrical and Electronic Engineering Department, Faculty of Engineering, Universiti Teknologi Brunei, Jalan Tungku Link Gadong BE1410, Darussalam, Brunei ' Electrical and Electronic Engineering Department, Faculty of Engineering, University of Benghazi, Benghazi, Libya

Abstract: In this paper, we propose a method for computing the delay margin of parallel DC-DC converters controlled over communication network. The parallel converters implement master-slave control strategy where the control signals are exchanged over communication network. The system is modelled as a general time delay system and the delay margin required for system stability is computed. The transcendental characteristics equation is transformed to frequency dependent equation. The spectral radius is used to find the frequencies at which the roots cross the imaginary axis. The crossing frequencies are determined through the sweeping test and the binary iteration algorithm. The impact of the system and the controller parameters on the maximum delay margin is studied. It is found that the capacitance, the load resistance and the input voltage have strong effects on the delay margin, while for the controller parameters, the delay margin decreases with increasing the master voltage controller gain.

Keywords: communication delay; delay margin; parallel DC-DC converters; stability; sweeping test.

DOI: 10.1504/IJPELEC.2021.118522

International Journal of Power Electronics, 2021 Vol.14 No.4, pp.501 - 528

Received: 10 Jan 2019
Accepted: 31 Aug 2019

Published online: 18 Oct 2021 *

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