Title: LMI based stability analysis of non-linearly perturbed DC motor speed control system with constant and time-varying delays

Authors: V. Venkatachalam; D. Prabhakaran; M. Thirumarimurugan; K. Ramakrishnan

Addresses: Department of Chemical Engineering, Coimbatore Institute of Technology, Coimbatore – 641014, Tamil Nadu, India ' Department of Chemical Engineering, Coimbatore Institute of Technology, Coimbatore – 641014, Tamil Nadu, India ' Department of Chemical Engineering, Coimbatore Institute of Technology, Coimbatore – 641014, Tamil Nadu, India ' Department of Electrical and Electronics Engineering, Pondicherry Engineering College, Pondicherry – 605014, India

Abstract: This research work describes the time-delays effect on speed control of DC motor system with non-linear load disturbance in the states. With this task, the paper presents a linearised model of speed control system based on delay-dependent state equation. Since the non-linearly load disturbance in the DC motor system (with time delay) ultimately affects the evolution of the system states, the non-linear load disturbance is modelled (mathematical) as a non-bounded non-linear function of current state vector and delayed state vector, subsequently included into the system stability analyses. In the analysis, two cases are employed: constant time delay and time-varying delay with exogenous load disturbance. In the proposed results, for broad range of PI controller gains, the maximum value of upper bound delay of DC motor speed control system are determined and new stability criterion was identified.

Keywords: DC motor speed control; delay-dependent stability; LMIs; linear matrix inequalities; Lyapunov-Krasovskii functional technique; NCSs; network control systems; non-linear-load perturbations; time delays.

DOI: 10.1504/IJPELEC.2019.096799

International Journal of Power Electronics, 2019 Vol.10 No.1/2, pp.1 - 17

Received: 25 May 2017
Accepted: 17 Jul 2017
Published online: 11 Dec 2018 *

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