Open AccessDiscretisation performance analysis of sliding mode controlled DC–DC buck converter via zero‐order holder
Author(s) -
Wang Cong,
Xia Hongwei,
Wang Yanmin,
Mai Yongfeng,
Ren Shunqing
Publication year - 2019
Publication title -
iet control theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.059
H-Index - 108
eISSN - 1751-8652
pISSN - 1751-8644
DOI - 10.1049/iet-cta.2019.0067
Subject(s) - control theory (sociology) , discretization , controller (irrigation) , converters , stability (learning theory) , limit (mathematics) , buck converter , sliding mode control , exponential stability , computer science , mathematics , voltage , engineering , physics , nonlinear system , control (management) , mathematical analysis , electrical engineering , artificial intelligence , machine learning , quantum mechanics , agronomy , biology
This study investigates the discretisation effects of the zero‐order holder (ZOH) on DC–DC buck converters under the direct ON/OFF control of sliding mode (SM), and the two core issues of stability and periodicity for the discrete system are focused on. The optimal parameter for the SM controller is first given on the basis of stability and response speed in the continuous‐time domain, following its ZOH discretisation. Restricted by the existence condition of discrete SM, the guaranteed stability is investigated and compared with that of the continuous system in the phase plane, proving that the sampling time of ZOH affects its stability region. Meanwhile, the periodic dynamics, including the system state and the symbolic sequence of switching control law, is further studied via analysing the steady limit cycle of state in phase plane; and the existence condition of multi‐periodicity is also deduced. Innovatively this study establishes the influence relationship of the periodic dynamics with the performances of the steady‐state error of output voltage and switching frequency. Simulation and experiment results are presented to validate the theoretical and practical value of the proposed research.