Arbitrary Fixed-Time Sliding Mode Control for Buck Converter with Matched and Mismatched Disturbances Based on Fixed-Time Observer

Kaplan O., Bodur F., Özdemir M. B.

IEEE ACCESS, cilt.13, ss.4582-4596, 2025 (SCI-Expanded)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 13
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1109/access.2024.3525092
  • Dergi Adı: IEEE ACCESS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Directory of Open Access Journals
  • Sayfa Sayıları: ss.4582-4596
  • Gazi Üniversitesi Adresli: Evet

Özet

This article introduces an arbitrary fixed-time sliding mode controller based on the fixed-time

disturbance observer (FxDO-FxSMC) for a buck converter with disturbance. FxDO-FxSMC is proposed to

address the issues of finite time convergence and large initial conditions present in existing sliding mode

controllers. FxDO-FxSMC uses an arbitrary sliding surface to stabilize the buck converter in the presence

of both matched and mismatched disturbances while ensuring arbitrary fixed-time convergence. First, the

buck converter’s modified state-space model, which contains both matched and mismatched disturbances, is

defined. Secondly, an arbitrary fixed-time disturbance observer is designed to predict disturbances. Finally,

an arbitrary FXSMC is constructed by defining the sliding surface with an arbitrary term and estimated

mismatched disturbance. The FxDO-FxSMC method (i) tackles an arbitrary fixed time sliding surface for

the buck converter with mismatched disturbance, a feature not achievable with the current finite/fixed

time sliding mode control; (ii) allows the user to adjust the convergence time of the proposed method,

regardless of the initial conditions; and (iii) concurrently mitigates chattering issues. Additionally, Lyapunov

stability is carried out. To highlight the advantages of the proposed combined structure, it is compared

with the classical SMC, integral SMC (ISMC), disturbance observer-based SMC (DO-SMC), and finitetime disturbance observer-based non-singular terminal SMC (FnDO-NTSMC). As a result of the simulation

tests, the chattering rate value (CRV) has been enhanced by 36.19% according to FnDO-NTSMC, which

provided the best response compared to other traditional techniques. The simulation results demonstrate

that the proposed controller effectively reduces overshoot, steady state error, and response time compared to

traditional and other controllers. We evaluated system performance using dynamic response MSE, RMSE,

and MAE for fair comparison. DO-SMC outperformed existing approaches in RMSE and MAE; however,

the proposed controller improved 174.27% and 99.26%. The simulation results prove that the proposed

controller design exhibits more rapid convergence and dynamic response to disturbances, regardless of initial

conditions.