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

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 mo...

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Main Authors: Orhan Kaplan, Ferhat Bodur, Mustafa Bahadir Ozdemir
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/10820343/
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author Orhan Kaplan
Ferhat Bodur
Mustafa Bahadir Ozdemir
author_facet Orhan Kaplan
Ferhat Bodur
Mustafa Bahadir Ozdemir
author_sort Orhan Kaplan
collection DOAJ
description 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 1) 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; 2) allows the user to adjust the convergence time of the proposed method, regardless of the initial conditions; and 3) 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 finite-time 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.
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issn 2169-3536
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spelling doaj-art-8124f69bb0614a78a66433e776627d612025-01-10T00:00:51ZengIEEEIEEE Access2169-35362025-01-01134582459610.1109/ACCESS.2024.352509210820343Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time ObserverOrhan Kaplan0https://orcid.org/0000-0003-0590-7106Ferhat Bodur1https://orcid.org/0000-0002-5748-1349Mustafa Bahadir Ozdemir2https://orcid.org/0000-0001-7801-9367Electrical Electronics Engineering, Faculty of Technology, Gazi University, Ankara, TürkiyeElectrical Electronics Engineering, Faculty of Technology, Gazi University, Ankara, TürkiyeEnergy Systems Engineering, Faculty of Technology, Gazi University, Ankara, TürkiyeThis 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 1) 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; 2) allows the user to adjust the convergence time of the proposed method, regardless of the initial conditions; and 3) 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 finite-time 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.https://ieeexplore.ieee.org/document/10820343/Arbitrary convergence timearbitrary time stabilitybuck converterfixed-time disturbance observerfixed-time sliding mode controlmatched-mismatched disturbance
spellingShingle Orhan Kaplan
Ferhat Bodur
Mustafa Bahadir Ozdemir
Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time Observer
IEEE Access
Arbitrary convergence time
arbitrary time stability
buck converter
fixed-time disturbance observer
fixed-time sliding mode control
matched-mismatched disturbance
title Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time Observer
title_full Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time Observer
title_fullStr Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time Observer
title_full_unstemmed Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time Observer
title_short Arbitrary Fixed-Time Sliding Mode Control for Buck Converter With Matched and Mismatched Disturbances Based on Fixed-Time Observer
title_sort arbitrary fixed time sliding mode control for buck converter with matched and mismatched disturbances based on fixed time observer
topic Arbitrary convergence time
arbitrary time stability
buck converter
fixed-time disturbance observer
fixed-time sliding mode control
matched-mismatched disturbance
url https://ieeexplore.ieee.org/document/10820343/
work_keys_str_mv AT orhankaplan arbitraryfixedtimeslidingmodecontrolforbuckconverterwithmatchedandmismatcheddisturbancesbasedonfixedtimeobserver
AT ferhatbodur arbitraryfixedtimeslidingmodecontrolforbuckconverterwithmatchedandmismatcheddisturbancesbasedonfixedtimeobserver
AT mustafabahadirozdemir arbitraryfixedtimeslidingmodecontrolforbuckconverterwithmatchedandmismatcheddisturbancesbasedonfixedtimeobserver