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This article presents a simple and systematic approach to synthesize a robust adaptive fuzzy fractional-order nonsingular terminal sliding mode controller (AFFO-NTSMC) to improve the output voltage tracking control performance of the dc–dc buck converters. The hybrid control method of fractional-order (FO) calculus and NTSMC are combined to create a FO-NTSMC, in which a new FO nonsingular terminal sliding mode surface is established. The idea behind this strategy is the increased flexibility achieved by FO calculation, improving robustness to disturbances and parameters variations provided by the traditional sliding mode controllers as well as finite time convergence properties of the output voltage error to the equilibrium point during the output load changes, simultaneously. In addition, a fuzzy logic system with online adaptive learning algorithm is designed to provide smooth chattering in switching control signal. The stability of the closed-loop system is carefully demonstrated by Lyapunov's theorem. Experimental measurements from a laboratory prototype are presented to demonstrate the effectiveness of the proposed AFFO-NSTSMC algorithm. [ABSTRACT FROM AUTHOR] more...

This paper describes the design of an interleaved sliding mode control for a multiphase synchronous buck converter, which inherits the properties of sliding mode control, operates with fixed switching frequency in the steady-state, and ensures current equalization among phases. Moreover, a power management algorithm is added in order to decide the number of active phases as function of the power load demand, thus optimizing the converter efficiency. The system uses a Master–Slave structure where each phase can actuate as the Master one in such a way that the overall system reliability is improved. Experimental results in a 1.5 kW eight-phase synchronous buck converter show that interleaving operation, robust output voltage regulation, phase current equalization, switching frequency regulation, and power management are achieved. [ABSTRACT FROM PUBLISHER] more...