Departing from analyzing a general input-saturated second-order system, a Lyapunov-based constructive procedure for the output-feedback stabilization of the constantly perturbed DC-DC buck power converter is presented. The proposed scheme also incorporates a Σ-Δ modulator. The obtained control scheme is developed in two parts: a proportional-integral-type family of algorithms devoted to regulating the uncertain system by using measurements of the output voltage and a Σ-Δ modulator dedicated to transforming the control action into a {0, 1} discrete-valued signal. This modulator is a kind of a sliding controller, which can be seen as a subsystem with an on-off output. This combination, the PI-type family of controllers and the Σ-Δ modulator, assures the global stability of the closed-loop system, even if parametric uncertainties are presented. The convergence analysis was carried out using Lyapunov's method. The theoretical results are confirmed using real-time experimental tests, which demonstrate the anti-windup scheme and the Σ-Δ modulator efficiency. The experiments consider the saturation of the control input and disturbances, having obtained convincing results.

The full-information state feedback controller is usually used for regulating the output voltage of converters. Sufficient sensors should be adopted to measure all of the states. However, the extensive use of current sensors not only increases the cost of the overall system, but also affects the reliability. In this paper, the sensorless control problem of DC–DC boost converters is addressed to avoid the need for the current sensor. First, a PI passivity-based control (PI-PBC) is proposed to stabilize this converter. The main feature of this design is that the exponential convergence of the system is guaranteed. Afterward, a generalized parameter estimation-based observer (GPEBO) is presented to estimate the inductor current with the finite-time convergence (FTC). By adding this estimate in the above PI-PBC, a sensorless controller is developed. Thanks to this FTC, the exponential convergence of an overall closed-loop system is ensured. Finally, the simulation and experimental results are given to assess the performance of the proposed controller.

This letter presents a novel anti-windup adaptive PID controller for trajectory tracking in input-constrained DC-DC buck converters supplying resistive and current loads under parametric uncertainty. The proposed control scheme extends the classical PID architecture by incorporating nonlinear integral action, an adaptive law for online parameter estimation, and a back-calculation-based anti-windup mechanism to address actuator saturation. A Lyapunov-based design framework is employed to establish global asymptotic stability, even in the presence of time-varying references and saturation constraints. Notably, anti-windup strategies grounded in Lyapunov theory for time-varying nonlinear systems are seldom available, making this contribution a significant advancement. Experimental validation on a laboratory buck converter confirms improved tracking accuracy and transient performance compared to conventional PID control, particularly under aggressive parameter variations and saturation-induced nonlinearities.

In this manuscript, the regulation of one degree-of-freedom Euler–Lagrange systems subject to input saturation is addressed. In particular, the design and analysis of a nonlinear static state feedback controller is presented. As a result, it is proven via Lyapunov's direct method that, in the presence of Rayleigh dissipation, the closed-loop equilibrium point is globally asymptotically stable with a strict Lyapunov function. Since saturation occurs in the system which contains the actuator model, the proposed control law is unconstrained and can be simplified to a proportional-derivative with desired gravity compensation algorithm. As a by-product global asymptotic stability is also proven for the case where Rayleigh dissipation is null. Numerical simulations on a crank-slider mechanism are presented. Moreover, experimental results on a DC-DC buck power converter are also shown and confirm the viability of our approach.

Trajectory tracking in dc–dc buck converters is critical for applications requiring precise and dynamic voltage control. Integral-action controllers, commonly used for voltage regulation and trajectory tracking, often fail to account for input constraints, leading to integrator windup and potential instability. To address these challenges, we propose a novel adaptive nonlinear proportional-derivative plus limited integrator anti-windup (PD+LIAW) controller, which, to the best of our knowledge, represents the first solution to integrator windup in trajectory tracking for buck converters. The proposed controller ensures precise tracking of time-varying References, effectively mitigates integrator windup, and delivers robust performance under input saturation and parameter variations. To the best of our knowledge, this work presents the first rigorous Lyapunov-based stability analysis of the LIAW method for trajectory tracking, incorporating adaptation to parameter uncertainties. The experimental results demonstrate the superior performance of the proposed algorithm compared to conventional linear proportional–integral–derivative (PID) controllers and state-of-the-art methods, showcasing improved trajectory tracking, enhanced robustness, and effective mitigation of windup-induced instabilities.