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SUMMARY This paper addresses the imbalance problem of the dc-link capacitor voltages in the three-level diode-clamped back-to-back power converter. In order to cope with it, a mathematical analysis of the capacitor voltage difference dynamics, based on a continuous model of the converter, is first carried out. It leads to an approximated model that contains explicitly several sinusoidal functions of time. In view of this result, the voltage imbalance phenomenon can be addressed as an output regulation problem, considering the sinusoidal functions of time as exogenous disturbances. Thus, a novel approach to deal with the mentioned problem in the back-to-back converter is presented. Then, the particular features of the disturbances are used to design several controllers. They all follow an asymptotic disturbance rejection approach. In this way, the estimates of the disturbances are used to apply a control law that cancels them while regulating the capacitor voltage balance as well. Finally, the performance of the proposed control laws is evaluated, presenting the simulation results obtained when the different controllers are implemented. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: This article focuses on the design of a robust switching control law for uncertain switched affine systems in the discrete‐time domain. More precisely, a novel control law is introduced whose parameters result from an optimization problem, aiming at reducing the volume of the attractive and invariant set, where the solutions to the closed‐loop system converge to. The design is based on a quadratic Lyapunov function and guarantees global practical stabilization, that is, global stabilization in a neighborhood of a desired operating point and robustness with respect to model uncertainties. Our method and the associated relaxed control law are then compared with existing conditions from the literature and are validated through numerical examples. [ABSTRACT FROM AUTHOR]