For a large class of relay feedback systems (RFS) there will be limit cycle oscillations. Conditions to check existence and local stability cycles for these are well known. Global conditions, however, practically nonexistent. The paper presents conditions in the form linear matrix inequalities (LMIs) that, when satisfied, guarantee global asymptotic induced by relays with hysteresis time-invariant (LTI) stable systems. analysis consists finding quadratic surface Lyapunov functions Poincare...

Due to the demand for high reliability, modular multilevel converters (MMCs) are designed with redundant submodules. Redundant submodules can be integrated into converter by employing different redundancy schemes: conventional active scheme, load-sharing and passive scheme. Different schemes have impacts on improvement of reliability. The contributions this paper include that an analytical method is proposed evaluate reliability MMCs under factors' influence analyzed determine proper...

In modular multilevel converters (MMCs), temperature control of semiconductor devices in the submodules (SMs) is a key factor for safe and reliable operation. Under normal operation, significant differences can exist between SMs due to, example, aging modules module parameter mismatch. This paper presents method achieving SM thermal balancing by controlling capacitor voltage each an arm, while maintaining sum voltages at constant value order to regulate dc-link voltage. The proposed strategy...

In this study, we consider an unknown discrete-time, linear time-invariant, autonomous system and characterise, the minimal number of discrete-time steps necessary to compute asymptotic final value a state. The results presented in paper have direct link with celebrated theorem. We apply these design algorithm for minimal-time distributed consensus illustrate on example.

This paper is concerned with global asymptotic output synchronization in networks of identical feedback systems. Using an operator theoretic approach based on incremental small gain theorem, the method reformulates problem as one achieving stability using a coupling that plays role incrementally stabilizing feedback. In this way, conditions static or dynamic operators achieve nodes arbitrary structure are derived. These lead to methodology for construction architectures ensure wide range The...

For a large class of relay feedback systems (RFS) there will be limit cycle oscillations. Conditions to check existence and local stability cycles for these are well known. Global conditions, however, practically non-existent. The paper presents conditions in the form linear matrix inequalities (LMIs) that guarantee global asymptotic induced by with hysteresis an LTI stable system. analysis is based on finding quadratic Lyapunov functions Poincare map associated RFS. We found typical flow...

This paper considers quadratic surface Lyapunov functions in the study of global stability analysis on/off systems (OFS), including those OFS with unstable nonlinearity sectors. In previous work, were successfully applied to prove asymptotic limit cycles relay feedback systems. this we show that these ideas can be used equilibrium points piecewise linear (PLS). We present conditions form LMI that, when satisfied, guarantee an point. A large number examples was proven globally stable. These...

This work presents a sum-of-squares method to construct polynomial surface Lyapunov functions (SuLF) of arbitrary order for the impact maps limit cycles in piecewise linear systems (PLS). extends previous results on stability analysis such cycles, which utilized quadratic SuLFs. paper also discusses an initial study hierarchical jump where switching is driven by feedback low-level dynamical system states and Markovian process.

The large-scale penetration of renewable generation into power systems has required an integration wind and conventional thermal generation. This been supported by high-voltage direct-current lines for bulk transmission as is normally located far away from the load centres. participation generators in primary frequency regulation stability become important challenge due to intermittent nature wind. especially relevant slow response and, therefore, coordination between these two sources...

This paper proposes the extension of current control loops used in Modular Multilevel Converters to include semiconductors junction temperature as an operational constraint. A new controller is added inner loop modulate limits a function temperature, providing power transmission capacity without violating thermal semiconductors. numerical method investigate operation converters with temperature-dependent proposed and stability analyzed validated through simulations under steady transient operations.

This note addresses identification of the $A$-matrix in continuous time linear dynamical systems on state-space form. If this matrix is partially known or to have a sparse structure, such knowledge can be used simplify identification. We begin by introducing some general conditions for solvability inverse problems exponential. Next, we introduce "system aliasing" as an issue slow sampled systems. Such aliasing give rise non-unique logarithms. As show, imposing additional and prior about...

This paper presents semi-global sufficient stability conditions of limit cycles for relay feedback systems. Local exist. These are based on analyzing the linear part Poincare map. We know that when a certain cycle satisfies those local conditions, neighborhood around exists such any trajectory starting in this converges to as time goes infinity. However, tools characterize do not In work, we present form matrix inequalities (LMI), guarantee reasonably large set it. results differ from...

This paper considers quadratic surface Lyapunov functions in the study of global asymptotic stability saturation systems (SAT), including those with unstable nonlinearity sectors. We show that can be applied to analyze piecewise linear more than one switching surface. For that, we consider SAT. present conditions form LMIs when satisfied, guarantee equilibrium points. A large number examples was successfully proven globally stable, high dimension and sectors, for which classical methods like...

This note uses quadratic surface Lyapunov functions (SuLFs) to efficiently check if a double integrator in feedback with saturation nonlinearity has L 2 -gain less than γ > 0. We show that for many such systems, the is nonconservative sense this approximately equal lower bound obtained by replacing constant gain of 1. These results allow use classical analysis tools like μ-analysis or integral constraints analyze systems integrators and saturations, including servo some mechanical...

Input-output stability results for feedback systems are developed. Robust conditions presented nonlinear with uncertainty defined by some function (with argument equal to the norm of input) that bounds its output norm. A sufficient small gain theorem a class these is presented. Then it also shown that, vector spaces (l/sub /spl infin//, par//spl middot//spl par//sub infin//) and 2/, 2/), necessary additional assumptions on systems. These capture conservatism as applied do not need have linear gain.