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The large-signal averaged model of a coupled-inductor double-boost converter is developed and analysed in this paper. Due to the large current fluctuations, the differential system is deduced by averaging the circuit equations of the operation modes over a switching period. Generic expressions that permit to calculate the current commutation intervals as function of the averaged state variables are also found to complete the model. Resistive losses are introduced into an equivalent averaged circuit leading to a more realistic scenario. The proposed state-space model is used for studying voltage conversion ratios, transients and frequency-domain responses of the converter as well as for designing a control loop that regulates the output voltage. Numerical simulations and experimental measurements corroborate the obtained results., Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales

The response of a digital Zero Average Dynamics ZAD-controlled buck converter under the variation of its intrinsic parameters as well as the pulse-width modulation signal is studied in detail. The multiparameter analysis presented here leads to a complete knowledge of the different dynamical scenarios exhibited by the system. Numerical results indicate that the success of the ZAD-strategy is highly dependent on the parameter and pulse-width modulation PWM combinations. Experiments are included to validate the performance inside the so-called optimum region. Copyright © 2013 John Wiley & Sons, Ltd.

Weed species present high competitive capacity, rapid adaptability and herbicide resistance, hindering their effective control across worldwide cropping regions. Since field-conducted experiments are very time-consuming and usually expensive, mathematical population-based models are valuable tools to test and develop long-term weed management programs. Within this context, the objective of this paper is to formalize analytically the possible seed bank dynamics of the Lolium rigidum, subjected to different control strategies. The first focus is on studying in detail the effects of integrating constant actions, promoting more environmentally and economically sustainable scenarios. From the same perspective, an alternative to applying time-variant programs is introduced. The proposed control guarantees that the weed population is sufficiently small or, alternatively, is kept below a given economic threshold level in a ten-year planning horizon. Furthermore, an optimization criterion is adopted for distributing necessary efficiency into diverse integrated options. Numerical simulations are included to illustrate the analytical findings. Fil: D'amico, Edith Maria Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina Fil: Calandrini, Guillermo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. Universidad Nacional del Sur. Departamento de Matemática; Argentina Fil: Gonzáles-Andujar, José Luis. Instituto de Agricultura Sostenible; España Fil: Chantre Balacca, Guillermo Ruben. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina

The first period-doubling bifurcation of a dc–dc buck converter controlled by a zero-average dynamic strategy is studied in detail. Owing to the saturation of the duty cycle, this bifurcation is followed by a border-collision bifurcation, which is the main mechanism to introduce instability and chaos in the circuit. The multiparameter analysis presented here leads to a complete knowledge of the relatioship between these two bifurcations. The results are obtained by using a frequency-domain approach for the study of period-two oscillations in maps. Copyright © 2010 John Wiley & Sons, Ltd. (The ∞-norm of a matrix A is defined as ∥A∥ = maxij|aij|. In particular, |aij|⩽∥A∥ for all i and j.)

Analytical solutions of the period-four orbits exhibited by a classical family of n-dimensionalquadratic maps are presented. Exact expressions are obtained by applying harmonic balance and Grobner bases to a single-input single-output representation of the system. A detailed study of a generalized scalar quadratic map and a well-known delayed logistic model is included for illustration. In the former example, conditions for the existence of bistability phenomenon are also introduced. Fil: D'amico, Edith Maria Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina Fil: Calandrini, Guillermo. Universidad Nacional del Sur. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación en Ingeniería Eléctrica; Argentina

A frequency domain methodology for the approximation of period doubling bifurcations in discrete-time nonlinear systems is presented. The computation of a stability index, which characterizes the dynamical behavior of the emerging period-two orbit is also derived. The technique is applied to estimate the domain of attraction of the fixed point in an adaptive control system and to improve the dynamical behavior of a buck converter.

A new network data transmission strategy was proposed in Zhang \& Chen [2005] (arXiv:1405.2404), where the resulting nonlinear system was analyzed and the effectiveness of the transmission strategy was demonstrated via simulations. In this paper, we further generalize the results of Zhang \& Chen [2005] in the following ways: 1) Construct first-return maps of the nonlinear systems formulated in Zhang \& Chen [2005] and derive several existence conditions of periodic orbits and study their properties. 2) Formulate the new system as a hybrid system, which will ease the succeeding analysis. 3) Prove that this type of hybrid systems is not structurally stable based on phase transition which can be applied to higher-dimensional cases effortlessly. 4) Simulate a higher-dimensional model with emphasis on their rich dynamics. 5) Study a class of continuous-time hybrid systems as the counterparts of the discrete-time systems discussed above. 6) Propose new controller design methods based on this network data transmission strategy to improve the performance of each individual system and the whole network. We hope that this research and the problems posed here will rouse interests of researchers in such fields as control, dynamical systems and numerical analysis., 40 pages, 19 figures

The application of the Hopf bifurcation theorem (HBT) for maps is presented in this paper. The invariant cycle emerging from the bifurcation is approximated using an analogous version of the graphical Hopf theorem (GHT) for continuous-time systems. This technique is formulated in the so-called frequency domain and it involves the use of the Nyquist stability criterion for discrete-time systems. An application example is included for illustration.