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Copyright of Flora Montibérica is the property of Flora Montiberica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Flora Montibérica is the property of Flora Montiberica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Located in the High-Speed Railway Line Madrid-Extremadura, the bridge has a total length of 1488m. The span distribution is influenced by the crossing of the Tajo River, which takes place with an arch, 324m long, and dividing the deck over it in six spans of 54m each one. The approach spans are 60m long, inserting two transition spans of 57m. The emblematic element of the bridge is aforementioned arch. With curve directrix, it is formed by a hollow variable section between (4.00 m - 3.50 m wide; 12.00 m - 6.00 m high). With its man span length of 324m, it will surpass the bridge over the Contreras Reservoir, currently the largest railway arch bridge executed in Spain. [ABSTRACT FROM AUTHOR]

The Basarab cable-stayed bridge is part of the Basarab Flyover Bypass in Bucharest, and consists of a road, a tramway and a multimodal station. The main span is 168 m supported by one pylon. The main span holds a covered tramway station. The fact that the bridge crosses over the tracks from Basarab Railway Station was critical in the construction of the deck. The most demanding action for the bridge was the seismic load requiring the use of an innovative combination of seismic isolation devices: viscoelastic damping devices located both at the main tower and at the main abutment and hysteretic devices on the ramp abutments. [ABSTRACT FROM AUTHOR]

Multilevel converters are nowadays an enabling key in the integration of electric power into the grid as they introduce less distortion and, thus, they are more compliant with the grid standards, among other benefits. A well-known topology is the three-level Neutral-Point-Clamped whose control requires to deal with the capacitors voltage unbalance. This paper presents a modulation approach where the injection of a common component in the modulated voltage is studied in order to achieve such voltage balance. An optimization problem that, apart from the voltage balance, aims the lowest number of commutations and can be solved very efficiently with up to five computations of the cost function is formulated. The main advantages of the proposed modulation strategy are its simplicity and its flexibility, since it is also valid for unbalanced grid conditions and, with little added complexity, for low (and even zero) power factor conditions. Simulation results under unbalanced grid conditions are provided in order to show its validity under this scenario. The strategy is evaluated and compared with a space-vector-based approach in an experimental setup, yielding similar total harmonic current distortion, a 30% reduction in the number of commutations, and better voltage balance performance for lower power factor conditions. • A modulation approach for capacitors balance in NPC converters is proposed. • The advantages are simplicity and validity for unbalanced-grid-voltage conditions. • The number of commutations is optimized. • An enhancement is proposed to work under low-power-factor conditions. • Experimental comparison with virtual space vector is performed. [ABSTRACT FROM AUTHOR]

This paper uses a novel approach for the control of three-level neutral-point-clamped (NPC) rectifiers in order to tackle the capacitor voltage balance problem. A distinctive feature of the new control approach is that it is based on a model which is written in terms of the duty ratios for each phase at each level. Hence, the system model presents nine duty cycle variables. Despite the fact that this formulation is different from the usual ones, it is shown that the control problem of currents and dc-link voltage can be formulated in a similar way to conventional methods. Furthermore, the control of the capacitor voltage balance can be expressed by means of equations that are decoupled from the currents and dc-link voltage dynamics, which results in a specific controller for the voltage balancing that does not affect the previous dynamics. A key point of the proposed approach is that part of the modulation stage is implicit in the formulation. Two particular controllers are compared in this paper. The first one fulfills the different control objectives at the expense of a large number of commutations. This problem is overcome in a new proposed controller, which presents similar performance and a satisfactory number of commutations. Experimental results are performed showing the effectiveness compared with a modified virtual space vector modulation with capacitor voltage balance capabilities. [ABSTRACT FROM AUTHOR]