ACES  Control Avançat de Sistemes d'Energia
http://hdl.handle.net/2117/114
20180221T03:58:17Z

Optimal power flow for resistive DC networks: a porthamiltonian approach
http://hdl.handle.net/2117/112298
Optimal power flow for resistive DC networks: a porthamiltonian approach
Benedito Benet, Ernest; del Puerto Flores, Dunstano; Dòria Cerezo, Arnau; Scherpen, Jacquelien
This paper studies the optimal power flow problem for resistive DC networks. The gradient method algorithm is written in a portHamiltonian form and the stability of the resulting dynamics is studied. Stability conditions are provided for general cyclic networks and a solution, when these conditions fail, is proposed. In addition, the results are exemplified by means of numerical simulations.
20171220T08:08:27Z
Benedito Benet, Ernest
del Puerto Flores, Dunstano
Dòria Cerezo, Arnau
Scherpen, Jacquelien
This paper studies the optimal power flow problem for resistive DC networks. The gradient method algorithm is written in a portHamiltonian form and the stability of the resulting dynamics is studied. Stability conditions are provided for general cyclic networks and a solution, when these conditions fail, is proposed. In addition, the results are exemplified by means of numerical simulations.

An Interactive and comprehensive software tool to promote active learning in the Loop Shaping Control System design
http://hdl.handle.net/2117/111884
An Interactive and comprehensive software tool to promote active learning in the Loop Shaping Control System design
Díaz, José Manuel; Costa Castelló, Ramon; Muñoz, R; Dormido Bencomo, Sebastián
The classical loop shaping is a design procedure that explicitly involves the shaping of the open loop transfer function L(s), within a desired frequency spectrum by manipulating the poles, zeros, and gain of the controller C(s). Interactive software tools have proven as, particularly, useful techniques with high impact on control education. This kind of interactive tools has demonstrated in the past that students learn in a much more active way. This paper presents the basic functionality of the linear control system design (LCSD), an interactive tool for analysis and design of linear control systems with special emphasis on the classical loop shaping design. The software tool is implemented in Sysquake, a MATLABlike language with fast execution and excellent facilities for interactive graphics, and is delivered as a standalone executable that is readily accessible to students and instructors. Several design problems are used to illustrate the main features of the LCSD tool to perform classical loop shaping.
20171213T12:07:31Z
Díaz, José Manuel
Costa Castelló, Ramon
Muñoz, R
Dormido Bencomo, Sebastián
The classical loop shaping is a design procedure that explicitly involves the shaping of the open loop transfer function L(s), within a desired frequency spectrum by manipulating the poles, zeros, and gain of the controller C(s). Interactive software tools have proven as, particularly, useful techniques with high impact on control education. This kind of interactive tools has demonstrated in the past that students learn in a much more active way. This paper presents the basic functionality of the linear control system design (LCSD), an interactive tool for analysis and design of linear control systems with special emphasis on the classical loop shaping design. The software tool is implemented in Sysquake, a MATLABlike language with fast execution and excellent facilities for interactive graphics, and is delivered as a standalone executable that is readily accessible to students and instructors. Several design problems are used to illustrate the main features of the LCSD tool to perform classical loop shaping.

A new approach for flux and rotor resistance estimation of induction motors
http://hdl.handle.net/2117/111323
A new approach for flux and rotor resistance estimation of induction motors
Bazylev, Dmitry; Dòria Cerezo, Arnau; Pyrkin, Anton A.; Bobstov, Alexey A.; Ortega, Romeo
In this paper we address the problems of flux and rotor resistance estimation of induction motors. We propose a radically new approach that combines the recently introduced techniques of parameter estimation based observers (PEBO) with the dynamic regression extension and mixing (DREM) parameter adaptation. The PEBO framework is used to recast the flux observation task as a parameter estimation problem, for which the DREM technique is utilised. The resulting flux observer is then combined with a standard gradient estimator for the rotor resistance. Simulation results of an adaptive implementation of the classical field oriented controller demonstrate the effectiveness of the proposed flux observer and rotor resistance estimator even in closedloop operation.
20171129T10:47:16Z
Bazylev, Dmitry
Dòria Cerezo, Arnau
Pyrkin, Anton A.
Bobstov, Alexey A.
Ortega, Romeo
In this paper we address the problems of flux and rotor resistance estimation of induction motors. We propose a radically new approach that combines the recently introduced techniques of parameter estimation based observers (PEBO) with the dynamic regression extension and mixing (DREM) parameter adaptation. The PEBO framework is used to recast the flux observation task as a parameter estimation problem, for which the DREM technique is utilised. The resulting flux observer is then combined with a standard gradient estimator for the rotor resistance. Simulation results of an adaptive implementation of the classical field oriented controller demonstrate the effectiveness of the proposed flux observer and rotor resistance estimator even in closedloop operation.

Control óptimo de par para máquinas SynRM aplicadas a vehículo eléctrico
http://hdl.handle.net/2117/111319
Control óptimo de par para máquinas SynRM aplicadas a vehículo eléctrico
Trancho, Elena; Ibarra Basabe, Edorta; Arias Pujol, Antoni; Kortabarria, Iñigo
Las máquinas de reluctancia síncrona asistidas por imanes están atrayendo un considerable interés como alternativa a las máquinas síncronas de imanes permanentes para su uso en sistemas de propulsión de vehículos eléctricos. El control óptimo de estas máquinas (incluyendo operación en debilitamiento de campo) puede resultar complejo, ya que estas son, por lo general, muy sensibles al fenómeno de la saturación magnética. En este artículo se trata su control, desde los reguladores hasta el precalculo de referencias de corriente óptimas para todo el rango de operación de la máquina. Finalmente, se muestran resultados experimentales obtenidos en una máquina de 51 kW.
20171129T09:34:18Z
Trancho, Elena
Ibarra Basabe, Edorta
Arias Pujol, Antoni
Kortabarria, Iñigo
Las máquinas de reluctancia síncrona asistidas por imanes están atrayendo un considerable interés como alternativa a las máquinas síncronas de imanes permanentes para su uso en sistemas de propulsión de vehículos eléctricos. El control óptimo de estas máquinas (incluyendo operación en debilitamiento de campo) puede resultar complejo, ya que estas son, por lo general, muy sensibles al fenómeno de la saturación magnética. En este artículo se trata su control, desde los reguladores hasta el precalculo de referencias de corriente óptimas para todo el rango de operación de la máquina. Finalmente, se muestran resultados experimentales obtenidos en una máquina de 51 kW.

On average real sliding dynamics in linear systems
http://hdl.handle.net/2117/110940
On average real sliding dynamics in linear systems
Olm Miras, Josep Maria; Biel Solé, Domingo; Repecho del Corral, Víctor; Shtessel, Yuri B.
It is well known that in implementations of sliding mode controllers using hysteresis comparators, when the hysteresis band amplitude tends to zero the real dynamics tends to the ideal sliding dynamics. However, in real systems physical limitations do not allow to effectively lower this value at will, and a steady state error is likely to appear. In this paper we relate this error with a non zero average value of the switching function in each switching period: it is shown that, in linear systems, when the controller has a constant switching frequency and the switching function is periodic, the average value of the difference between real and ideal steady state dynamics is proportional to the average value of the switching function. Hence, when this average value is non zero an average steady state error appears, while a zero average value for the switching function entails no average steady state error. The proof is carried out using a regular form approach, and the result is exemplified in a buck converter. Simulation results show that when the switching function is periodic and shows a piecewise linear behavior within the hysteresis band, thus guaranteeing zero average value, the average state error disappears. In turn, when this piecewise linear character is lost and the switching function has non zero mean value, an average steady state error arises.
20171120T16:33:09Z
Olm Miras, Josep Maria
Biel Solé, Domingo
Repecho del Corral, Víctor
Shtessel, Yuri B.
It is well known that in implementations of sliding mode controllers using hysteresis comparators, when the hysteresis band amplitude tends to zero the real dynamics tends to the ideal sliding dynamics. However, in real systems physical limitations do not allow to effectively lower this value at will, and a steady state error is likely to appear. In this paper we relate this error with a non zero average value of the switching function in each switching period: it is shown that, in linear systems, when the controller has a constant switching frequency and the switching function is periodic, the average value of the difference between real and ideal steady state dynamics is proportional to the average value of the switching function. Hence, when this average value is non zero an average steady state error appears, while a zero average value for the switching function entails no average steady state error. The proof is carried out using a regular form approach, and the result is exemplified in a buck converter. Simulation results show that when the switching function is periodic and shows a piecewise linear behavior within the hysteresis band, thus guaranteeing zero average value, the average state error disappears. In turn, when this piecewise linear character is lost and the switching function has non zero mean value, an average steady state error arises.

Identification of PEM fuel cells based on support vector regression and orthonormal bases
http://hdl.handle.net/2117/110513
Identification of PEM fuel cells based on support vector regression and orthonormal bases
Feroldi, Diego Hernan; Gómez, Juan Carlos; Roda Serrat, Vicente
Polymer Electrolyte Membrane Fuel Cells (PEMFC) are efficient devices that convert the chemical energy of the reactants in electricity. In this type of fuel cells, the performance of the air supply system is fundamental to improve their efficiency. An accurate mathematical model representing the air filling dynamics for a wide range of operating points is then necessary for control design and analysis. In this paper, a new Wiener model identification method based on Support Vector (SV) Regression and orthonormal bases is introduced and used to estimate a nonlinear dynamical model for the air supply system of a laboratory PEMFC from experimental data. The method is experimentally validated using a PEMFC system based on a ZB 8cell stack with Nafion 115 membrane electrode assemblies
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20171113T17:22:39Z
Feroldi, Diego Hernan
Gómez, Juan Carlos
Roda Serrat, Vicente
Polymer Electrolyte Membrane Fuel Cells (PEMFC) are efficient devices that convert the chemical energy of the reactants in electricity. In this type of fuel cells, the performance of the air supply system is fundamental to improve their efficiency. An accurate mathematical model representing the air filling dynamics for a wide range of operating points is then necessary for control design and analysis. In this paper, a new Wiener model identification method based on Support Vector (SV) Regression and orthonormal bases is introduced and used to estimate a nonlinear dynamical model for the air supply system of a laboratory PEMFC from experimental data. The method is experimentally validated using a PEMFC system based on a ZB 8cell stack with Nafion 115 membrane electrode assemblies

Combined heat and power using high temperature proton exchange membrane fuel cells for comfort applications
http://hdl.handle.net/2117/110267
Combined heat and power using high temperature proton exchange membrane fuel cells for comfort applications
Sanz i López, Víctor; Costa Castelló, Ramon; Batlle Arnau, Carles
Global concerns about nowadays’ energy shortage problems as well as climate change eects have encouraged alternatives to classical energy sources such as fossil fuels and nuclear power plants. In this context, combined heat and power is presented as a useful option due to its ability of generating both electrical and thermal energy more eciently than conventional methods. Regarding this, high temperature proton exchange membrane fuel cells are not only a reliable way of implementing combined heat and power systems, but also a better solution in terms of energy conversion eciency and greenhouse gases emissions reduction. Therefore, high temperature proton exchange membrane fuel cells are being installed around the world and policies encouraging its utilisation are being promoted.
20171110T13:00:50Z
Sanz i López, Víctor
Costa Castelló, Ramon
Batlle Arnau, Carles
Global concerns about nowadays’ energy shortage problems as well as climate change eects have encouraged alternatives to classical energy sources such as fossil fuels and nuclear power plants. In this context, combined heat and power is presented as a useful option due to its ability of generating both electrical and thermal energy more eciently than conventional methods. Regarding this, high temperature proton exchange membrane fuel cells are not only a reliable way of implementing combined heat and power systems, but also a better solution in terms of energy conversion eciency and greenhouse gases emissions reduction. Therefore, high temperature proton exchange membrane fuel cells are being installed around the world and policies encouraging its utilisation are being promoted.

Optimal power flow for resistive DC networks: a porthamiltonian approach
http://hdl.handle.net/2117/110148
Optimal power flow for resistive DC networks: a porthamiltonian approach
Benedito Benet, Ernest; del Puerto Flores, Dunstano; Dòria Cerezo, Arnau; Scherpen, Jacquelien
This paper studies the optimal power flow problem for resistive DC networks. The gradient method algorithm is written in a portHamiltonian form and the stability of the resulting dynamics is studied. Stability conditions are provided for general cyclic networks and a solution, when these conditions fail, is proposed. In addition, the results are exemplified by means of numerical simulations.
20171108T13:10:59Z
Benedito Benet, Ernest
del Puerto Flores, Dunstano
Dòria Cerezo, Arnau
Scherpen, Jacquelien
This paper studies the optimal power flow problem for resistive DC networks. The gradient method algorithm is written in a portHamiltonian form and the stability of the resulting dynamics is studied. Stability conditions are provided for general cyclic networks and a solution, when these conditions fail, is proposed. In addition, the results are exemplified by means of numerical simulations.

A local stability condition for dc grids with constant power loads
http://hdl.handle.net/2117/110130
A local stability condition for dc grids with constant power loads
Arocas Pérez, José; Griñó Cubero, Robert
Currently, there are an increasing number of power electronics converters in electrical grids, performing the most diverse tasks, but most of them, work as constant power loads (CPLs). This work presents a sufficient condition for the local stability of dc linear timeinvariant circuits with constant power loads for all the possible equilibria (depending on the drained power) of the systems. The condition is shown as a method with successive steps that should be met. Its main step is expressed as a linear matrix inequality test which is important for easiness of verification reasons. The method is illustrated with two examples: a singleport RLC circuit connected to a CPL and a twoport linear dc circuit connected to two CPLs.
20171108T09:02:59Z
Arocas Pérez, José
Griñó Cubero, Robert
Currently, there are an increasing number of power electronics converters in electrical grids, performing the most diverse tasks, but most of them, work as constant power loads (CPLs). This work presents a sufficient condition for the local stability of dc linear timeinvariant circuits with constant power loads for all the possible equilibria (depending on the drained power) of the systems. The condition is shown as a method with successive steps that should be met. Its main step is expressed as a linear matrix inequality test which is important for easiness of verification reasons. The method is illustrated with two examples: a singleport RLC circuit connected to a CPL and a twoport linear dc circuit connected to two CPLs.

Canonical realization of (2+1)dimensional BondiMetznerSachs symmetry
http://hdl.handle.net/2117/108683
Canonical realization of (2+1)dimensional BondiMetznerSachs symmetry
Batlle Arnau, Carles; Campello, Víctor; Gomis Torné, Joaquin
We construct canonical realizations of the (2+1)dimensional BondiMetznerSachs (bms3) algebra as symmetry algebras of a free KleinGordon (KG) field in 2+1 dimensions for both massive and massless cases. We consider two types of realizations, one on shell, written in terms of the Fourier modes of the scalar field, and the other off shell, with nonlocal transformations written in terms of the KG field and its momenta. These realizations contain both supertranslations and superrotations, for which we construct the corresponding Noether charges.
20171013T11:10:35Z
Batlle Arnau, Carles
Campello, Víctor
Gomis Torné, Joaquin
We construct canonical realizations of the (2+1)dimensional BondiMetznerSachs (bms3) algebra as symmetry algebras of a free KleinGordon (KG) field in 2+1 dimensions for both massive and massless cases. We consider two types of realizations, one on shell, written in terms of the Fourier modes of the scalar field, and the other off shell, with nonlocal transformations written in terms of the KG field and its momenta. These realizations contain both supertranslations and superrotations, for which we construct the corresponding Noether charges.