UPCommons - E-prints UPC Universitat Politècnica de Catalunya
E-prints UPC cobreix dues finalitats: per una banda, és el dipòsit institucional de la UPC que recull els articles de revista, les comunicacions de congrés i els reports de recerca generats en les activitats de recerca del personal docent i investigador de la universitat; per l'altra, és una eina que permet accelerar la producció científica, allotjant versions de documents prèvies a la publicació en una revista o a les actes d’un congrés.
Solid state transformer with low-voltage ride-through and current unbalance management capabilities - Alepuz Menéndez, Salvador; González, Francisco; Martín-Arnedo, Jacinto; Martínez Velasco, Juan Antonio
The solid state transformer is an emerging
technology which aims at replacing the conventional lowfrequency power transformer by means of a high-frequency transformer driven by a proper AC/AC power electronics
conversion system, at both transformer sides. In comparison with the conventional power transformer, the solid state transformer provides extended and enhanced operating capabilities that can be achieved with an appropriate controller design for the power electronics converters. In this work, the interaction of the solid state transformer with a distribution system is analyzed under different operating conditions. Bidirectional active power flow,
full reactive power control, low-voltage side current unbalance management and high-voltage side...
Magnet shape influence on the performance of AFPMM in a torus configuration - Saavedra Ordóñez, Harold; Riba Ruiz, Jordi-Roger; Hernández Guiteras, Joan; Romeral Martínez, José Luis
The axial flux permanent magnet machine (AFPMM)is being increasingly demanded for special applications, particularly for transportation systems and concretely for inwheel applications. In this paper the effect of the magnets shape on the AFPMM performance has been analyzed by means of 3DFEM simulations. To this end the air-gap magnetic flux density, the back electromotive force (back-EMF), the cogging torque and the total torque waveforms of the analyzed AFPMMs with different magnets geometries have been studied and compared.
The harmonic content of all these variables has been also analyzed. These analyses are carried out to find out the more suitable geometry for...
Fractional-slot permanent magnet synchronous generator for low voltage applications - Andrada Gascón, Pedro; Blanqué Molina, Balduino; Martínez Piera, Eusebio; Torrent Burgués, Marcel; Sánchez López, José Antonio; Perat Benavides, Josep Ignasi
This paper considers the implementation and
application of a small direct drive fractional-slot permanent magnet synchronous generator for low voltages applications in
distributed generation. Finite element analysis of the generator is performed and the results are compared with those obtained
Inter-turn fault detection in five-phase PMSMs. Effects of the fault severity - Saavedra Ordóñez, Harold; Riba Ruiz, Jordi-Roger; Romeral Martínez, José Luis
This paper deals with the effects of inter-turn short circuit faults in five-phase permanent magnet synchronous motors (PMSMs). For this purpose a finiteelements model (FEM) of a faulty machine with 1, 2 and 4 inter-turns in short circuit is analyzed. From the results of this
model the effects of these fault severities in the stator currents and zero-sequence voltage components (ZSVC) harmonics is
analyzed and the possibility of developing a fault diagnosis scheme based on the changes in their spectral content is exposed. Moreover, the effect of the fault severity on the total power losses in the machine is presented. Inter-turn faults...
Extended magnetization of superconducting pellets in highly inhomogeneous magnetic field - Maynou Gil, Roger; López López, José; Granados, Xavier; Torres Cámara, Ricardo; Bosch Tous, Ricardo
The magnetization of superconducting pellets is a worth point in the development of trapped flux superconducting motors. Experimental and simulated data have been reported extensively according to
the framework of one or several pulses of a homogeneous magnetizing field applied to a pellet or a set of pellets. In case of cylindrical rotors of low power motors with radial excitation, however, the use of the
copper coils to produce the starting magnetization of the pellets produces a highly inhomogeneous magnetic field which cannot be reduced to a 2D standard model. In this work we present an analysis of
the magnetization of the superconducting...
PSO-based LQR controller for multi modular converters - Rakhshani, Elyas; Mir Cantarellas, Antonio; Remón, D.; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
In this paper a new application of PSO technique
for optimizing the controller parameters of multi modular
converters is presented. PSO based LQR controller is designed
for averaged model of modular converter and to obtain better
control parameters though the minimizing a quadraticperformance
index. In this method in order to have more
accuracy and better design for controller parameters, PSO
algorithm is added to find the gain matrix of the controller.
Simulation results show that with using this method better
dynamic responses are accessible.
Grid connection design and control of LCL+Trap filter based two-level VSC for wave power plant applications - Mir Cantarellas, Antonio; Rakhshani, Elyas; Remón, D.; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
This paper presents a filter design methodology
and control design strategy for LCL+Trap filters deployed in
large scale wave power plants. This filter topology appears as an
alternative for the widely used LCL filters, since effective
harmonic mitigation can be achieved while reducing the overall
passive filter components size. As a result, the use of LCL+Trap
filters for two-level power converters arise as a suitable power
processing solution to match the requirements of large scale wave
energy applications, since such well-known power converter
technology is very robust, reliable and very cost effective. The
designed LCL+Trap filter is validated through simulation by
performing a comparative analysis between LCL and LCL+Trap
filters, and finally,...
Modeling and validation of a flywheel energy storage lab-setup - Diaz Gonzalez, Francisco; Sumper, Andreas; Gomis Bellmunt, Oriol; Villafafila Robles, Roberto
This work deals with the modeling, control and experimental validation of a flywheel test bench which is part of IREC’s lab-scale microgrid. The storage device has been
designed as a proof of concept. It is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous
Machine. The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These
power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also
regulate the reactive power at the point of common coupling with the external grid. Vector...
Passive and Active Methods of Islanding for PV systems - Skocil, Tomas; Gomis Bellmunt, Oriol; Montesinos Miracle, Daniel; Galcerán Arellano, Samuel; Rull Duran, Joan
This paper presents a review of some techniques for islanding detection, especially by using inverter based DG applications and it also focuses on several islanding detection methods for a single- phase current-control voltage inverter working with a PV system connected into the grid. It is deliberated a single-phase inverter with maximum power of 5 kW. Islanding detection methods are investigated, simulated and evaluated in MATLAB / SIMULINK.
Requirements for EV charge stations with photovoltaic generation and storage - Cairó, Ignasi; Sumper, Andreas
With the increase in electric mobility, public and private charge facilities will be required to provide solutions adjusted to the actual needs and requirements. A new
methodology for dimensioning charge stations for electric vehicles (EVs) is presented in this paper. Such proposal is based on the Markov chains, and uses as output rates, the capabilities of the charge station in providing energy from the sun through
photovoltaic generation, stored energy in local batteries and also as a back-up the power grid. A numerical result is also presented for a better understanding of the process.
Reduction of the students´ evaluation of education quality questionnaire - Corbalán Fuertes, Montserrat; Plaza García, Inmaculada; Hervas, Eva; Aldabas Rubira, Emiliano; Arcega, Francisco
Assessment of students and the evaluation of their
satisfaction has been an important element in the improvement
of teaching quality in all the Higher Education areas.
Specifically the student participation in Computer Science (C
and Information System (IS) has been highlight valued. Thus a
large number of methodologies and standard tools regarding
student evaluation has been developed. Specifically, the
Students ́ Evaluation of Education Quality (SEEQ) is a tool
that is validated for international use. But its use leads to
several problems, such as the low voluntary participation of
students. To solve these problems, a short version of this
questionnaire developed using statistic tools is proposed. After
using the proposed new version,...
Power control of VSC HVDC converters for limiting the influence of ac unbalanced faults on multi-terminal DC grids - Suul, Jon Are; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
It will be important for the operation of future multi-terminal HVDC systems that each converter unit is capable of limiting the influence of nearby AC faults on the DC grid. Thus, the local control systems at each terminal should be able to prevent double frequency active power oscillations caused by unbalanced AC faults from propagating to the DC-side of the converter. A simple approach for achieving this objective, while ensuring that the converter currents are limited to safe values, is therefore presented in this paper. The proposed method is based on estimation of Positive and Negative Sequence Virtual Flux components...
Multichannel high-power high-frequency converters for induction heating - Martín Segura, Guillermo; Sala Pérez, Pau; Montesinos Miracle, Daniel; Ferrater Simón, Coia; López Mestre, Joaquim
This paper studies a converter structure based on the connection of basic topologies to form
a multichannel converter for induction heating applications. The aim of using basic topologies
is to provide a reduction of design time, the cost derived from higher volume production, stock
components and installation and maintenance work. First, the aim of the paper is introduced,
afterwards the topology is discussed and then implemented
Grid-connected to/from off-grid transference for micro-grid inverters - Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel; Montesinos Miracle, Daniel
This paper compares two methods for controlling the on-line transference from connected to stand-alone
mode and vice versa in converters for micro-grids. The first proposes a method where the converter
changes from CSI (Current Source Inverter) in grid-connected mode to VSI (Voltage Source Inverter) in
off-grid. In the second method, the inverter always works as a non-ideal voltage source, acting as VSI,
using AC droop control strategy.