Articles de revista
http://hdl.handle.net/2117/4008
2015-11-28T17:06:44ZDecentralized control of a nine-phase permanent magnet generator for offshore wind turbines
http://hdl.handle.net/2117/79469
Decentralized control of a nine-phase permanent magnet generator for offshore wind turbines
Prieto Araujo, Eduardo; Junyent Ferré, Adrià; Lavemia Ferrer, David; Gomis Bellmunt, Oriol
This paper presents a decentralized current control approach for a nine-phase wind turbine generator. This type of generator has three different three-phase stators sharing the same machine yoke and connected to the grid by means of three different voltage source back-to-back power converters. Due to the machine configuration, magnetic couplings are present between the three stators, complicating the design and implementation of the machine current controllers. Rather than a centralized control approach, this paper proposes a methodology to design a decentralized machine control to regulate the active and reactive power flowing through each stator independently. A complete dynamic analysis is performed in order to design the controller to reduce the coupling effects within the machine, while ensuring a proper dynamic performance. The control strategy is validated through simulation and experimental results.
2015-11-19T10:22:03ZPrieto Araujo, EduardoJunyent Ferré, AdriàLavemia Ferrer, DavidGomis Bellmunt, OriolThis paper presents a decentralized current control approach for a nine-phase wind turbine generator. This type of generator has three different three-phase stators sharing the same machine yoke and connected to the grid by means of three different voltage source back-to-back power converters. Due to the machine configuration, magnetic couplings are present between the three stators, complicating the design and implementation of the machine current controllers. Rather than a centralized control approach, this paper proposes a methodology to design a decentralized machine control to regulate the active and reactive power flowing through each stator independently. A complete dynamic analysis is performed in order to design the controller to reduce the coupling effects within the machine, while ensuring a proper dynamic performance. The control strategy is validated through simulation and experimental results.Renewable energy emulation concepts for microgrids
http://hdl.handle.net/2117/79462
Renewable energy emulation concepts for microgrids
Prieto Araujo, Eduardo; Olivella Rosell, Pol; Cheah Mañé, Marc; Villafafila Robles, Roberto; Gomis Bellmunt, Oriol
This paper reviews the renewable energy systems emulators proposals for microgrid laboratory testing platforms. Four emulation conceptual levels are identified based on the literature analysis performed. Each of these levels is explained through a microgrid example, detailing its features and possibilities. Finally, an experimental microgrid, built based on emulators, is presented to exemplify the system performance. (C) 2015 Elsevier Ltd. All rights reserved.
2015-11-19T09:04:16ZPrieto Araujo, EduardoOlivella Rosell, PolCheah Mañé, MarcVillafafila Robles, RobertoGomis Bellmunt, OriolThis paper reviews the renewable energy systems emulators proposals for microgrid laboratory testing platforms. Four emulation conceptual levels are identified based on the literature analysis performed. Each of these levels is explained through a microgrid example, detailing its features and possibilities. Finally, an experimental microgrid, built based on emulators, is presented to exemplify the system performance. (C) 2015 Elsevier Ltd. All rights reserved.La conmutación del inversor trifásico, estrategia y comprensión
http://hdl.handle.net/2117/79413
La conmutación del inversor trifásico, estrategia y comprensión
Llonch Masachs, Marc; Montesinos Miracle, Daniel
Los inversores trifásicos llevan ya décadas presentes en la industria. La necesidad de sintetizar tensiones trifásicas sinusoidales desde un bus de continua, está presente tanto en la alimentación de cargas como en la inyección de energía a la
red. Convertidores DC/AC, variadores de velocidad, etc… son equipos habituales altamente utilizados pero, ¿sabemos cómo dan forma a la tensión para obtener un sistema trifásico? De entre las múltiples estrategias existentes vamos a tratar de
entender mejor las características y diferencias entre la conmutación por SPWM (Sinusoidal Pulse Width Modulation) versus la conmutación por SVPWM (Space Vector Pulse Width Modulation).
2015-11-18T13:19:00ZLlonch Masachs, MarcMontesinos Miracle, DanielLos inversores trifásicos llevan ya décadas presentes en la industria. La necesidad de sintetizar tensiones trifásicas sinusoidales desde un bus de continua, está presente tanto en la alimentación de cargas como en la inyección de energía a la
red. Convertidores DC/AC, variadores de velocidad, etc… son equipos habituales altamente utilizados pero, ¿sabemos cómo dan forma a la tensión para obtener un sistema trifásico? De entre las múltiples estrategias existentes vamos a tratar de
entender mejor las características y diferencias entre la conmutación por SPWM (Sinusoidal Pulse Width Modulation) versus la conmutación por SVPWM (Space Vector Pulse Width Modulation).Using the instantaneous power of a free acceleration test for squirrel-cage motor parameters estimation
http://hdl.handle.net/2117/79352
Using the instantaneous power of a free acceleration test for squirrel-cage motor parameters estimation
Kojooyan, Hengameh; Monjo Mur, Lluís; Córcoles López, Felipe; Pedra Durán, Joaquim
A new parameters determination method for squirrel-cage induction motors is presented. As a main contribution, the method uses the instantaneous electrical power and the mechanical speed measured in a free acceleration test to estimate the double-cage model parameters. The parameters are estimated from the machine impedance calculated at several points. At speed points where the double-cage effect is significant, i.e., between the zero speed point and the maximum torque point, the machine impedance is evaluated by the instantaneous power method, and at speed points where the double-cage effect is not significant, i.e., between the maximum torque point and synchronism, the machine impedance is evaluated by a dynamic-model-based linear least-square method. The proposed method has been applied to obtain the parameters of three motors tested in the laboratory. To check the method accuracy, the steady-state torque and current-slip curves predicted by the estimated parameters are successfully compared with those measured in the laboratory.
2015-11-17T11:16:19ZKojooyan, HengamehMonjo Mur, LluísCórcoles López, FelipePedra Durán, JoaquimA new parameters determination method for squirrel-cage induction motors is presented. As a main contribution, the method uses the instantaneous electrical power and the mechanical speed measured in a free acceleration test to estimate the double-cage model parameters. The parameters are estimated from the machine impedance calculated at several points. At speed points where the double-cage effect is significant, i.e., between the zero speed point and the maximum torque point, the machine impedance is evaluated by the instantaneous power method, and at speed points where the double-cage effect is not significant, i.e., between the maximum torque point and synchronism, the machine impedance is evaluated by a dynamic-model-based linear least-square method. The proposed method has been applied to obtain the parameters of three motors tested in the laboratory. To check the method accuracy, the steady-state torque and current-slip curves predicted by the estimated parameters are successfully compared with those measured in the laboratory.Study of resonances in 1 x 25 kV AC traction systems
http://hdl.handle.net/2117/79350
Study of resonances in 1 x 25 kV AC traction systems
Monjo Mur, Lluís; Sainz Sapera, Luis
AC traction systems are 1 x 25 or 2 x 25 kV 50-Hz single-phase, non-linear, time-varying loads that can cause power quality problems. One of the main concerns about these systems is voltage distortion, because adjustable-speed drives for trains may inject harmonic currents of frequencies below 2kHz. Since the presence of parallel resonances in the contact feeder section of the traction circuit worsens the scenario, traction system resonance phenomena should be analyzed to prevent problems. Several works addressed these phenomena, but they only drew weak numerical conclusions based on the frequency scan method. This article studies 1 x 25 kV traction system resonances at pantograph terminals and provides more effective analytical expressions to locate them and determine the impact of traction system parameters on them. These expressions are validated from several traction systems in the literature.
2015-11-17T10:34:12ZMonjo Mur, LluísSainz Sapera, LuisAC traction systems are 1 x 25 or 2 x 25 kV 50-Hz single-phase, non-linear, time-varying loads that can cause power quality problems. One of the main concerns about these systems is voltage distortion, because adjustable-speed drives for trains may inject harmonic currents of frequencies below 2kHz. Since the presence of parallel resonances in the contact feeder section of the traction circuit worsens the scenario, traction system resonance phenomena should be analyzed to prevent problems. Several works addressed these phenomena, but they only drew weak numerical conclusions based on the frequency scan method. This article studies 1 x 25 kV traction system resonances at pantograph terminals and provides more effective analytical expressions to locate them and determine the impact of traction system parameters on them. These expressions are validated from several traction systems in the literature.Study of resonance in wind parks
http://hdl.handle.net/2117/79320
Study of resonance in wind parks
Monjo Mur, Lluís; Sainz Sapera, Luis; Liang, Jun; Pedra Durán, Joaquim
Wind turbine harmonic current emissions are a well-known power quality problem. These emissions flow through wind park impedances, leading to grid voltage distortion. Parallel resonance may worsen the problem because it increases voltage distortion around the resonance frequency. Hence, it is interesting to analyze the parallel resonance phenomenon. The paper explores this phenomenon in wind parks and provides analytical expressions to determine parallel resonances. (C) 2015 The Authors. Published by Elsevier B.V.
2015-11-16T15:09:28ZMonjo Mur, LluísSainz Sapera, LuisLiang, JunPedra Durán, JoaquimWind turbine harmonic current emissions are a well-known power quality problem. These emissions flow through wind park impedances, leading to grid voltage distortion. Parallel resonance may worsen the problem because it increases voltage distortion around the resonance frequency. Hence, it is interesting to analyze the parallel resonance phenomenon. The paper explores this phenomenon in wind parks and provides analytical expressions to determine parallel resonances. (C) 2015 The Authors. Published by Elsevier B.V.Parameter estimation of squirrel-cage motors with parasitic torques in the torque–slip curve
http://hdl.handle.net/2117/79316
Parameter estimation of squirrel-cage motors with parasitic torques in the torque–slip curve
Monjo Mur, Lluís; Córcoles López, Felipe; Pedra Durán, Joaquim
This paper studies parasitic torques in steady-state torque–slip curves of squirrel-cage induction motors. The
curves of nine motors (small, medium and large size units), three of which were measured in the range s = 2 to 0, are
analysed. The torque–slip curves of eight of these nine motors differ significantly from the smooth curves predicted by the
classical single- and double-cage models: a torque dip at large slips in the motoring regime and a notable torque increase
in the braking regime occur. As parasitic torques have been traditionally associated with space harmonics, two singlecage
chain models (which consider the space harmonics) are tested to fit the measured torque and current of the three
measured motors: one neglects the skin effect, leading to the wrong torque prediction, whereas the other (the chain
model proposed in the early 60s in the literature) considers the skin effect, leading to an accurate torque prediction.
2015-11-16T14:04:52ZMonjo Mur, LluísCórcoles López, FelipePedra Durán, JoaquimThis paper studies parasitic torques in steady-state torque–slip curves of squirrel-cage induction motors. The
curves of nine motors (small, medium and large size units), three of which were measured in the range s = 2 to 0, are
analysed. The torque–slip curves of eight of these nine motors differ significantly from the smooth curves predicted by the
classical single- and double-cage models: a torque dip at large slips in the motoring regime and a notable torque increase
in the braking regime occur. As parasitic torques have been traditionally associated with space harmonics, two singlecage
chain models (which consider the space harmonics) are tested to fit the measured torque and current of the three
measured motors: one neglects the skin effect, leading to the wrong torque prediction, whereas the other (the chain
model proposed in the early 60s in the literature) considers the skin effect, leading to an accurate torque prediction.Testing of three-phase equipment under voltage sags
http://hdl.handle.net/2117/79313
Testing of three-phase equipment under voltage sags
Rolán Blanco, Alejandro; Córcoles López, Felipe; Pedra Durán, Joaquim; Monjo Mur, Lluís; Bogarra Rodríguez, Santiago
This paper provides insight into the testing of three-phase equipment exposed to voltage sags caused by faults.
The voltage sag recovers at the fault-current zeros, leading to a ‘discrete’ voltage recovery, that is, the fault is cleared in
different steps. In the literature, the most widespread classification divides ‘discrete’ sags into 14 types. The authors study shows that it is generally sufficient to consider only five sag types for three-phase equipment, here called ‘time-invariant
(TI)’ equipment. As the remaining nine sag types cause identical equipment behaviour in Park or Ku variables, the number of laboratory tests (or of extensive simulations) on equipment under sags is reduced by a ratio of 14/5. The study is validated by simulation of a three-phase induction generator and a three-phase inverter, which are ‘TI’, and a threephase
diode bridge rectifier, which is not ‘TI’. Both analytical study and simulation results are validated by testing a three-phase induction motor and a three-phase diode bridge rectifier.
2015-11-16T13:24:24ZRolán Blanco, AlejandroCórcoles López, FelipePedra Durán, JoaquimMonjo Mur, LluísBogarra Rodríguez, SantiagoThis paper provides insight into the testing of three-phase equipment exposed to voltage sags caused by faults.
The voltage sag recovers at the fault-current zeros, leading to a ‘discrete’ voltage recovery, that is, the fault is cleared in
different steps. In the literature, the most widespread classification divides ‘discrete’ sags into 14 types. The authors study shows that it is generally sufficient to consider only five sag types for three-phase equipment, here called ‘time-invariant
(TI)’ equipment. As the remaining nine sag types cause identical equipment behaviour in Park or Ku variables, the number of laboratory tests (or of extensive simulations) on equipment under sags is reduced by a ratio of 14/5. The study is validated by simulation of a three-phase induction generator and a three-phase inverter, which are ‘TI’, and a threephase
diode bridge rectifier, which is not ‘TI’. Both analytical study and simulation results are validated by testing a three-phase induction motor and a three-phase diode bridge rectifier.Model of aeronautical ground lighting system transformers
http://hdl.handle.net/2117/79229
Model of aeronautical ground lighting system transformers
lomvarte, daniel; Monjo Mur, Lluís; Sainz Sapera, Luis; Pedra Durán, Joaquim
Airport ground lighting (AGL) systems provide visual reference to aircrafts during
airport operations. In AGL systems, constant current regulators feed a beacon circuit supplied
through isolation transformers. Component modeling is necessary to simulate AGL systems, and
thus characterize and predict their behavior. This paper presents an isolation transformer model
including transformer core saturation. Moreover, a procedure to estimate transformer model
parameters is proposed. Both the model and the estimation method are validated with extensive
measurements on more than 20 isolation transformers of different power ratings and trade names.
2015-11-13T12:15:36Zlomvarte, danielMonjo Mur, LluísSainz Sapera, LuisPedra Durán, JoaquimAirport ground lighting (AGL) systems provide visual reference to aircrafts during
airport operations. In AGL systems, constant current regulators feed a beacon circuit supplied
through isolation transformers. Component modeling is necessary to simulate AGL systems, and
thus characterize and predict their behavior. This paper presents an isolation transformer model
including transformer core saturation. Moreover, a procedure to estimate transformer model
parameters is proposed. Both the model and the estimation method are validated with extensive
measurements on more than 20 isolation transformers of different power ratings and trade names.Semiconductores de banda de prohibición ancha
http://hdl.handle.net/2117/79102
Semiconductores de banda de prohibición ancha
Lledó Ponsati, Tomàs; Montesinos Miracle, Daniel
En los últimos años han aparecido nuevos materiales semiconductores que mejoran las
propiedades de los empleados hasta la actualidad. Este artículo reflexiona sobre las ventajas e
inconvenientes que estos nuevos materiales pueden aportar al campo de la electrónica de
potencia y cuáles serán las consecuencias para los usuarios.
2015-11-12T10:36:20ZLledó Ponsati, TomàsMontesinos Miracle, DanielEn los últimos años han aparecido nuevos materiales semiconductores que mejoran las
propiedades de los empleados hasta la actualidad. Este artículo reflexiona sobre las ventajas e
inconvenientes que estos nuevos materiales pueden aportar al campo de la electrónica de
potencia y cuáles serán las consecuencias para los usuarios.