Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 348 results
  • Thermal and efficiency analysis of five-level multilevel-clamped multilevel converter considering grid codes

     Ke, Ma; Muñoz Aguilar, Raul Santiago; Rodriguez Cortes, Pedro; Blaabjerg, Frede
    IEEE transactions on industry applications
    Vol. 50, num. 1, p. 415-423
    DOI: 10.1109/TIA.2013.2266391
    Date of publication: 2014-02
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In this paper, a five-level multilevel-clamped multilevel converter (5L-MLC2) topology is analyzed based on a typical grid integration application for renewable energy system. The loss and thermal distributions of the power devices in different switching legs are investigated and illustrated under rated condition. Afterward, a loss and efficiency evaluation method is proposed and applied which takes into account various injected reactive power ranges regulated by the grid codes. It is concluded that the loss and thermal distributions of the 5L-MLC2 multilevel topology are unequal between the clamping switching legs and the main switching legs; it also shows a good and consistent efficiency characteristic under different output power ranges when complying with the grid codes.

  • A sensor-less sliding mode control scheme for a stand-alone wound rotor synchronous generator under unbalanced load conditions

     Muñoz Aguilar, Raul Santiago; Rodriguez Cortes, Pedro; Doria Cerezo, Arnau; Candela Garcia, Jose Ignacio; Luna Alloza, Alvaro
    International journal of electrical power and energy systems
    Vol. 60, p. 275-282
    DOI: 10.1016/j.ijepes.2014.03.003
    Date of publication: 2014-04-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper presents a sliding mode control for a wound rotor synchronous machine acting as an isolated generator connected to an unbalanced load. In order to simplify the control methodology, the standard dq-model of the machine is connected to a balanced resistive load. A switching function is defined in order to fulfill the control objective. From the desired surface, the standard sliding methodology is applied to obtain a robust and very simple controller. Then, the actual measured voltage of the machines is acquired and treated trough a frequency locked loop algorithm in order to extract the positive sequence and control it to guarantee a good definition of the park transformation. A phase locked loop algorithm is also used to avoid speed sensors. Numerical simulations and experimental results validate the control law and show good performance and a fast response to load and reference changes

  • Harmonic compensation analysis in offshore wind power plants using hybrid filters

     Hasan, Khurshid N Md; Kalle, Rauma; Luna Alloza, Alvaro; Candela Garcia, Jose Ignacio; Rodriguez Cortes, Pedro
    IEEE transactions on industry applications
    Vol. 50, num. 3, p. 2050-2060
    DOI: 10.1109/TIA.2013.2286216
    Date of publication: 2014-05-16
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The harmful effects of harmonics are an important issue in wind power plants (WPPs), especially in offshore applications. In offshore WPPs, the wind turbines are linked to the network through high-power converters that produce harmonics at relative low frequencies. Moreover, in the network of a WPP, the propagation of noncharacteristic harmonics and the effect of resonance contribute as well in boosting the harmonic distortion. In this paper, a solution for compensating the harmonics in a WPP by means of using hybrid filters is proposed. In this paper, not only the filtering solution is tested, but also a method for finding the best place where to connect the filter, based on a modal analysis or a harmonic modal resonance analysis, is implemented. The proposed solution has been tested by considering the model of a real 400-MW offshore WPP as the study case. As it will be shown, the hybrid filter is capable of damping the resonances in the plant, while the analysis conducted permits us to optimize its location in the plant

  • Daily solar energy estimation for minimizing energy storage requirements in PV power plants

     Beltrán San Segundo, Héctor; Pérez Soler, Emilio; Aparicio Marín, Néstor; Rodriguez Cortes, Pedro
    IEEE Transactions on Sustainable Energy
    Vol. 4, num. 2, p. 474-481
    DOI: 10.1109/TSTE.2012.2206413
    Date of publication: 2013-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper proposes an optimized energy management strategy (EMS) for photovoltaic (PV) power plants with energy storage (ES) based on the estimation of the daily solar energy production. This EMS produces a constant-by-hours power reference which mitigates the stochastic nature of PV production typically associated to the solar resource, and enables PV power plants to take part in the day and intraday electricity markets. The possibility of using the intraday market sessions to refine the plant's power reference paves the way to minimizing the energy capacity ratings of the ES system required to operate the PV power plant without incurring excessive production deviations. This proposal is analyzed on an annual basis using actual irradiance data and theoretical irradiance models extracted from official databases.

  • Access to the full text
    Thermal and efficiency analysis of five-level multi-level clamped multilevel converter considering grid codes  Open access

     Ma, Ke; Muñoz Aguilar, Raul Santiago; Rodriguez Cortes, Pedro; Blaabjerg, Frede
    IEEE transactions on industry applications
    DOI: 10.1109/TIA.2013.2266391
    Date of publication: 2013-06-05
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In this paper a five-level Multi-Clamped Multilevel Converter (5L-MLC2) topology is analyzed based on a typical grid integration application for renewable energy system. The loss and thermal distribution of the power devices in different switching legs are investigated and illustrated under rated condition. Afterwards, a loss and efficiency evaluation method is proposed and applied which take into account various injected reactive power ranges regulated by the grid codes. It is concluded that the loss and thermal distribution of 5L-MLC2 multilevel topology is unequal between the clamping switching legs and the main switching legs, it also shows a good and consistent efficiency characteristic under different output power ranges when complying with the grid codes.

  • Predictive power control for PV plants with energy storage

     Pérez Soler, Emilio; Aparicio Marín, Néstor; Beltrán San Segundo, Héctor; Rodriguez Cortes, Pedro
    IEEE Transactions on Sustainable Energy
    Vol. 4, num. 2, p. 482-490
    DOI: 10.1109/TSTE.2012.2210255
    Date of publication: 2013-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This work presents a model predictive control (MPC) approach to manage in real-time the energy generated by a grid-tied photovoltaic (PV) power plant with energy storage (ES), optimizing its economic revenue. This MPC approach stands out because, when a long enough prediction horizon is used, the saturation of the ES system (ESS) can be advanced by means of a prediction model of the PV panels production. Therefore, the PV+ES power plant can modify its production so as to manage the power deviations with regard to that committed in the daily and intraday electricity markets, with the objective of reducing economic penalties. The initial power commitment is supposed in this work to be given by a higher level energy management operator. By a proper definition of its objective function, the predictive control allows us to economically optimize the PV+ES power plant performance. This control strategy is tested in simulations with actual data measured for different days with varying meteorological conditions. Results provide a good reference on the economic benefits which can be obtained thanks to the MPC introduction.

  • Common-mode Voltage Cancellation in Single- and Three-Phase Transformer-less PV Power Converters  Open access

     Vázquez Guzman, Gerardo
    Department of Electrical Engineering, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    La generación de energía eléctrica es una causa de preocupación continua alrededor del mundo. Se han hecho una gran cantidad de esfuerzos en este sentido para intentar cubrir la creciente demanda de energía eléctrica. Pero no solo la demanda de energía eléctrica esta creciendo sino también se requiere que esta sea limpia. En este sentido, muchos países están aprovechando el uso de sistemas de generación de energía eléctrica de fuentes renovables como la energía del viento y la energía solar.Los sistemas que generan energía eléctrica a partir de energía solar actualmente proporcionan un alto porcentaje del total de energía producida. De acuerdo con el ultimo reporte de la agencia de energía internacional (IEA por sus siglas en inglés)en referencia al programa de sistemas de potencia fotovoltaica (PVPS por sus siglas en inglés), el total de potencia fotovoltaica instalada a finales de 2009 fue de alrededor de 20.3 GW de los cuales 6.188 GW fueron instalados en 2009. Del total de potencia fotovoltaica instalada en 2009, 6.113 GW corresponde a sistemas conectados a la red eléctrica. El crecimiento de este tipo de sistemas se debe a la introducción de nuevas tecnologías y desarrollos que han permitido reducir los costos de diseño, manufactura e instalación de una instalación solar.Dado que el mayor porcentaje del total de la energía fotovoltaica instalada proviene de sistemas conectados a la red eléctrica, este trabajo de tesis esta enfocado al análisis y a la presentación de soluciones en sistemas fotovoltaicos conectados a la red eléctrica sin transformador los cuales pueden proporcionar eficiencias mas altas que aquellos que usan transformador. En este sentido, cuando no existe transformador entre el convertidor de potencia y la red eléctrica, corrientes parásitas pueden circular a través de los condensadores parásitos y causar serios problemas para el sistema y sus usuarios.La principal tarea de este trabajo de tesis ha sido analizar y evaluar la operación de diferentes topologías sin transformador que han sido encontradas en la bibliografía y de esta forma proponer algunas soluciones para minimizar o eliminar las corrientes parásitas que pueden presentarse debido a las características del panel fotovoltaico y de las condiciones de operación generales del sistema.

    Electrical Energy generation is an issue that is continuously cause of concern around the world. Many efforts have been done in this sense to cover the requirements of the constantly growing in the electrical energy demand. But not only the electrical energy demand is growing but also clean electrical energy demand. In this sense, many countries are taking advantage from the renewable energy generation systems, considering mainly wind and solar energy. Solar energy systems provide a high percentage of the total energy production, according with the latest report of the International Energy Agency (IEA) regarding Photovoltaic Power System Program (PVPS), the cumulative installed PV power at the end of 2009 it was around 20.3 GW out of which 6.188 GW were installed in 2009. From the total PV power installed in 2009, 6.113 are grid connected systems. The growing of the PV systems is due to the new technologies and developments that have permitted to reduce costs in the total design and installation of a PV source. As the major percentage of the total PV energy installed is from grid connected systems, this thesis work deals with the analysis and proposals in the transformerless grid-connected PV systems which can provide higher efficiencies regarding PV system with transformer. In this sense, when there is not transformer between the electrical grid and the power converter, a problem regarding leakage ground currents appears, this is the main issue in this thesis work. The main research task in this thesis work is to analyze and evaluate the operation of the different transformerless topologies presented in the bibliography and then to provide some solutions to minimize the leakage ground current phenomenon in order to comply with the standard requirements.

  • IEEE Power Electronics Society Paper Award

     Rodriguez Cortes, Pedro; Luna Alloza, Alvaro; Muñoz Aguilar, Raul Santiago; Etxeberria Otadui, Ion; Teodorescu, Remus; Blaabjerg, Frede
    Award or recognition

     Share

  • IEEE Power Electronics Society Prize Letter Award

     Rodriguez Cortes, Pedro; Dias Bellar, Maria; Muñoz Aguilar, Raul Santiago; Busquets Monge, Sergio
    Award or recognition

     Share

  • Pla d'Actuació SEER

     Rodriguez Cortes, Pedro
    Competitive project

     Share

  • Grid harmonic detection and system resonances indentification in wave power plant applications

     Nisak, Khairul; Mir Cantarellas, Antonio; Luna Alloza, Alvaro; Candela Garcia, Jose Ignacio; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 1644-1649
    DOI: 10.1109/IECON.2013.6699379
    Presentation's date: 2013-11-13
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    There is a growing interest in electrical grid connection of single unit Wave Energy Converters (WECs), as well as the multiple units based Wave Power Plant (WPP) applications. Due to the increasing integration of high power converters in WPP, additional concerns on the harmonic current mitigation of WEC device arise which requires the grid filter installation. Furthermore, the identification and appropriate mitigation of additional harmonics at the WPP level is needed, as any inductances and capacitors of the WPP can interact with the resonant frequency of the entire system and lead to detrimental effects on equipment. The present paper focuses on the potential harmonic studies of a realistic proposed WPP layout, in which the system resonances are identified by performing the frequency scan and modal analysis (HRMA) methods. The later technique has the ability of determining the participation factor of each bus, finding in this way the nodes in the system that have more influence on the obtained results. In this way, the most suitable nodes in which additional filtering solutions should be implemented can be identified.

  • Decentralized control of MTDC networks with energy storage and distributed generation

     Gavriluta, Catalin; Candela Garcia, Jose Ignacio; Citro, Costantino; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    IEEE Annual International Energy Conversion Congress and Exhibition for the Asia/Pacific
    p. 2657-2663
    DOI: 10.1109/ECCE.2013.6647044
    Presentation's date: 2013-09-15
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Multi-terminal dc (MTDC) networks are drawing a lot of interest lately in applications related to distributed generation, especially in those that integrate energy storage. Several approaches for controlling the operation of such systems have been proposed in the literature; however the existing structures can be significantly enhanced. This paper proposes an improved primary control layer, based on droop and dc-bus signaling to serve as a base framework for implementing a hierarchical control structure in a MTDC system. As it will be further discussed in this work, five operating bands as well as various droop characteristics for different elements connected to the dc-bus were defined. For the energy storage the state of charge (SoC) was taken into account at the primary control level and it was included in the droop characteristic, creating a two variables droop surface. The proposed control strategy was validated through simulation and experimental results obtained from a case study that involves a micro dc network composed of a PV generator, a lead-acid battery and one connection point to the ac grid. © 2013 IEEE.

    Multi-terminal dc (MTDC) networks are drawing a lot of interest lately in applications related to distributed generation, especially in those that integrate energy storage. Several approaches for controlling the operation of such systems have been proposed in the literature; however the existing structures can be significantly enhanced. This paper proposes an improved primary control layer, based on droop and dc-bus signaling to serve as a base framework for implementing a hierarchical control structure in a MTDC system. As it will be further discussed in this work, five operating bands as well as various droop characteristics for different elements connected to the dc-bus were defined. For the energy storage the state of charge (SoC) was taken into account at the primary control level and it was included in the droop characteristic, creating a two variables droop surface. The proposed control strategy was validated through simulation and experimental results obtained from a case study that involves a micro dc network composed of a PV generator, a lead-acid battery and one connection point to the ac grid. © 2013 IEEE.

  • Analysis on capability of harmonic damping using active filter acting as resistive harmonic impedance

     Hasan, Khurshid N Md; Luna Alloza, Alvaro; Candela Garcia, Jose Ignacio; Rodriguez Cortes, Pedro
    IEEE Annual International Energy Conversion Congress and Exhibition for the Asia/Pacific
    p. 2928-2933
    DOI: 10.1109/ECCE.2013.6647082
    Presentation's date: 2013-09
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper presents the analysis of shunt active filter (SAF) in harmonic damping. SAF with voltage-based detection control act as an active damping and able to attenuate harmonic propagation throughout the power distribution network. The active filter is implemented on two different power line networks to assess its practicality in different network configuration. The first network is 220-V distribution power line and the second network is the reduced equivalent WPP network of 150-kV, 444.4-MVA. Assessment on the best place for active filter implementation is supported by using harmonic resonance mode analysis method.

    This paper presents the analysis of shunt active filter (SAF) in harmonic damping. SAF with voltage-based detection control act as an active damping and able to attenuate harmonic propagation throughout the power distribution network. The active filter is implemented on two different power line networks to assess its practicality in different network configuration. The first network is 220-V distribution power line and the second network is the reduced equivalent WPP network of 150-kV, 444.4-MVA. Assessment on the best place for active filter implementation is supported by using harmonic resonance mode analysis method.

  • Analysis and comparison of battery energy storage technologies for grid applications

     Saez-de Ibarra, Andoni; Milo, Aitor; Gaztañaga, Haizea; Etxeberria Otadui, Ion; Rodriguez Cortes, Pedro; Bacha, Seddik; Debusschere, V.
    IEEE PowerTech Conference
    DOI: 10.1109/PTC.2013.6652509
    Presentation's date: 2013-06-20
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Battery Energy Storage Systems (BESSs) could contribute to the generation/consumption balance of the grid and could provide advanced functionalities at different grid levels (generation, T&D, end-user and RES integration). In this paper an analysis and comparison of Battery Energy Storage (BES) technologies for grid applications is carried out. The comparison is focused on the most installed technologies in the recent experimental BESS installations. Furthermore, the paper presents a new methodology aimed at selecting the most suitable BES technology for a specific grid application. This methodology defines a priority level for each technical and economical characteristic of the BES technologies. Finally, the proposed methodology is applied for a specific grid application confirming its contribution in the selection of the best-suited technology.

  • Analysis of ferroresonance effects in distribution networks with distributed source units

     Monadi, Mehdi; Luna Alloza, Alvaro; Candela Garcia, Jose Ignacio; Rocabert Delgado, Joan; Fayezizadeh, Mostafa; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 1974-1979
    DOI: 10.1109/IECON.2013.6699434
    Presentation's date: 2013-11-13
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The connection of Distributed Generation (DG) units to existing networks may give rise to harmful effects on the network and the DG units itself. Therefore, due to increasing penetration of DG units, it is important to consider these effects in order to avoid some of harmful events. Ferroresonance is one of these destructive phenomena. Over voltages due to this phenomena can damage devices which are connected to the network. In DG systems, due to the use of capacitor banks which are used for VAR compensation, grid connection filters, etc. ferroresonance may appear. Also, special operations like islanding, may lead these systems to ferroresonance. In traditional systems ferroresonance normally appear after there is an unbalance in the system. Nevertheless, for networks with significant penetration of DG units, the situation that gives rise to ferroresonance may be different from traditional systems and they can happen without any unbalancing occurrence. In this paper a distribution system integrating wind (WT) and photovoltaic (PV) power systems has been evaluated in order to analyze the performance of ferroresonance in such systems. Finally, the most appropriate techniques to prevent its appearance, and the associated over voltages, have been studied and implemented using PSCAD/EMTDC.

  • Modeling and control of multi modular converters using optimal LQR controller with integral action

     Rakhshani, Elyas; Mir Cantarellas, Antonio; Remón, D.; Rodriguez Cortes, Pedro; Candela Garcia, Jose Ignacio
    IEEE Energy Conversion Congress and Exposition
    p. 3965-3970
    DOI: 10.1109/ECCE.2013.6647226
    Presentation's date: 2013-09
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    A new application of LQR controller with the ability of reference tracking for a multi modular converter with several cells is proposed. First, the mathematical model for the grid connected MMC is presented and then, the small signal state space model is obtained. MMC is a very complex MIMO system with several state variables and global control for this system is very important issue. Optimal advanced controller based on linear quadratic regulator with integral action is a very good candidate for controlling the AC signals and energy balancing in multi cells MMC system. The performance and validity of obtained model and designed linear controller are evaluated with non-linear model of MMC in SimPower System toolbox/Matlab. Simulation results are verified the excellent performance of the proposed approach in the transient and steady state operational conditions.

    A new application of LQR controller with the ability of reference tracking for a multi modular converter with several cells is proposed. First, the mathematical model for the grid connected MMC is presented and then, the small signal state space model is obtained. MMC is a very complex MIMO system with several state variables and global control for this system is very important issue. Optimal advanced controller based on linear quadratic regulator with integral action is a very good candidate for controlling the AC signals and energy balancing in multi cells MMC system. The performance and validity of obtained model and designed linear controller are evaluated with non-linear model of MMC in SimPower System toolbox/Matlab. Simulation results are verified the excellent performance of the proposed approach in the transient and steady state operational conditions.

  • Adaptive droop for primary control in MTDC networks with energy storage

     Gavriluta, Catalin; Candela Garcia, Jose Ignacio; Luna Alloza, Alvaro; Rocabert Delgado, Joan; Rodriguez Cortes, Pedro
    European Conference on Power Electronics and Applications
    p. 1-9
    DOI: 10.1109/EPE.2013.6631976
    Presentation's date: 2013-09-06
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Multi-terminal DC (MTDC) systems are drawing a lot of interest lately in applications related to distributed generation, especially in those that integrate wind or PV systems together with energy storage. This paper proposes an improved strategy for the primary control of MTDC integrating energy storage (ES) units. The concept is based on the combination of a droop control method and dc-bus signaling in order to provide a generic approach to be used as basis for a hierarchical control structure in a multi-point DC-bus system. The proposed method considers the State of Charge (SoC) of the energy storage system at the primary control level, yielding a surface characteristic for a droop control that depends both on the SoC and the dc bus voltage. Finally, a method for designing and tuning the system is proposed and analyzed theoretically and through simulations and experiments on a 10kVA system with energy storage.

    Multi-terminal DC (MTDC) systems are drawing a lot of interest lately in applications related to distributed generation, especially in those that integrate wind or PV systems together with energy storage. This paper proposes an improved strategy for the primary control of MTDC integrating energy storage (ES) units. The concept is based on the combination of a droop control method and dc-bus signaling in order to provide a generic approach to be used as basis for a hierarchical control structure in a multi-point DC-bus system. The proposed method considers the State of Charge (SoC) of the energy storage system at the primary control level, yielding a surface characteristic for a droop control that depends both on the SoC and the dc bus voltage. Finally, a method for designing and tuning the system is proposed and analyzed theoretically and through simulations and experiments on a 10kVA system with energy storage.

  • Design of the LCL+trap filter for the two-level VSC installed in a large-scale wave power plant

     Mir Cantarellas, Antonio; Rakhshani, Elyas; Remón, D.; Rodriguez Cortes, Pedro
    IEEE Annual International Energy Conversion Congress and Exhibition for the Asia/Pacific
    p. 707-712
    DOI: 10.1109/ECCE.2013.6646771
    Presentation's date: 2013-09
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper presents a methodology for designing the link passive filter of the power converters installed in a multi-megawatt wave power plant. Such filter is based on the superposition of both LCL and trap filter configurations with the purpose of achieving enhanced grid interaction of a two-level voltage source converter. The LCLTrap filter design is highly dependent on the electrical network characteristics; hence the distribution system of the plant is introduced in the paper to take into account its effects on the tuning parameters. The proposed LCLtrap filter topology arises as a successful alternative solution for the conventional LCL filter topology, thanks to its improved filtering capability while ensuring a reduced filter size. The validation of the proposed filter performance is evaluated in simulation by performing a comparative analysis between the LCLtrap and the LCL filters when operate in a wave farm application.

    This paper presents a methodology for designing the link passive filter of the power converters installed in a multi-megawatt wave power plant. Such filter is based on the superposition of both LCL and trap filter configurations with the purpose of achieving enhanced grid interaction of a twolevel voltage source converter. The LCL+Trap filter design is highly dependent on the electrical network characteristics; hence the distribution system of the plant is introduced in the paper to take into account its effects on the tuning parameters. The proposed LCL+trap filter topology arises as a successful alternative solution for the conventional LCL filter topology, thanks to its improved filtering capability while ensuring a reduced filter size. The validation of the proposed filter performance is evaluated in simulation by performing a comparative analysis between the LCL+trap and the LCL filters when operate in a wave farm application.

  • A hierarchical control structure for multi-terminal VSC-based HVDC grids with GVD characteristics

     Rouzbehi, Kumars; Miranian, Arash; Candela Garcia, Jose Ignacio; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    IEEE International Conference on Renewable Energy Research and Applications
    Presentation's date: 2013-10-20
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper presents a hierarchical control structure for Multi terminal HVDC grids. The hierarchical control structure is inspired by the three-layer control structure of largescale AC power systems and it is divided into primary, secondary and tertiary control. This structure permits to create an easy interaction between power dispatch and the lower controllers. Moreover, a generalized voltage droop (GVD) characteristic is also proposed which facilitates control issues inside the Multi terminal HVDC grids. In the proposed control structure, the coefficients of the GVD characteristics are set based on the solution of a DC power flow algorithm, executed in the secondary control level.

  • Control of PV generation systems using the synchronous power controller

     Rodriguez Cortes, Pedro; Candela Garcia, Jose Ignacio; Luna Alloza, Alvaro
    IEEE Energy Conversion Congress and Exposition
    p. 993-998
    DOI: 10.1109/ECCE.2013.6646811
    Presentation's date: 2013-09
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The high penetration of distributed generation, as PV or wind power, has forced the Transmission System Operators (TSOs) to set restrictive requirements for the operation of such systems. As it can be extracted from the forthcoming grid codes drafts, the future distributed generation systems will be requested to have the equivalent performance of a synchronous generator, which is seen from the TSOs as the only solution if a massive integration of renewable in the electrical network should be achieved. In this paper a method for controlling PV grid connected power converters as a synchronous generator, namely Synchronous Power Controller (SPC), is presented. As a difference with previous works this method permits to take advantage of emulating the synchronous behavior meanwhile it is able to get rid of its drawbacks. The main concept of the SPC, as well as some simulation and experimental results will be shown in this paper considering a PV power plant as a study case.

    The high penetration of distributed generation, as PV or wind power, has forced the Transmission System Operators (TSOs) to set restrictive requirements for the operation of such systems. As it can be extracted from the forthcoming grid codes drafts, the future distributed generation systems will be requested to have the equivalent performance of a synchronous generator, which is seen from the TSOs as the only solution if a massive integration of renewable in the electrical network should be achieved. In this paper a method for controlling PV grid connected power converters as a synchronous generator, namely Synchronous Power Controller (SPC), is presented. As a difference with previous works this method permits to take advantage of emulating the synchronous behavior meanwhile it is able to get rid of its drawbacks. The main concept of the SPC, as well as some simulation and experimental results will be shown in this paper considering a PV power plant as a study case.

  • Comprehensive analogy between conventional AC grids and DC grids characteristics

     Rouzbehi, Kumars; Gavriluta, Catalin; Candela Garcia, Jose Ignacio; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 2004-2010
    DOI: 10.1109/IECON.2013.6699439
    Presentation's date: 2013-11-13
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The high penetration of renewable energy resources, such as wind and photovoltaic, as well as the development of power electronics devices play an important role in the development of DC grids. However, the evolution of DC-systems from point-to-point connections to `Multi-terminal¿ DC (MTDC) networks is not so straight forward. At the current moment there is a large gap in the literature concerning the dynamics, control and operation of MTDC networks. On the other hand, conventional AC networks have been studied exhaustively in the past decades providing for a rich inspiration source. In this paper we are going to establish a comprehensive analogy between the characteristics of conventional AC grids and the emerging DC grids. The key similarities and differences between the two types of grids are identified in an attempt to better understand the characteristics and behavior of DC grids. In the end, the extent to which concepts like planning for operation and control of AC grids can be conveniently extrapolated to DC grids is evaluated.

    The high penetration of renewable energy resources, such as wind and photovoltaic, as well as the development of power electronics devices play an important role in the development of DC grids. However, the evolution of DC-systems from point-to-point connections to ‘Multi-terminal’ DC (MTDC) networks is not so straight forward. At the current moment there is a large gap in the literature concerning the dynamics, control and operation of MTDC networks. On the other hand, conventional AC networks have been studied exhaustively in the past decades providing for a rich inspiration source. In this paper we are going to establish a comprehensive analogy between the characteristics of conventional AC grids and the emerging DC grids. The key similarities and differences between the two types of grids are identified in an attempt to better understand the characteristics and behavior of DC grids. In the end, the extent to which concepts like planning for operation and control of AC grids can be conveniently extrapolated to DC grids is evaluated.

  • Design of AC-DC power converters with LCL + tuned trap line filter using Si IGBT and SiC MOSFET modules

     Piasecki, S.; Mir Cantarellas, Antonio; Rabkowski, J.; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 5957-5962
    DOI: 10.1109/IECON.2013.6700112
    Presentation's date: 2013-11-13
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper presents a method for improving the design procedure of AC-DC power converters for power generation applications. The proposed methodology is based on selection of the most convenient configuration, in terms of switching frequency and design of the line filter, in order to minimize the overall losses in the system. In this work two types of semiconductor devices are considered: silicon IGBT and silicon carbide MOSFET for the design of a 100 kVA system, and they performance is compared. The AC-DC converter parameters, the design methodology and preliminary simulation results for representatives of Si IGBT and SiC MOSFET modules are presented.

  • Identification and local linear control of a DC-DC buck converter using local model networks

     Rouzbehi, Kumars; Miranian, Arash; Rakhshani, Elyas; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    IEEE International Conference on Renewable Energy Research and Applications
    Presentation's date: 2013-10-20
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • A novel approach for voltage control of multi-terminal DC grids with offshore wind farms

     Rouzbehi, Kumars; Miranian, Arash; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    IEEE Annual International Energy Conversion Congress and Exhibition for the Asia/Pacific
    p. 965-970
    DOI: 10.1109/ECCE-Asia.2013.6579223
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper proposes a novel control strategy in multi-terminal DC (MTDC) grids with offshore wind generation based on the idea of generalized voltage droop (GVD). In the proposed strategy, the GVD characteristics are assigned to the voltage-regulating converter station, enhancing their control maneuverability and enabling them to perform necessary DC voltage control and power sharing tasks. By adjusting the coefficients of the corresponding GVD characteristic, a converter station can be operated in three operating modes, namely (1) fixed active power control mode, (2) conventional voltage droop control mode or (3) fixed DC voltage control mode. Results of simulations on a test four-terminal DC grid including two offshore wind farm and two AC grids show the capabilities of the proposed control strategy. Moreover, simulation results confirmed stable operation of the GVD control in transition from one operating mode to another.

    This paper proposes a novel control strategy in multi-terminal DC (MTDC) grids with offshore wind generation based on the idea of generalized voltage droop (GVD). In the proposed strategy, the GVD characteristics are assigned to the voltage-regulating converter station, enhancing their control maneuverability and enabling them to perform necessary DC voltage control and power sharing tasks. By adjusting the coefficients of the corresponding GVD characteristic, a converter station can be operated in three operating modes, namely (1) fixed active power control mode, (2) conventional voltage droop control mode or (3) fixed DC voltage control mode. Results of simulations on a test four-terminal DC grid including two offshore wind farm and two AC grids show the capabilities of the proposed control strategy. Moreover, simulation results confirmed stable operation of the GVD control in transition from one operating mode to another.

  • PSO-based LQR controller for multi modular converters

     Rakhshani, Elyas; Mir Cantarellas, Antonio; Remón, D.; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    IEEE Annual International Energy Conversion Congress and Exhibition for the Asia/Pacific
    p. 1023-1027
    DOI: 10.1109/ECCE-Asia.2013.6579233
    Presentation's date: 2013-06
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    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 quadratic-performance 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.

    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, Alvaro; Rodriguez Cortes, Pedro
    IEEE Annual International Energy Conversion Congress and Exhibition for the Asia/Pacific
    p. 481-486
    DOI: 10.1109/ECCE-Asia.2013.6579140
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    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, the control of the converter is introduced with the purpose of validating the grid connection compliance of the entire power processing system.

    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, the control of the converter is introduced with the purpose of validating the grid connection compliance of the entire power processing system.

  • Optimized control of multi-terminal DC GridsUsing particle swarm optimization

     Rouzbehi, Kumars; Miranian, Arash; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    European Conference on Power Electronics and Applications
    p. 1-9
    DOI: 10.1109/EPE.2013.6634326
    Presentation's date: 2013-09-06
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper addresses the important issue of Multi-Terminal DC (MTDC) grid control strategy based on the particle swarm optimization (PSO) technique. The MTDC grid is controlled by the concept of vector control, in which the AC currents and voltages are transformed into the rotating directquadrature (d-q) reference quantities which are subsequently used for decoupled control of the active and reactive powers as well as the DC and AC voltages. The paper employs an efficient PSO algorithm for optimal tuning of the controllers¿ parameters in an MTDC grid. In addition, voltage droop control scheme is utilized to ensure the balance of active power within the MTDC grid. Simulation results that has obtained through detailed modeling of a four-terminal DC grid, demonstrate the efficiency of the proposed approach. Comparison to controllers optimized by genetic algorithm (GA) also confirmed the favorable performance of the proposed PSO-tuned controllers.

    This paper addresses the important issue of Multi-Terminal DC (MTDC) grid control strategy based on the particle swarm optimization (PSO) technique. The MTDC grid is controlled by the concept of vector control, in which the AC currents and voltages are transformed into the rotating directquadrature (d-q) reference quantities which are subsequently used for decoupled control of the active and reactive powers as well as the DC and AC voltages. The paper employs an efficient PSO algorithm for optimal tuning of the controllers’ parameters in an MTDC grid. In addition, voltage droop control scheme is utilized to ensure the balance of active power within the MTDC grid. Simulation results that has obtained through detailed modeling of a four-terminal DC grid, demonstrate the efficiency of the proposed approach. Comparison to controllers optimized by genetic algorithm (GA) also confirmed the favorable performance of the proposed PSO-tuned controllers.

  • A generalized voltage droop strategy for control of multi-terminal DC grids

     Rouzbehi, Kumars; Miranian, Arash; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    IEEE Energy Conversion Congress and Exposition
    p. 59-64
    DOI: 10.1109/ECCE.2013.6646681
    Presentation's date: 2013-09
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper proposes a generalized voltage droop (GVD) control strategy for control and power sharing in voltage source converter (VSC)-based multi-terminal DC (MTDC) grids. In the proposed approach, the conventional voltage droop characteristics of voltage-regulating VSC stations are replaced by the GVD characteristics. The proposed GVD control strategy can be operated in three different control modes including conventional voltage droop control, fixed active power control and fixed DC voltage control by proper adjustment of the GVD characteristics of the voltage-regulating converters. The proposed strategy improves the control and power-sharing capabilities of the conventional voltage droop, and enhances its maneuverability. Simulation results, obtained by detailed modeling in a four-terminal high voltage DC grid demonstrated the efficacy of the proposed approach and its flexibility in active power sharing. Moreover, based on the obtained results, switching between operating mode of the GVD control approach does not results in oscillations of the active powers flowing inside the MTDC grids.

    This paper proposes a generalized voltage droop (GVD) control strategy for control and power sharing in voltage source converter (VSC)-based multi-terminal DC (MTDC) grids. In the proposed approach, the conventional voltage droop characteristics of voltage-regulating VSC stations are replaced by the GVD characteristics. The proposed GVD control strategy can be operated in three different control modes including conventional voltage droop control, fixed active power control and fixed DC voltage control by proper adjustment of the GVD characteristics of the voltage-regulating converters. The proposed strategy improves the control and power-sharing capabilities of the conventional voltage droop, and enhances its maneuverability. Simulation results, obtained by detailed modeling in a four-terminal high voltage DC grid demonstrated the efficacy of the proposed approach and its flexibility in active power sharing. Moreover, based on the obtained results, switching between operating mode of the GVD control approach does not results in oscillations of the active powers flowing inside the MTDC grids.

  • Grid connection control of VSC-based high power converters for wave energy applications

     Mir Cantarellas, Antonio; Rakhshani, Elyas; Remón, D.; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 5092-5097
    DOI: 10.1109/IECON.2013.6699961
    Presentation's date: 2013-11-13
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Control of grid-connected power converters based on a virtual admittance control loop

     Rodriguez Cortes, Pedro; Candela Garcia, Jose Ignacio; Citro, Costantino; Rocabert Delgado, Joan; Luna Alloza, Alvaro
    European Conference on Power Electronics and Applications
    DOI: 10.1109/EPE.2013.6634621
    Presentation's date: 2013-09-06
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The connection of electronic power converters to the electrical network is increasing mainly due to massive integration of renewable energy systems. However, the electrical dynamic performance of these converters does not match the behavior of the network, which is mainly formed by generation facilities based on big synchronous generation systems. Depending on the desired electrical operation mode different control structures can be implemented in the converters in order to get adapted with the grid conditions. However, changing between different control structures and operation is not an optimal solution, as the resulting system results complex and is not highly robust. As an alternative, this paper presents a new control technique for grid connected power converters based on the concept of virtual admittance. The proposed control permits to emulate the electrical performance of generation facilities based on classical synchronous generators with a power converter, with no need of implementing different control structures, giving rise to a system that provides a friendly and robust operation with the network.

    The connection of electronic power converters to the electrical network is increasing mainly due to massive integration of renewable energy systems. However, the electrical dynamic performance of these converters does not match the behavior of the network, which is mainly formed by generation facilities based on big synchronous generation systems. Depending on the desired electrical operation mode different control structures can be implemented in the converters in order to get adapted with the grid conditions. However, changing between different control structures and operation is not an optimal solution, as the resulting system results complex and is not highly robust. As an alternative, this paper presents a new control technique for grid connected power converters based on the concept of virtual admittance. The proposed control permits to emulate the electrical performance of generation facilities based on classical synchronous generators with a power converter, with no need of implementing different control structures, giving rise to a system that provides a friendly and robust operation with the network.

  • Voltage-sensor-less synchronization to unbalanced grids by frequency-adaptive virtual flux estimation

     Suul, Jon Are; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro; Undeland, Tore
    IEEE transactions on industrial electronics
    Vol. 59, num. 7, p. 2910-2923
    DOI: 10.1109/TIE.2011.2168793
    Date of publication: 2012-07
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper proposes a simple method for inherently frequency-adaptive virtual flux (VF) estimation intended for voltage-sensor-less grid synchronization and control of voltage source converters. The frequency-adaptive characteristics are obtained by using a second-order generalized integrator configured as a quadrature signal generator (SOGI-QSG) with the grid frequency as an explicit input variable. It is also shown how the properties of VF estimation based on SOGI-QSGs can be utilized to achieve a simple and effective synchronization technique that integrates frequency-adaptive bandpass filtering, VF estimation, and symmetrical component sequence separation into one operation. This new method avoids cascaded delays of VF estimation and sequence separation and is labeled as dual SOGI-based VF (DSOGI-VF) estimation since it is based on two parallel SOGI-QSGs. The properties and performance of the DSOGI-VF estimation are analyzed in comparison to conventional configurations of VF estimation and sequence separation, demonstrating that it is a simpler structure with improved dynamic response. In fact, similar response time as for grid synchronization based on voltage measurements is achieved. The operation and performance of the proposed DSOGI-VF estimation method have been verified by laboratory experiments in a small-scale converter setup.

  • Multilevel-clamped multilevel converters (MLC2)

     Rodriguez Cortes, Pedro; D. Bellar, maria; Muñoz Aguilar, Raul Santiago; Busquets Monge, Sergio; Blaabjerg, Frede
    IEEE transactions on power electronics
    Vol. 27, num. 3, p. 1055-1060
    DOI: 10.1109/TPEL.2011.2172224
    Date of publication: 2012-03
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This letter introduces a new series of multilevel (ML) converters based on the ML clamping concept. By applying this technique, a ML clamping unit (MCU) conveys additional levels for synthesizing the output waveforms of a diode-clampedML dc– ac power converter. The basic building block of the ML clamping scheme is the ML clamping cell, which is composed of a pair of dc sources associated with one single-pole/triple-throw type of switch arrangement. The number of series-connected ML-clamping cells will set the number of levels of the synthesized waveform. By depending on the MCU arrangements, different converter configurations can be derived, namely, the common clamping and the modular types. Both approaches can be accomplished by employing classical three-level neutral-point-clamped (NPC) technology. Thus, the overall structure of the resultant converter is kept simple, wherein the number of parts count can be reduced, when compared with conventional NPC counterparts. In this letter, emphasis is given on the common clamping converter configuration. The attractiveness of the proposed ML concept is evidenced by conducting a comparative cost analysis. Experimental results are presented as a practicality proof of the proposed ML power converter.

  • A generalized compensation theory for active filters based on mathematical optimization in ABC frame

     Garces Correa, A.; Molinas Cabrera, Marta; Rodriguez Cortes, Pedro
    Electric power systems research
    Vol. 90, p. 1-10
    DOI: 10.1016/j.epsr.2012.03.011
    Date of publication: 2012-09
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Negative Sequence Current Control in Wind Power Plants With VSC-HVDC Connection

     Chaudhary, S. K.; Teodorescu, Remus; Rodriguez Cortes, Pedro; Kjaer, Philip Carne; Gole, A. M.
    IEEE Transactions on Sustainable Energy
    Vol. 3, num. 3, p. 535-544
    DOI: 10.1109/TSTE.2012.2191581
    Date of publication: 2012-07
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Control of power converters in AC microgrids

     Rocabert Delgado, Joan; Luna Alloza, Alvaro; Blaabjerg, Frede; Rodriguez Cortes, Pedro
    IEEE transactions on power electronics
    Vol. 27, num. 11, p. 4734-4749
    DOI: 10.1109/TPEL.2012.2199334
    Date of publication: 2012
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Enhanced decoupled double synchronous reference frame current controller for unbalanced grid-voltage conditions

     Reyes, M.; Rodriguez Cortes, Pedro; Vazquez, S.; Luna Alloza, Alvaro; Teodorescu, Remus; Carrasco, J.M.
    IEEE transactions on power electronics
    Vol. 27, num. 9, p. 3934-3943
    DOI: 10.1109/TPEL.2012.2190147
    Date of publication: 2012
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In the last few years, restrictive grid codes have arisen to ensure the performance and stability of electrical networks, which experience amassive integration of renewable energy sources and distributed generation systems that are normally connected to the grid through electronic power converters. In these codes, the injection of positive- and negative-sequence current components becomes necessary for fulfilling, among others, the low-voltage ride-through requirements during balanced and unbalanced grid faults. However, the performance of classical dq current controllers, applied to power converters, under unbalanced grid-voltage conditions is highly deficient, due to the unavoidable appearance of current oscillations. This paper analyzes the performance of the double synchronous reference frame controller and improves its structure by adding a decoupling network for estimating and compensating the undesirable current oscillations. Experimental results will demonstrate the validity of the proposed decoupled DSRF controller

  • Power capability investigation based on electrothermal models of press-pack IGBT three-level NPC and ANPC VSCs for multimegawatt wind turbines

     Senturk, Osman S.; Helle, Lars; Rodriguez Cortes, Pedro; Munk-Nielsen, Stig; Teodorescu, Remus
    IEEE transactions on power electronics
    Vol. 27, num. 7, p. 3195-3206
    DOI: 10.1109/TPEL.2011.2182661
    Date of publication: 2012-07
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Wind turbine power capability is an essential set of data for both wind turbine manufacturers/operators and transmission system operators since the power capability determines whether a wind turbine is able to fulfill transmission system reactive power requirements and how much it is able to provide reactive power support as an ancillary service. For multimegawatt full-scale wind turbines, power capability depends on converter topology and semiconductor switch technology. As power capability limiting factors, switch current, semiconductor junction temperature, and converter output voltage are addressed in this study for the three-level neutral-point-clamped voltage source converter (3L-NPC-VSC) and 3L Active NPC VSC (3L-ANPC-VSC) with press-pack insulated gate bipolar transistors employed as a gridside converter. In order to investigate these VSCs’ power capabilities under various operating conditions with respect to these limiting factors, a power capability generation algorithm based on the converter electrothermal model is developed. Built considering the VSCs’ operation principles and physical structure, the model is validated by a 2MV·A single-phase 3L-ANPC-VSC test setup. The power capability investigations regarding a sample grid code’s reactive power requirement showthat 3L-ANPC-VSC results in 32% better power capability than 3L-NPC-VSC at the switching frequency of 1050 Hz. Furthermore, 3L-ANPC-VSC with 57% higher switching frequency (1650 Hz) and 33% smaller switching ripple filter can yield close power capability compared to 3L-NPC-VSC with 1050 Hz.

  • Design and analysis of a slope voltage control for a DFIG wind power plant

     Martinez, J.; Kjaer, Philip Carne; Rodriguez Cortes, Pedro; Teodorescu, Remus
    IEEE transactions on energy conversion
    Vol. 27, num. 1, p. 11-20
    DOI: 10.1109/TEC.2011.2170197
    Date of publication: 2012-03
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper addresses a detailed design of a wind power plant and turbine slope voltage control in the presence of communication delays for a wide short-circuit ratio range operation. The implemented voltage control scheme is based upon the secondary voltage control concept, which offers fast response to grid disturbances, despite the communication delays, i.e., this concept is based on a primary voltage control, located in the wind turbine, which follows an external voltage reference sent by a central controller, called secondary voltage control, which is controlling the voltage at the point of connection with the grid. The performance has been tested using PSCAD/EMTDC program. The plant layout used in the simulations is based on an installed wind power plant, composed of 23 doubly fed generator wind turbines. The resulting performance is evaluated using a compilation of grid code voltage control requirements. The results show that fast response to grid disturbances can be achieved using the secondary voltage control scheme, and the fulfillment of the design requirements can be extended for a wide range of short-circuit ratios.

  • Evaluation of storage energy requirements for constant production in PV power plants

     Beltrán San Segundo, Héctor; Bilbao, Endika; Belenguer, Enrique; Etxeberria Otadui, Ion; Rodriguez Cortes, Pedro
    IEEE transactions on industrial electronics
    Vol. 60, num. 3, p. 1225-1234
    DOI: 10.1109/TIE.2012.2202353
    Date of publication: 2012-03-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper analyzes the minimum energy capacity ratings that an energy-storage (ES) system should accomplish in order to achieve a defined constant power production in a photovoltaic (PV) power plant. ES is a key issue for the further integration of intermittent and stochastic renewable energy sources, which are not currently dispatchable due to their dependence on real-time weather conditions, as is the case of PV technology. This paper proposes and describes an energy management strategy (EMS) for operating PV power plants with ES in the future. The goal of this EMS is to endow these power plants with a constant production that can be controlled and hence traded on electricity markets. This paper presents simulated results on the percentage of time throughout the year during which a large-scale PV+ES plant operates properly with different ES ratings and according to different configurations of this EMS. Finally, a test bench was developed, and experimental results validating this EMS were obtained

  • A stationary reference frame grid synchronization system for three-phase grid-connected power converters under adverse grid conditions

     Rodriguez Cortes, Pedro; Luna Alloza, Alvaro; Muñoz Aguilar, Raul Santiago; Etxebarría, Ion; Teodorescu, Remus; Blaabjerg, Frede
    IEEE transactions on power electronics
    Vol. 27, num. 1, p. 99-112
    DOI: 10.1109/TPEL.2011.2159242
    Date of publication: 2012-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Grid synchronization algorithms are of great importance in the control of grid-connected power converters, as fast and accurate detection of the grid voltage parameters is crucial in order to implement stable control strategies under generic grid conditions. This paper presents a new grid synchronization method for three-phase three-wire networks, namely dual second-order generalized integrator (SOGI) frequency-locked loop. The method is based on two adaptive filters, implemented by using a SOGI on the stationary αβ reference frame, and it is able to perform an excellent estimation of the instantaneous symmetrical components of the grid voltage under unbalanced and distorted grid conditions. This paper analyzes the performance of the proposed synchronization method including different design issues. Moreover, the behavior of the method for synchronizing with highly unbalanced grid is proven by means of simulation and experimental results, demonstrating its excellent performance.

  • Virtual-Flux-Based Voltage-Sensor-Less Power Control for Unbalanced Grid Conditions

     Suul, Jon Are; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro; Undeland, Tore
    IEEE transactions on power electronics
    Vol. 27, num. 9, p. 4071-4087
    DOI: 10.1109/TPEL.2012.2190301
    Date of publication: 2012-09
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • CONTROL INTERACTIVO CON RED ELECTRICA DE PLANTA FV DE GENERACION CON ALMACENAMIENTO DE ENERGIA

     Luna Alloza, Alvaro; Jornet Alvarez, Atanasi; Aldabas Rubira, Emiliano; Rodriguez Mondelo, Pedro Manuel; Rodriguez Cortes, Pedro
    Competitive project

     Share

  • Identification and maximum power point tracking of photovoltaic generation by a local neuro-fuzzy model

     Rouzbehi, Kumars; Miranian, Arash; Luna Alloza, Alvaro; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 1019-1024
    DOI: /ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6388581
    Presentation's date: 2012-10-25
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    With the rapid proliferation of the DC distribution systems, special attentions are paid to the photovoltaic (PV) generations. This paper addresses the problem of maximum power point tracking (MPPT) for PV systems using a local neuro fuzzy (LNF) network and steepest descent (SD) optimization algorithm. The proposed approach, termed LNF + SD, first identifies a valid an accurate model for the PV system using the LNF network and through measurement data. Then the identified PV model is used for MPPT by SD optimization algorithm. The salient modeling abilities of the proposed LNF network results in a reliable and dependable PV model which takes voltage, temperature and insolation variations into account. The proposed approach is evaluated using several identification and MPPT simulations. The simulation results showed the accuracy of the LNF network in modeling of PV systems. Furthermore, simulations carried out for assessment of the MPPT performance during insolation transients demonstrated the high efficiency of the proposed LNF + SD approach for MPPT applications. Performance of the proposed method MPPT, while the PV array was supplying loads through DC-DC converters was also analyzed. Comparisons to the perturb-and-observe (P&O) and fuzzy logic methods revealed the superiority of the proposed approach

  • TECCIT12-1-0009-10 - Pla de transferencia tecnologica pttu de la Univeristat Politècnica de Catalunya

     Rodriguez Cortes, Pedro; Luna Alloza, Alvaro; Hermoso Costa, Juan Ramon; Candela Garcia, Jose Ignacio; Rocabert Delgado, Joan; Muñoz Aguilar, Raul Santiago; Herrera Arias, Lidia
    Competitive project

     Share

  • Control Interactivo con la REd Eléctrica de Plantas FV de Generación que Incluyan Almacenamiento de Energía (ENE2011-29041-C02-01/ALT, sub-proyecto ENE2011-29041-C02-00/ALT)

     Aldabas Rubira, Emiliano; Rodriguez Cortes, Pedro; Luna Alloza, Alvaro; Jornet Alvarez, Atanasi; Beltrán San Segundo, Héctor
    Competitive project

     Share

  • Application of imperialist competitive algorithm to design an optimal controller for LFC problem

     Rakhshani, Elyas; Luna Alloza, Alvaro; Rouzbehi, Kumars; Rodriguez Cortes, Pedro
    Annual Conference of the IEEE Industrial Electronics Society
    p. 1223-1227
    DOI: /ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6388596
    Presentation's date: 2012-10-25
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    A novel optimization algorithm is presented to improve the design of optimal controllers for load frequency control problem. This algorithm is applied for two area LFC system with using an output feedback controller. In the practical power system, access to some of the state variables in LFC system is limited and measuring is also impossible. So an optimal output feedback controller with a practical viewpoint is proposed. The optimal control law is determined by minimizing a performance index under the output feedback conditions leading to a coupled matrix equation. In order to solve these equations traditional methods may be used. But for more accuracy and better design for this controller, ICA algorithm is applied to find the global optimal gain matrix of the controller. Simulation results of ICA are compared with the conventional design. Comparison shows the success of ICA for design of optimal controller

  • Advanced structures for grid synchronization of power converters in distributed generation applications

     Luna Alloza, Alvaro; Rocabert Delgado, Joan; Candela Garcia, Jose Ignacio; Rodriguez Cortes, Pedro; Teodorescu, Remus; Blaabjerg, Frede
    IEEE Energy Conversion Congress and Exposition
    p. 2769-2776
    DOI: 10.1109/ECCE.2012.6342381
    Presentation's date: 2012-09-15
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The Transmission System Operators are specially concerned about the Low Voltage Ride Through requirements of distributed generation power plants. Solutions based on the installation of STATCOMs and DVRs, as well as on advanced control functionalities for the existing power converters have contributed to enhance their response under faulty and distorted scenarios, and hence to fulfill these requirements. In order to achieve satisfactory results it is necessary to count on accurate and fast grid voltage synchronization algorithms, which are able to work under unbalanced and distorted conditions. This paper analyzes and compares the synchronization capability of three advanced synchronization systems: the Decoupled Double Synchronous Reference Frame-Phase-Locked Loop, the Dual Second Order Generalized Integgrator- Phase-Locked Loop and the Three-Phase Enhanced Phase-Locked Loop, designed to work under such conditions. Its response will be analyzed with respect the synchronization needs that can be extracted from the standards