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In this paper, we investigate the use of monofacial PV models to simulate the production of bifacial PV systems over different albedos. Analytical and empirical models were evaluated using measured data obtained from three identical bifacial PV arrays: (1) with the backside covered by white plastic, (2) with normal albedo, and (3) with high albedo. The front-and rear-side irradiances were measured in order to integrate bifaciality of the modules into the models. The models showed good performance for non-real-time monitoring, especially under clear skies, and the analytical model was more accurate than the empirical model. The heatmap visualization technique was applied to six months of data in order to investigate the site conditions on the rear side of the modules as well as the accuracy of the models. The heatmap results of the rear- and front-sides irradiances showed that the installation conditions, such as the azimuth angles of the sun and the surrounding obstacles, had a strong impact on the energy received from the back of the modules. The heatmap results of the models validated the performance of the analytical model. The average daily errors for the analytical model were less than 1% and 3% for normal and high albedos, respectively.
Salim Bouchakour; Daniel Valencia-Caballero; Alvaro Luna; Eduardo Roman; El Boudjelthia; Pedro Rodríguez. Modelling and Simulation of Bifacial PV Production Using Monofacial Electrical Models. Energies 2021, 14, 4224 .
AMA StyleSalim Bouchakour, Daniel Valencia-Caballero, Alvaro Luna, Eduardo Roman, El Boudjelthia, Pedro Rodríguez. Modelling and Simulation of Bifacial PV Production Using Monofacial Electrical Models. Energies. 2021; 14 (14):4224.
Chicago/Turabian StyleSalim Bouchakour; Daniel Valencia-Caballero; Alvaro Luna; Eduardo Roman; El Boudjelthia; Pedro Rodríguez. 2021. "Modelling and Simulation of Bifacial PV Production Using Monofacial Electrical Models." Energies 14, no. 14: 4224.
This paper presents a proposal for potential bioelectrochemical power to gas stations. It consists of a two-level voltage source converter interfacing the electrical grid on the AC side and an electromethanogenesis based bioelectrochemical system (EMG-BES) working as a stacked module on the DC side. The proposed system converts CO2 and electrical energy into methane, using wastewater as the additional chemical energy input. This energy storage system can contribute to dampening the variability of renewables in the electrical network, provide even flexibility and grid services by controlling the active and reactive power exchanged and is an interesting alternative technology in the market of energy storage for big energy applications. The big challenge for controlling this system lays in the fact that the DC bus voltage of the converter has to be changed in order to regulate the exchanged active power with the grid. This paper presents a cascade approach to control such a system by means of combining external control loops with fast inner loops. The outer power loop, with a proportional-integral (PI) controller with special limitation values and anti-windup capability, is used to generate DC bus voltage reference. An intermediate loop is used for DC bus voltage regulation and current reference generation. A new proportional resonant controller is used to track the current reference. The proposed scheme has been validated through real-time simulation in OPAL OP4510.
Mahdi Shahparasti; Amirhossein Rajaei; Andres Tarraso; Jose Vidal Leon Romay; Alvaro Luna. Control and Validation of a Reinforced Power Conversion System for Upcoming Bioelectrochemical Power to Gas Stations. Electronics 2021, 10, 1470 .
AMA StyleMahdi Shahparasti, Amirhossein Rajaei, Andres Tarraso, Jose Vidal Leon Romay, Alvaro Luna. Control and Validation of a Reinforced Power Conversion System for Upcoming Bioelectrochemical Power to Gas Stations. Electronics. 2021; 10 (12):1470.
Chicago/Turabian StyleMahdi Shahparasti; Amirhossein Rajaei; Andres Tarraso; Jose Vidal Leon Romay; Alvaro Luna. 2021. "Control and Validation of a Reinforced Power Conversion System for Upcoming Bioelectrochemical Power to Gas Stations." Electronics 10, no. 12: 1470.
Grid-connected power converters that integrate frequency support and inertia emulation functionalities have emerged in the last years. These features are promising for renewable energy-based power generation plants, as it permits such systems to contribute to enhance the power system stability. This paper discusses about three different active power control solutions that can be applied to grid-connected converters equipped with a synchronous power controller. For each solution, the detailed analytical relationship between the control parameters and the power loop dynamics is illustrated, and the local stability and dynamics are analyzed. The analysis and validation of frequency support functionalities are particularly addressed in this study, where the results obtained in a 10-kW experiment endorse the analysis; finally permitting to conclude that the synchronous power control offers good performance in terms of inertial response and droop characteristics.
Weiyi Zhang; Andres Tarraso; Joan Rocabert; Alvaro Luna; J. Ignacio Candela; Pedro Rodriguez. Frequency Support Properties of the Synchronous Power Control for Grid-Connected Converters. IEEE Transactions on Industry Applications 2019, 55, 5178 -5189.
AMA StyleWeiyi Zhang, Andres Tarraso, Joan Rocabert, Alvaro Luna, J. Ignacio Candela, Pedro Rodriguez. Frequency Support Properties of the Synchronous Power Control for Grid-Connected Converters. IEEE Transactions on Industry Applications. 2019; 55 (5):5178-5189.
Chicago/Turabian StyleWeiyi Zhang; Andres Tarraso; Joan Rocabert; Alvaro Luna; J. Ignacio Candela; Pedro Rodriguez. 2019. "Frequency Support Properties of the Synchronous Power Control for Grid-Connected Converters." IEEE Transactions on Industry Applications 55, no. 5: 5178-5189.
Employing partial power processing (PPP) technique for quasi Z-source converter (QZSC) a new structure of the converter is presented. Using PPP technique although eliminates electrical insolation, but permits reducing voltage and current stress at the semiconductors, if compared with full power proposals. In this work, two PPP structures are discussed: A first one, similar to the basic topology, where the output voltage of the power converter is in series with the input voltage; and a second one, where the output is in series with the capacitor of the QZSC. This minor modification, which requires no extra elements, improves the power rating, voltage gain, and requires a lower transformation ratio. An experimental prototype of the proposed converter has been tested and the results are compared with other implementations, permitting to validate the theoretical analysis as well as the advantages that this proposal provides.
Shahin Honarmand; Amirhossein Rajaei; Mahdi Shahparasti; Alvaro Luna; Edris Pouresmaeil. A Modified Partial Power structure for Quasi Z-Source Converter to Improve Voltage Gain and Power Rating. Energies 2019, 12, 2139 .
AMA StyleShahin Honarmand, Amirhossein Rajaei, Mahdi Shahparasti, Alvaro Luna, Edris Pouresmaeil. A Modified Partial Power structure for Quasi Z-Source Converter to Improve Voltage Gain and Power Rating. Energies. 2019; 12 (11):2139.
Chicago/Turabian StyleShahin Honarmand; Amirhossein Rajaei; Mahdi Shahparasti; Alvaro Luna; Edris Pouresmaeil. 2019. "A Modified Partial Power structure for Quasi Z-Source Converter to Improve Voltage Gain and Power Rating." Energies 12, no. 11: 2139.
Mohamed Atef Elsaharty; Alvaro Luna; Jose Ignacio Candela; Pedro Rodriguez; Mohammed Atef Elsaharty; Ignacio Candela. A Unified Power Flow Controller Using a Power Electronics Integrated Transformer. IEEE Transactions on Power Delivery 2019, 34, 828 -839.
AMA StyleMohamed Atef Elsaharty, Alvaro Luna, Jose Ignacio Candela, Pedro Rodriguez, Mohammed Atef Elsaharty, Ignacio Candela. A Unified Power Flow Controller Using a Power Electronics Integrated Transformer. IEEE Transactions on Power Delivery. 2019; 34 (3):828-839.
Chicago/Turabian StyleMohamed Atef Elsaharty; Alvaro Luna; Jose Ignacio Candela; Pedro Rodriguez; Mohammed Atef Elsaharty; Ignacio Candela. 2019. "A Unified Power Flow Controller Using a Power Electronics Integrated Transformer." IEEE Transactions on Power Delivery 34, no. 3: 828-839.
This paper deals with the design, operation, modeling, and grid integration of bioelectrochemical systems (BES) for power-to-gas application, through an electromethanogenesis process. The paper objective is to show that BES-based power-to-gas energy storage is feasible on a large scale, showing a first approximation that goes from the BES design and operation to the electrical grid integration. It is the first study attempting to cover all aspects of a BES-based power-to-gas technology, on authors’ knowledge. Designed BES reactors were based on a modular architecture, suitable for a future scaling-up. They were operated in steady state for eight months, and continuously monitored in terms of power consumption, water treatment, and biomethane production, in order to obtain data for the following modeling activity. A black box linear model of the BES was computed by using least-square methods, and validated through comparison with collected experimental data. Afterwards, a BES stack was simulated through several series and parallel connections of reactors, in order to obtain higher power consumption and test the grid integration of a real application system. The renewable energy surplus and energy price variability were evaluated for the grid integration of the BES stack. The BES stack was then simulated as energy storage system during low energy price periods, and tested experimentally with a real time system.
Raúl Santiago Muñoz-Aguilar; Daniele Molognoni; Pau Bosch-Jimenez; Eduard Borràs; Mónica Della Pirriera; Álvaro Luna. Design, Operation, Modeling and Grid Integration of Power-to-Gas Bioelectrochemical Systems. Energies 2018, 11, 1947 .
AMA StyleRaúl Santiago Muñoz-Aguilar, Daniele Molognoni, Pau Bosch-Jimenez, Eduard Borràs, Mónica Della Pirriera, Álvaro Luna. Design, Operation, Modeling and Grid Integration of Power-to-Gas Bioelectrochemical Systems. Energies. 2018; 11 (8):1947.
Chicago/Turabian StyleRaúl Santiago Muñoz-Aguilar; Daniele Molognoni; Pau Bosch-Jimenez; Eduard Borràs; Mónica Della Pirriera; Álvaro Luna. 2018. "Design, Operation, Modeling and Grid Integration of Power-to-Gas Bioelectrochemical Systems." Energies 11, no. 8: 1947.
In renewable energy based systems Grid-Connected Voltage Source Converters (GC-VSC) are used in many applications as grid-feeding converters, which transfer the power coming from the renewable energy sources to the grid. In some cases, the operation of GC-VSC may become unstable or uncontrollable due to, among others: a grid fault or an inappropriate current-power reference, that give rise to fast electrical transients or a saturation of the controller. In this paper, an improved control scheme is proposed to enhance the controllability of GC-VSC in all these situations. This solution consists of two parts, on the one hand a new Proportional-Resonant (PR) controller with anti-windup capability to be used as current controller, and secondly a new current/power reference modifier, which defines the suitable reactive current/power reference to keep the system stable. It is worth to mention that the proposed scheme does not need information about the grid parameters as it only uses the converter current, and the voltage at the capacitors of Inductor-Capacitor (LC) output filter.
Mahdi Shahparasti; Pedro Catalán; Nurul Fazlin Roslan; Joan Rocabert; Raúl-Santiago Muñoz-Aguilar; Alvaro Luna. Enhanced Control for Improving the Operation of Grid-Connected Power Converters under Faulty and Saturated Conditions. Energies 2018, 11, 525 .
AMA StyleMahdi Shahparasti, Pedro Catalán, Nurul Fazlin Roslan, Joan Rocabert, Raúl-Santiago Muñoz-Aguilar, Alvaro Luna. Enhanced Control for Improving the Operation of Grid-Connected Power Converters under Faulty and Saturated Conditions. Energies. 2018; 11 (3):525.
Chicago/Turabian StyleMahdi Shahparasti; Pedro Catalán; Nurul Fazlin Roslan; Joan Rocabert; Raúl-Santiago Muñoz-Aguilar; Alvaro Luna. 2018. "Enhanced Control for Improving the Operation of Grid-Connected Power Converters under Faulty and Saturated Conditions." Energies 11, no. 3: 525.
Renewable Energy Source (RES)-based power plants need to control the active and reactive power at the Point of Common Connection (PCC) with the grid, in order to comply with the requirements of the Transmission System Operators (TSOs). This point is normally far away from the power converter station, and the cables and step-up transformers have a non-neglectable influence on the delivered power. In order to overcome this drawback, this paper presents a control algorithm that permits one to control remotely the power injected at the PCC, by adjusting the local controller of the Voltage Source Converters (VSCs). In this work, the synchronization with the grid is done based on the Virtual Flux (VF) concept. The results reveals that the VF estimation is able to produce a reliable estimation of the grid voltage in any point of the network, and makes it possible to calculate the necessary current reference for injecting a desired active and reactive power at a point that can be some kilometres away. In this paper the main principle for this remote power control is presented. Likewise, the simulation and experimental results will be shown in order to analyse the effectiveness of the proposed system.
Nurul Fazlin Roslan; Alvaro Luna; Joan Rocabert; Jose Ignacio Candela; Pedro Rodríguez. Remote Power Control Injection of Grid-Connected Power Converters Based on Virtual Flux. Energies 2018, 11, 488 .
AMA StyleNurul Fazlin Roslan, Alvaro Luna, Joan Rocabert, Jose Ignacio Candela, Pedro Rodríguez. Remote Power Control Injection of Grid-Connected Power Converters Based on Virtual Flux. Energies. 2018; 11 (3):488.
Chicago/Turabian StyleNurul Fazlin Roslan; Alvaro Luna; Joan Rocabert; Jose Ignacio Candela; Pedro Rodríguez. 2018. "Remote Power Control Injection of Grid-Connected Power Converters Based on Virtual Flux." Energies 11, no. 3: 488.
At the present time distributed generation systems are required to disconnect from the main grid when there is an outage. In order to fulfill this requirement photovoltaic power plants (PV) are equipped with anti-islanding algorithms, embedded in the converters controller, to avoid the island operation. However, the current trends in the development of the future electrical networks evidence that it is technically feasible and economically advantageous to keep feeding islanded systems under these situations, without cutting the power supply to the loads connected to the network. Nevertheless, commercial PV power converters are programmed as grid-feeding converters, and they are unable to work in island mode if there is not an agent forming the grid. In order to overcome this problem the Synchronous Power Controller (SPC) is presented in this paper as a suitable alternative for controlling PV inverters. As it will be further discussed this controller permits PV plants to operate seamless in grid connected and island mode, with no need of changing the control structure in any case. Moreover, the participation of SPC based power converters integrating energy storage enables other grid-feeding systems to contribute to the grid operation in island conditions. The good results achieved with the SPC in different conditions will be shown in simulations and also with experiments considering a real PV power plant combining SPC and comercial SMA converters.
Pedro Rodriguez; Costantino Citro; J. Ignacio Candela; Joan Rocabert; Alvaro Luna. Flexible Grid Connection and Islanding of SPC-Based PV Power Converters. IEEE Transactions on Industry Applications 2018, 54, 2690 -2702.
AMA StylePedro Rodriguez, Costantino Citro, J. Ignacio Candela, Joan Rocabert, Alvaro Luna. Flexible Grid Connection and Islanding of SPC-Based PV Power Converters. IEEE Transactions on Industry Applications. 2018; 54 (3):2690-2702.
Chicago/Turabian StylePedro Rodriguez; Costantino Citro; J. Ignacio Candela; Joan Rocabert; Alvaro Luna. 2018. "Flexible Grid Connection and Islanding of SPC-Based PV Power Converters." IEEE Transactions on Industry Applications 54, no. 3: 2690-2702.
Weiyi Zhang; Technical University of Catalonia; Daniel Remon; Ignacio Candela; Alvaro Luna; Pedro Rodriguez; University Loyola Andaluc la. Grid-connected converters with virtual electromechanical characteristics: experimental verification. CSEE Journal of Power and Energy Systems 2017, 3, 286 -295.
AMA StyleWeiyi Zhang, Technical University of Catalonia, Daniel Remon, Ignacio Candela, Alvaro Luna, Pedro Rodriguez, University Loyola Andaluc la. Grid-connected converters with virtual electromechanical characteristics: experimental verification. CSEE Journal of Power and Energy Systems. 2017; 3 (3):286-295.
Chicago/Turabian StyleWeiyi Zhang; Technical University of Catalonia; Daniel Remon; Ignacio Candela; Alvaro Luna; Pedro Rodriguez; University Loyola Andaluc la. 2017. "Grid-connected converters with virtual electromechanical characteristics: experimental verification." CSEE Journal of Power and Energy Systems 3, no. 3: 286-295.
This paper presents a centralized protection strategy for medium voltage dc microgrids. The proposed strategy consists of a communication-assisted fault detection method with a centralized protection coordinator and a fault isolation technique that provides an economic, fast, and selective protection by using the minimum number of dc circuit breakers. The proposed method is also supported by a backup protection that is activated if communication fails. This paper also introduces a centralized self-healing strategy that guarantees successful operation of zones that are separated from the main grid after the operation of the protection devices. Furthermore, to provide a more reliable protection, thresholds of the protection devices are adapted according to the operational modes of the microgrid and the status of distributed generators. The effectiveness of the proposed protection strategy is validated through real-time simulation studies based on the hardware in the loop approach.
Mehdi Monadi; Catalin Gavriluta; Alvaro Luna; Jose Ignacio Candela; Pedro Rodriguez. Centralized Protection Strategy for Medium Voltage DC Microgrids. IEEE Transactions on Power Delivery 2016, 32, 430 -440.
AMA StyleMehdi Monadi, Catalin Gavriluta, Alvaro Luna, Jose Ignacio Candela, Pedro Rodriguez. Centralized Protection Strategy for Medium Voltage DC Microgrids. IEEE Transactions on Power Delivery. 2016; 32 (1):430-440.
Chicago/Turabian StyleMehdi Monadi; Catalin Gavriluta; Alvaro Luna; Jose Ignacio Candela; Pedro Rodriguez. 2016. "Centralized Protection Strategy for Medium Voltage DC Microgrids." IEEE Transactions on Power Delivery 32, no. 1: 430-440.
Weiyi Zhang; Daniel Remon; Antoni M. Cantarellas; Alvaro Luna; Pedro Rodriguez. Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters. EPE Journal 2016, 26, 1 -11.
AMA StyleWeiyi Zhang, Daniel Remon, Antoni M. Cantarellas, Alvaro Luna, Pedro Rodriguez. Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters. EPE Journal. 2016; 26 (3):1-11.
Chicago/Turabian StyleWeiyi Zhang; Daniel Remon; Antoni M. Cantarellas; Alvaro Luna; Pedro Rodriguez. 2016. "Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters." EPE Journal 26, no. 3: 1-11.
The high-voltage multi-terminal dc (MTDC) systems are foreseen to experience an important development in the next years. Currently, they have appeared to be a prevailing technical and economical solution for harvesting offshore wind energy. In this study, inertia mimicry capability is added to a voltage-source converter-HVDC grid-side station in an MTDC grid connected to a weak ac grid, which can have low inertia or even operate as an islanded grid. The presented inertia mimicry control is integrated in the generalised voltage droop strategy implemented at the primary level of a two-layer hierarchical control structure of the MTDC grid to provide higher flexibility, and thus controllability to the network. Besides, complete control framework from the operational point of view is developed to integrate the low-level control of the converter stations in the supervisory control centre of the MTDC grid. A scaled laboratory test results considering the international council on large electric systems (CIGRE) B4 MTDC grid demonstrate the good performance of the converter station when it is connected to a weak islanded ac grid.
Weiyi Zhang; Kumars Rouzbehi; Alvaro Luna; Gevork B. Gharehpetian; Pedro Rodriguez. Multi‐terminal HVDC grids with inertia mimicry capability. IET Renewable Power Generation 2016, 10, 752 -760.
AMA StyleWeiyi Zhang, Kumars Rouzbehi, Alvaro Luna, Gevork B. Gharehpetian, Pedro Rodriguez. Multi‐terminal HVDC grids with inertia mimicry capability. IET Renewable Power Generation. 2016; 10 (6):752-760.
Chicago/Turabian StyleWeiyi Zhang; Kumars Rouzbehi; Alvaro Luna; Gevork B. Gharehpetian; Pedro Rodriguez. 2016. "Multi‐terminal HVDC grids with inertia mimicry capability." IET Renewable Power Generation 10, no. 6: 752-760.
This paper proposes an efficient control framework that utilizes dc-dc converters to achieve flexible power flow control in multiterminal dc (MTDC) grids. The dc-dc converter employed in this paper is connected in cascade with the dc transmission line, and is therefore named cascaded power flow controller (CPFC). In this paper, a two-layer control strategy is developed for the operation and control of voltage source converter stations and CPFC station in MTDC grids. At the primary control layer, a novel differential voltage droop control is developed, while at the secondary control layer, a modified dc power flow algorithm-employing the new CPFC framework-is implemented. The overall control strategy enables the CPFC to regulate the power flow in the dc transmission line. The primary control guarantees the transient stability of the CPFC, and the secondary control system ensures the desired steady-state operation. The proposed voltage droop control framework helps the MTDC grid to remain stable in the event of a communication failure between the primary and secondary control layers. Static analysis and dynamic simulations are performed on the CIGRE B4 dc grid test system, in order to confirm the effectiveness of the proposed control framework for power flow regulation in MTDC grids.
Kumars Rouzbehi; Jose Ignacio Candela; Alvaro Luna; Gevork B. Gharehpetian; Pedro Rodriguez. Flexible Control of Power Flow in Multiterminal DC Grids Using DC–DC Converter. IEEE Journal of Emerging and Selected Topics in Power Electronics 2016, 4, 1135 -1144.
AMA StyleKumars Rouzbehi, Jose Ignacio Candela, Alvaro Luna, Gevork B. Gharehpetian, Pedro Rodriguez. Flexible Control of Power Flow in Multiterminal DC Grids Using DC–DC Converter. IEEE Journal of Emerging and Selected Topics in Power Electronics. 2016; 4 (3):1135-1144.
Chicago/Turabian StyleKumars Rouzbehi; Jose Ignacio Candela; Alvaro Luna; Gevork B. Gharehpetian; Pedro Rodriguez. 2016. "Flexible Control of Power Flow in Multiterminal DC Grids Using DC–DC Converter." IEEE Journal of Emerging and Selected Topics in Power Electronics 4, no. 3: 1135-1144.
The increasing amount of renewable power generation systems is a challenging issue for the control and operation of the electrical networks. One of the main issues is their lack of inertia, which is becoming a greater problem as much as the share of the power plants based on traditional synchronous generators gets reduced. In this regard, the new grid codes ask these plants to provide new functionalities such as the frequency support and inertia emulation. In this paper, a synchronous power controller for grid-connected converters is proposed as a good solution for the renewable generation systems with energy storage. It provides inertia, damping, and flexible droop characteristics. Different from the faithful replication of the swing equation of synchronous machines, an alternative control structure is proposed, by which the damping and inherent droop slope can be configured independently to meet the requirements in both dynamics and frequency regulations. Analysis and experimental results are both shown to validate the proposed controller.
Weiyi Zhang; Antoni M. Cantarellas; Joan Rocabert; Alvaro Luna; Pedro Rodriguez. Synchronous Power Controller With Flexible Droop Characteristics for Renewable Power Generation Systems. IEEE Transactions on Sustainable Energy 2016, 7, 1572 -1582.
AMA StyleWeiyi Zhang, Antoni M. Cantarellas, Joan Rocabert, Alvaro Luna, Pedro Rodriguez. Synchronous Power Controller With Flexible Droop Characteristics for Renewable Power Generation Systems. IEEE Transactions on Sustainable Energy. 2016; 7 (4):1572-1582.
Chicago/Turabian StyleWeiyi Zhang; Antoni M. Cantarellas; Joan Rocabert; Alvaro Luna; Pedro Rodriguez. 2016. "Synchronous Power Controller With Flexible Droop Characteristics for Renewable Power Generation Systems." IEEE Transactions on Sustainable Energy 7, no. 4: 1572-1582.
Multi-terminal dc networks based on voltage source converters (VSC) are the latest trend in dc-systems; the interest in the area is being fueled by the increased feasibility of these systems for the large scale integration of remote offshore wind resources. Despite the active research effort in the field, at the moment, issues related to the operation and control of these networks, as well as sizing, are still uncertain. This paper intends to make a contribution in this field by analyzing the sizing of droop control for VSC together with the output capacitors. Analytical formulas are developed for estimating the voltage peaks during transients, and then it is shown how these values can be used to dimension the dc-bus capacitor of each VSC. Further on, an improved droop control strategy that attenuates the voltage oscillations during transients is proposed. The proposed methods are validated on the dc-grid benchmark proposed by the CIGRE B4 working group. Starting from the structure of the network and the power rating of the converters at each terminal, the output capacitors and the primary control layer are designed together in order to ensure acceptable voltage transients.
Catalin Gavriluta; Ignacio Candela; Costantino Citro; Alvaro Luna; Pedro Rodriguez. Design considerations for primary control in multi-terminal VSC-HVDC grids. Electric Power Systems Research 2015, 122, 33 -41.
AMA StyleCatalin Gavriluta, Ignacio Candela, Costantino Citro, Alvaro Luna, Pedro Rodriguez. Design considerations for primary control in multi-terminal VSC-HVDC grids. Electric Power Systems Research. 2015; 122 ():33-41.
Chicago/Turabian StyleCatalin Gavriluta; Ignacio Candela; Costantino Citro; Alvaro Luna; Pedro Rodriguez. 2015. "Design considerations for primary control in multi-terminal VSC-HVDC grids." Electric Power Systems Research 122, no. : 33-41.
Multiterminal dc (MTDC) systems are drawing a lot of interest lately in applications related to distributed generation, especially in those that integrate wind or photovoltaic (PV) generation with energy storage (ES). Several approaches for controlling the operation of such systems have been proposed in the literature; however, the existing structures are mainly application specific and, thus, can be still improved in order to provide a more generic approach. This paper proposes an improved primary control layer for an MTDC system. The concept is based on the combination of a droop control method and dc bus signaling in order to provide a more generic and flexible solution. In this paper, different droop characteristics are proposed for the various elements connected to the dc bus. All of them are specifically tailored around five operation bands, which depend on the dc bus voltage level. Special attention is paid to the integration of ES: the state of charge (SoC) is considered at the primary control level, yielding a surface characteristic that depends on the SoC and the dc bus voltage. The scaling of the system has been analyzed together with the proposed control strategy and the overall operation has been validated through simulations by considering a 100 kW PV system with energy storage. Experimental results were obtained on a scaled laboratory prototype rated at 10 kW.
Catalin Gavriluta; J. Ignacio Candela; Joan Rocabert; Alvaro Luna; Pedro Rodriguez. Adaptive Droop for Control of Multiterminal DC Bus Integrating Energy Storage. IEEE Transactions on Power Delivery 2015, 30, 16 -24.
AMA StyleCatalin Gavriluta, J. Ignacio Candela, Joan Rocabert, Alvaro Luna, Pedro Rodriguez. Adaptive Droop for Control of Multiterminal DC Bus Integrating Energy Storage. IEEE Transactions on Power Delivery. 2015; 30 (1):16-24.
Chicago/Turabian StyleCatalin Gavriluta; J. Ignacio Candela; Joan Rocabert; Alvaro Luna; Pedro Rodriguez. 2015. "Adaptive Droop for Control of Multiterminal DC Bus Integrating Energy Storage." IEEE Transactions on Power Delivery 30, no. 1: 16-24.
This paper proposes a hierarchical control architecture designed for an arbitrary high voltage multiterminal dc (MTDC) network. In the proposed architecture, the primary control of the MTDC system is decentralized and implemented using a generalized droop strategy. Design criteria for dimensioning the primary control parameters, including voltage limits, are offered by analyzing the transients appearing in the system. The proposed secondary control is centralized and regulates the operating point (OP) of the network so that optimal power flow (OPF) is achieved. Compared to previous works, this paper further elaborates, both analytically and through simulations, on the coordination between the primary and secondary control layers. This includes how local primary controllers have to be driven by the centralized controller in order to ensure a smooth transition to the optimal OP.
Catalin Gavriluta; Ignacio Candela; Alvaro Luna; Antonio Gomez-Exposito; Pedro Rodriguez. Hierarchical Control of HV-MTDC Systems With Droop-Based Primary and OPF-Based Secondary. IEEE Transactions on Smart Grid 2014, 6, 1502 -1510.
AMA StyleCatalin Gavriluta, Ignacio Candela, Alvaro Luna, Antonio Gomez-Exposito, Pedro Rodriguez. Hierarchical Control of HV-MTDC Systems With Droop-Based Primary and OPF-Based Secondary. IEEE Transactions on Smart Grid. 2014; 6 (3):1502-1510.
Chicago/Turabian StyleCatalin Gavriluta; Ignacio Candela; Alvaro Luna; Antonio Gomez-Exposito; Pedro Rodriguez. 2014. "Hierarchical Control of HV-MTDC Systems With Droop-Based Primary and OPF-Based Secondary." IEEE Transactions on Smart Grid 6, no. 3: 1502-1510.
This paper proposes a generalized voltage droop (GVD) control strategy for dc voltage control and power sharing in voltage source converter (VSC)-based multiterminal dc (MTDC) grids. The proposed GVD control is implemented at the primary level of a two-layer hierarchical control structure of the MTDC grid, and constitutes an alternative to the conventional voltage droop characteristics of voltage-regulating VSC stations, providing higher flexibility and, thus, controllability to these networks. As a difference with other methods, 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 adjusting the GVD characteristics of the voltage-regulating converters. Such adjustment is carried out in the secondary layer of the hierarchical control structure. The proposed strategy improves the control and power-sharing capabilities of the conventional voltage droop, and enhances its maneuverability. The simulation results, obtained by employing a CIGRE B4 dc grid test system, demonstrate the efficiency of the proposed approach and its flexibility in active power sharing and power control as well as voltage control. In these analysis, it will be also shown how the transitions between the operating modes of the GVD control does not give rise to active power oscillations in the MTDC grids.
Kumars Rouzbehi; Arash Miranian; Jose Ignacio Candela; Alvaro Luna; Pedro Rodriguez. A Generalized Voltage Droop Strategy for Control of Multiterminal DC Grids. IEEE Transactions on Industry Applications 2014, 51, 607 -618.
AMA StyleKumars Rouzbehi, Arash Miranian, Jose Ignacio Candela, Alvaro Luna, Pedro Rodriguez. A Generalized Voltage Droop Strategy for Control of Multiterminal DC Grids. IEEE Transactions on Industry Applications. 2014; 51 (1):607-618.
Chicago/Turabian StyleKumars Rouzbehi; Arash Miranian; Jose Ignacio Candela; Alvaro Luna; Pedro Rodriguez. 2014. "A Generalized Voltage Droop Strategy for Control of Multiterminal DC Grids." IEEE Transactions on Industry Applications 51, no. 1: 607-618.
The enabling of ac microgrids in distribution networks allows delivering distributed power and providing grid support services during regular operation of the grid, as well as powering isolated islands in case of faults and contingencies, thus increasing the performance and reliability of the electrical system. The high penetration of distributed generators, linked to the grid through highly controllable power processors based on power electronics, together with the incorporation of electrical energy storage systems, communication technologies, and controllable loads, opens new horizons to the effective expansion of microgrid applications integrated into electrical power systems. This paper carries out an overview about microgrid structures and control techniques at different hierarchical levels. At the power converter level, a detailed analysis of the main operation modes and control structures for power converters belonging to microgrids is carried out, focusing mainly on grid-forming, grid-feeding, and grid-supporting configurations. This analysis is extended as well toward the hierarchical control scheme of microgrids, which, based on the primary, secondary, and tertiary control layer division, is devoted to minimize the operation cost, coordinating support services, meanwhile maximizing the reliability and the controllability of microgrids. Finally, the main grid services that microgrids can offer to the main network, as well as the future trends in the development of their operation and control for the next future, are presented and discussed.
Joan Rocabert; Alvaro Luna; Frede Blaabjerg; Pedro Rodriguez. Control of Power Converters in AC Microgrids. IEEE Transactions on Power Electronics 2012, 27, 4734 -4749.
AMA StyleJoan Rocabert, Alvaro Luna, Frede Blaabjerg, Pedro Rodriguez. Control of Power Converters in AC Microgrids. IEEE Transactions on Power Electronics. 2012; 27 (11):4734-4749.
Chicago/Turabian StyleJoan Rocabert; Alvaro Luna; Frede Blaabjerg; Pedro Rodriguez. 2012. "Control of Power Converters in AC Microgrids." IEEE Transactions on Power Electronics 27, no. 11: 4734-4749.