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UPCommons - E-prints UPC Universitat Politècnica de Catalunya (78,620 recursos)
E-prints UPC cobreix dues finalitats: per una banda, és el dipòsit institucional de la UPC que recull els articles de revista, les comunicacions de congrés i els reports de recerca generats en les activitats de recerca del personal docent i investigador de la universitat; per l'altra, és una eina que permet accelerar la producció científica, allotjant versions de documents prèvies a la publicació en una revista o a les actes d’un congrés.

Ponències/Comunicacions de congressos

Mostrando recursos 1 - 20 de 342

1. Tuning of proportional resonant controllers for three phase PV power converters with LCL+trap filter - Zhang, Weiyi; Citro, Costantino; Mir Cantarellas, Antonio; Remón, D.; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
Power generation facilities based on renewable energy sources, such as PV or wind, are frequently connected to the grid through three-phase power converters. As the power of the plant increases, the design of the grid connection filters becomes critical, as a fast dynamic performance is needed while the injection of current harmonics to the network should be prevented. LCL filters, together with trap filters tuned at the switching frequency, provide a good trade-off between both needs. However, the tuning of the controllers becomes more complex as the LCL+trap filter lead to a considerably higher order system. In this paper a...

2. A hybrid power flow controller for flexible operation of multi-terminal DC grids - Rouzbehi, Kumars; Miranian, Arash; Candela García, José Ignacio; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
This paper develops a hybrid power flow controller (HPFC) to take one step forward for building future flexible DC transmission system (FDCTS). The idea for proposing HPFC is inspired by the successful operation of flexible AC transmission systems (FACTS) devices, the FDCTS includes static power electronics-based elements to provide voltage regulation, power control and load flow control in the multi-terminal DC (MTDC) grids. The HPFC, as one of the devices of the FDCTS, has a hybrid connection scheme (i.e. series-parallel) to the grid and allows power flow control through DC transmission lines by imposing a series voltage to the controlled...

3. Proposals for flexible operation of multi-terminal DC grids: introducing flexible DC transmission system (FDCTS) - Rouzbehi, Kumars; Miranian, Arash; Candela García, José Ignacio; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
The current route of achieving the ultimate plan for flawless operation and control of the multi-terminal DC (MTDC) grids can be significantly accelerated by learning from the vast and valuable experiences gained from the operation of the AC power grids for more than a century. This paper introduces concept of flexible DC transmission system (FDCTS), inspired by the successful operation of flexible AC transmission systems (FACTS), to provide voltage regulation, power control and load flow control within MTDC grids. Considering the current advancements in the field of power electronics, this paper recognizes DC-DC converters as the first element of the...

4. Optimal design of a three-phase AFPM for in-wheel electrical traction - Saavedra Ordóñez, Harold; Riba Ruiz, Jordi-Roger; Romeral Martínez, José Luis
Sinusoidally fed permanent magnet synchronous motors (PMSM) fulfill the special features required for traction motors to be applied in electric vehicles (EV). Among them, axial flux permanent magnet (AFPM) synchronous motors are especially suited for in-wheel applications. Electric motors used in such applications must meet two main requirements, i.e. high power density and fault tolerance. This paper deals with the optimal design of an AFPM for in-wheel applications used to drive an electrical scooter. The single-objective optimization process carried out in this paper is based on designing the AFPM to obtain an optimized power density while ensuring appropriate fault tolerance requirements. For this purpose a...

5. Towards fully controllable multi-terminal DC grids using flexible DC transmission systems - Rouzbehi, Kumars; Miranian, Arash; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
This paper develops a flexible DC transmission system (FDCTS) to power control and load flow control within the multi-terminal (MTDC) grids. The FDCTS include static power electronics-based elements for electric energy transmission inside a DC grid. Considering the current advancements in the field of power electronics, this paper proposes a cascaded power flow controller (CPFC) as the first element of the FDTCS for providing power control in MTDC grids. It is shown through dynamic simulations that the CPFC is able to control power flowing through a particular DC transmission line, and thus enhancing controllability in the MTDC grids.

6. Multiobjective optimization of IPM synchronous motor using response surface methodology and filtered Monte Carlo approach - Seifert, Robert; Bargalló Perpiñá, Ramón
Permanent Magnet Synchronous Motors offer high efficiency and power density besides low assembly effort and hence have been established in a wide market over the past years. Especially buried magnets enable a superior field weakening ability but require an exceptional design effort. Costly Finite Elements computations are inevitable for consideration of the occurring non-linearity and non-trivial magnet shapes. The Response Surface Methodology can reduce the number of FE runs significantly by introducing an acceptably exact second order regression model based on a few carefully chosen design samples. Instead of commonly used, but time-consuming Evolutionary Strategy methods, the Monte Carlo approach...

7. Integration of renewable generation for frequency support of HVDC/AC interconnected systems under power market scenario - Rakhshani, Elyas; Remón, D.; Mir Cantarellas, Antonio; Rouzbehi, Kumars; Rodríguez Cortés, Pedro
This paper proposes a modified model for active power/ frequency support of multi-area power system analysis that takes into account the effects of AC/DC systems under deregulated environment of the power market. The AC part of studied system is comprised of conventional generators and HVAC lines, while DC systems are related to the parts with converter station models and HVDC interconnection. Simulations performed by Matlab software demonstrate how renewable power plants can serve as conventional generators in AGC control loops under constraints determined by the market rules. This scenery is considered one of the most promising evolutions of the future...

8. Burden resistor selection in current transformers for low power applications - Conesa Roca, Alfons; Bargalló Perpiñá, Ramón; Velasco Quesada, Guillermo; Román Lumbreras, Manuel
In order to sense AC current with electric isolation in high frequency switching power converters the most simple and low cost solution is to consider a current transformer with a burden resistor. But burden resistor selection is not a simple task because involves a lot of considerations that affect the output voltage and its signal-to-noise ratio and the bandwidth of the measure. In this paper, considering the basic equations of the transformer and applying the Laplace Transformation is obtained a simple model of the current transformer interesting to select burden resistor and even to design the current transformer in case...

9. Bounded synchronization in resistive multi-terminal VSC-HVDC transmission systems - Dòria Cerezo, Arnau; Olm Miras, Josep Maria; di Bernardo, Mario; Quaglia, Massimiliano; Nuño, Emmanuel
Multi-terminal VSC-HVDC transmission is a promising solution to transport energy from the generating plants to the distribution stations, and the number and size of the corresponding power grids is expected to increase in the next years. Such a system presents challenging control problems that, so far, have been approached with classical control techniques. However, large scale systems of interconnected nodes fall within the framework of the emerging field of complex networks. This paper analyzes the stability of multi-terminal VSC-HVDC systems from a complex dynamical network perspective, and provides sufficient conditions to ensure bounded synchronization of its trajectories. The obtained results are validated via numerical simulations.

10. Intelligent voltage control in a DC micro-grid containing PV generation and energy storage - Rouzbehi, Kumars; Miranian, Arash; Candela García, José Ignacio; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
This paper proposes an intelligent control scheme for DC voltage regulationin a DC micro-grid integrating photovoltaic (PV) generation, energy storage and electric loads. The maximum power generation of the PV panel is followed using the incremental conductance (IC) maximum power point tracking (MPPT) algorithm while a high-performance local linear controller (LLC)is developed for the DC voltage control in the micro-grid.The LLC, as a data-driven control strategy, controls the bidirectional converter located between the battery and the DC micro-grid to regulate the micro-grid's voltage at the specified reference value.In order to validate the controller different simulations including variations in the load...

11. Test and simulation of lightning current distribution on a wind turbine blade - Romero Durán, David; Montanya, Joan; Vinck, Jeroen
Design of the lightning protection system (LPS) of complex wind turbine blades must take into account how current is distributed along possible paths to ground. The flow of lightning currents can result in overvoltages which in turn can ignite sparks and deposit enough energy to produces severe damages. In addition, blades include several electric circuits such as signalization, sensors and controls that need to be considered. Test and simulation results of current distribution test of a wind turbine blade are presented in this paper. The effects of the carbon laminates, conductivity and connections will be discussed.

12. A control strategy for DC-link voltage control containing PV generation and energy storage — An intelligent approach - Rouzbehi, Kumars; Miranian, Arash; Candela García, José Ignacio; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
In this paper, DC-link voltage control in DC microgrids with photovoltaic (PV) generation and battery, is addressed based on an intelligent approach. The proposed strategy is based on the modeling of the power interface, i.e. power electronic converter, located between the PV array, battery and DC bus, by use of measurement data. For this purpose, a local model network (LMN) is developed to model the converter and then a local linear control (LLC) strategy is designed based on the LMN. Simulation results on a DC microgrid demonstrates efficacy of the proposed approach.

13. Evaluation and control design of virtual-synchronous-machine-based STATCOM for grids with high penetration of renewable energy - Chi, Li; Burgos, R.; Cvetkovic, I.; Boroyevich, D.; Mili, L.; Rodríguez Cortés, Pedro
Because renewable energy sources are environment-friendly and inexhaustible, more and more said renewable energy power plants have been integrated into power grids worldwide. To compensate for their inherent variability, STATCOMs are typically installed at the point of common coupling (PCC) to help their operation by regulating the PCC voltage. However under different contingencies, PCC voltage fluctuations in magnitude and frequency may impede the STATCOM from tracking the grid frequency correctly, hence worsening its overall compensation performance, and putting at risk the operation of the power plant. Further, the virtual synchronous machine (VSM) concept has recently been introduced to control grid-connected...

14. Performance analysis of conventional PSS and fuzzy controller for damping power system oscillations - Banna, Hasan UI; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro; Cabrera Tobar, Ana; Ghorbani, Hamidreza; Ying, Shaoqing
Electro-mechanical oscillations are produced, in the machines of an interconnected power network, followed by a disturbance or due to high power transfer through weak tie lines. These oscillations should be damped as quickly as possible to ensure the reliable and stable operation of the network. To damp these oscillations different controllers, based on local or wide area signals, have been the subject of many papers. This paper presents the analysis of the performance of Conventional Power System Stabilizer (CPSS) and Fuzzy Logic Controller. Two area 14 bus symmetrical system is considered to demonstrate the performance of these controllers using Simulink/MATLAB....

15. Modeling harmonics of networks supplying nonlinear loads - Lamich Arocas, Manuel; Balcells Sendra, Josep; Corbalán Fuertes, Montserrat; Sainz Sapera, Luis; Fernandez, Cristian
This work presents the development and validation of a model for electric networks supplying nonlinear loads (NLL). The model is based on Neural Networks (NN) and its purpose is the prediction of harmonic currents sank by the loads, in case of supply impedance changes caused by the insertion or releasing of neighboring loads or by the voluntary insertion of filters to reduce such harmonic currents. The NN is trained using data obtained from several Matlab simulations and the model is validated using the same network with different supply impedances and load conditions.

16. Impacts of wind energy in-feed on power system small signal stability - Banna, Hasan UI; Luna Alloza, Álvaro; Ying, Shaoqing; Ghorbani, Hamidreza; Rodríguez Cortés, Pedro
Integration of large amount of wind energy in an interconnected power system creates concerns about secure, reliable and economical operation of the entire power system. So it becomes very necessary to investigate the impacts of wind power infeed on the dynamic behavior of the power system. This paper presents the impacts of large amount of wind power in feed on the rotor oscillatory stability. Wind turbine generator types currently employed in wind farms, optimal location of the wind farms in the interconnected power system, reliable optimal dispatch of the wind power and the degree of tie line congestion have been...

17. A proportional resonant controller tuning method for grid connected power converters with LCL+trap filter - Zhang, Weiyi; Mir Cantarellas, Antonio; Remón, D.; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
Three-phase power converters are largely employed in power generation facilities based on renewable energy sources, and these converters commonly working in grid connection mode are frequently connected to the grid through passive filters. Nowadays the need for larger power converter-based generation plants increases continuously, and LCL+trap filter arises as a solution when switching frequency is reduced due to the power increase. However, the tuning of current controllers becomes more complex as the LCL+trap filter lead to a considerably high order system. In this work a method for tuning the gains of proportional resonant current controllers for three-phase high power converters...

18. Analysis and design of virtual synchronous machine based STATCOM controller - Chi, Li; Burgos, R.; Cvetkovic, I.; Boroyevich, D.; Mili, L.; Rodríguez Cortés, Pedro
this paper extends the virtual synchronous machine (VSM) concept, recently proposed as alternative means to synchronize grid-connected inverters, by developing a VSM-based STATCOM controller operating as synchronous condenser. To this end, a mathematical model is derived and used to analyze the inherent dynamics of the VSM-based STATCOM controller, which are then used to formulate design guidelines that further detach the proposed method from the perceived physical constraints introduced by the VSM concept.

19. Enhanced control strategy for MMC-based STATCOM for unbalanced load compensation - Nieves, M.; Maza, J.M.; Mauricio, J.M.; Teodorescu, Remus; Bongiorno, M.; Rodríguez Cortés, Pedro
Modular Multilevel Converters (MMC) technology is today one of the preferred technology in HVDC and large STATCOM applications due to modularity, fault tolerance and high efficiency, but the voltage balancing becomes very challenging, especially during negative sequence current injection as required for load unbalance compensation. This paper proposes an improved balancing strategy for the delta configuration to overcome this situation based on the injection of a third harmonic zero sequence current. Simulation results have proved the effectiveness of the proposal even where different switching losses and capacitor tolerance are taken in consideration.

20. Distributed FLISR algorithm for smart grid self-reconfiguration based on IEC61850 - Koch-Ciobotaru, Cosmin; Monadi, Mehdi; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
This paper proposes a distributed algorithm for Fault Location, Isolation, and Service Restoration (FLISR) to be implemented as part of the intelligent software for controlling the operation of each circuit breaker. The paper proposes an event driven finite-state machine design that assures the self-reconfiguration of the distribution power grid when a fault occurs on a certain section of a feeder. The benefits of such an approach are first of all the modularity, as each breaker is controlled by the same algorithm and requires data exchange only with the neighboring protection devices. Secondly, by using the event driven technique, the FLISR...

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