Browsing by Author "Villate, José Luis"
Now showing 1 - 7 of 7
Results Per Page
Sort Options
Item Connection requirements for wind farms: A survey on technical requierements and regulation(2007-10) de Alegría, Iñigo Martinez; Andreu, Jon; Martín, José Luis; Ibañez, Pedro; Villate, José Luis; Camblong, Haritza; SG; GENERALThe increase of the wind power penetration in the electrical grids of Denmark, Germany, Spain and other countries and regions is challenging the stability of the system. The subject of this paper is to review the main problems of the connection of wind farms to the grid and how the grid codes must be adapted in order to integrate wind power generation capacity without affecting the quality and stability of the grid. This paper also summarizes the grid codes that have already been modified to incorporate high levels of wind power.Item Control strategies for improving power performance of two-body heaving wave energy devices(2011) Van Den Berg, Jonathan; Ricci, Pierpaolo; Tedeschi, Elisabetta; Touzon, Imanol; Villate, José Luis; Tecnalia Research & Innovation; GENERALThis paper addresses the hydrodynamic analysis of a generalized twobody system (2B), a wave energy convertor containing a power take off (PTO) system for the purpose of energy conversion. The aim is to study the behaviour of the system and the effect of different control strategies on the power performance. For such a device, resonance can be obtained at two different modes of motion. A different version of the 2B system could be designed to modify their occurrence, for example, a system 1 for the first mode and a system 2 for the second mode. The differences in the dynamics and in energy absorption between the two systems are assessed and compared. The following methodology has been used. First we started with hydrodynamic modelling of the 2B system point absorber. The hydrodynamic models provide insight to the amplitude responses and power absorption behaviour in the frequency domain. Next these models are extended to time domain models for these devices. This allows studying and optimizing the non linear effects such as forces and damping on the PTO system. Finally the time domain model allows studying the control of the devices. Three types of control have been assessed, including passive loading, equivalent saturation control and maximum stroke control. In this study the control strategies are applied only on one sea state. Conclusions based on that analysis have been drawn in this work. However time domain models, including control strategies, allow us to estimate annual power production of 2B system by consideration of all sea states found in a wave climate.Item Fault-tolerant multilevel converter topology(2006) Ceballos, Salvador; Pou, Josep; Gabiola, Igor; Villate, José Luis; Zaragoza, Jordi; Boroyevich, Dushan; POWER ELECTRONICS AND SYSTEM EQUIPMENT; GENERALThis paper presents a modified topology of the neutral-point-clamped converter. The main change consists on adding a fourth leg, which is based on the flying-capacitor converter structure. The aim of this additional leg is to provide fault tolerance to the converter. Furthermore, during normal operation mode, this leg is able to provide a stiff neutral voltage. Consequently, the low-frequency voltage oscillations that appear in the neutral point of the standard three-level topology for some operation conditions no longer exist. As a result, the modulation strategy of the three main legs of the converter does not have to take care of voltage balance, and it can be design to achieve optimal output voltage waveforms, as well as to improve efficiency of the converter. Some simulation results are presented to show viability of this approach under both, normal operation mode and fault event. Experimental results are expected to include in the final paper.Item Fault-tolerant neutral-point-clamped converter solutions based on including a fourth resonant leg(2011-06) Ceballos, Salvador; Pou, Josep; Zaragoza, Jordi; Robles, Eider; Villate, José Luis; Martín, José Luis; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHORE; GENERALThis paper presents a new three-level topology based on the neutral-point (NP)-clamped converter. An additional leg is added to the basic topology. The main purpose of this leg is to provide the converter with fault-tolerant capabilities. In addition, during normal operation mode, the fourth leg can be used to balance the NP voltage. In this way, the low-frequency voltage oscillations that appear in the NP under some operating conditions are cancelled out effectively. As a result, the modulation strategy of the three main legs of the converter does not have to take care of the voltage balance and can focus on other aspects such as, for instance, minimizing the switching losses of the converter. However, the inclusion of the fourth leg produces some additional losses. A resonant topology is proposed to minimize the switching losses of this leg. Three different fault-tolerant solutions based on the fourth-leg topology are presented. A comparison of these topologies showing their respective advantages and drawbacks is made. Experimental results are presented to show the viability of this approach.Item Flexible and reduced modulation and simulation method for a Matrix Converter-DFIM modulator(2007) Andreu, Jon; De Alegría, Iñigo Martínez; Martín, José Luis; Ibañez, Pedro; Villate, José Luis; SG; GENERALThis paper proposes a practical way to simplify large simulation platforms. A complete model with a Matrix Converter (MC) linked to a doubly fed induction machine (DFIM) is described, proving that this kind of converter is suitable for use in power regenerative rigs. Besides contributing to the study of DFIM with MC, a fast way to describe all kinds of Space Vector Modulation (SVM) algorithms is presented. The modulator algorithm is supported theoretically and described in an S-Function of Matlab-Simulink, which reduces the design time and provides a way to implement the control code in new integrated circuits, such as FPGAs; in this sense, this paper contributes to the development of IPMs (Integrated Power Module). Platform modules have been analyzed showing the links between the entire platform (MC and a DFIM). Finally, the entire design has been verified by simulation results.Item Novel power error vector control for Wind Turbine with doubly fed induction generator(2004) De Alegría, Iñigo Mtz; Andreu, Jon; Ibañez, Pedro; Villate, José Luis; Gabiola, Igor; SG; GENERAL; POWER ELECTRONICS AND SYSTEM EQUIPMENTThis paper proposes a new control method for a doubly fed induction generator. The control is suited for variable speed operation where stator active and reactive power control is required, specially in Wind Power Generation with Variable-Speed Wind Turbine. The control is similar to DTC controllers but significantly simplifies the determination of the rotor voltage vector to be applied. The stator active and reactive power errors are directly translated into a reference vector that determines the rotor voltage vector without the need of sub-synchronous or supersynchronous operation detection or rotor flux sector detection. This control method, called Power Error Vector Control, is less complex and obtains similar results to Direct Power Control. This is supported by theoretical analysis, and verified by simulation results. A test rig is being built to experimentally test the algorithm.Item Soft-switching topology for a fault-tolerant neutral-point-clamped converter(2007) Ceballos, Salvador; Pou, Josep; Zaragoza, Jordi; Robles, Eider; Villate, José Luis; Martín, José Luis; POWER ELECTRONICS AND SYSTEM EQUIPMENT; GENERALThis paper presents a new three-level topology based on the neutral-point-clamped converter. The new topology includes a fourth leg that provides fault tolerance to the converter. Furthermore, during normal operation mode, this leg is able to provide a stiff neutral voltage. Consequently, the low-frequency voltage oscillations that appear in the neutral point of the standard three-level topology for some operation conditions no longer exist. As a result, the modulation strategy of the three main legs of the converter does not have to take care of voltage balance, and it can be design to improve the efficiency of the converter. On the other hand, the addition of a fourth leg to the converter produces additional losses. However, in order to eliminate switching losses of this leg, all the power devices commutate under zero-current or zero-voltage transitions. Some simulation results are presented to show viability of this approach under both, normal operation mode and fault event.