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Golestan S.,Islamic Azad University at Abadan | Monfared M.,Ferdowsi University of Mashhad | Freijedo F.D.,Gamesa Innovation and Technology | Guerrero J.M.,University of Aalborg
IEEE Transactions on Power Electronics | Year: 2013

A phase-locked loop (PLL) is a closed-loop feedback control system, which synchronizes its output signal in frequency as well as in phase with an input signal. The phase detector, the loop filter, and the voltage controlled oscillator are the key parts of almost all PLLs. Within the areas of power electronics and power systems, which are focused on in this paper, the PLLs typically employ a proportional-integral controller as the loop filter, resulting in a type-2 control system (a control system of type-N has N poles at the origin in its open-loop transfer function). Recently, some attempts have been made to design type-3 PLLs, either by employing a specific second-order controller as the loop filter, or by implementing two parallel tracking paths for the PLL. For this type of PLLs, however, the advantages and limitations are not clear at all, as the results reported in different literature are contradictory, and there is no detailed knowledge about their stability and dynamic characteristics. In this paper, different approaches to realize a type-3 PLL are examined first. Then, a detailed study of dynamics and analysis of stability, followed by comprehensive parameters design guidelines for a typical type-3 PLL are presented. Finally, to get insight into the advantages/ limitations of this type of PLLs, the performance of a well-tuned type-3 PLL is compared with a conventional synchronous reference frame PLL (which is a type-2 PLL) through extensive experimental results and some theoretical discussions. © 1986-2012 IEEE.


Golestan S.,Islamic Azad University at Abadan | Ramezani M.,Islamic Azad University at Abadan | Guerrero J.M.,University of Aalborg | Freijedo F.D.,Gamesa Innovation and Technology | Monfared M.,Ferdowsi University of Mashhad
IEEE Transactions on Power Electronics | Year: 2014

The phase-locked loops (PLLs) are probably the most widely used synchronization technique in grid-connected applications. The main challenge that is associated with the PLLs is how to precisely and fast estimate the phase and frequency, when the grid voltage is unbalanced and/or distorted. To overcome this challenge, incorporating moving average filter(s) (MAF) into the PLL structure has been proposed in some recent literature. An MAF is a linear-phase finite-impulse-response filter, which can act as an ideal low-pass filter, if certain conditions hold. The main aim of this paper is to present the control design guidelines for a typical MAF-based PLL. The paper starts with the general description of MAFs. The main challenge associated with using the MAFs is then explained, and its possible solutions are discussed. The paper then proceeds with a brief overview of the different MAF-based PLLs. In each case, the PLL block diagram description is shown, the advantages and limitations are briefly discussed, and the tuning approach (if available) is evaluated. The paper then presents two systematic methods to design the control parameters of a typical MAF-based PLL: one for the case of using a proportional-integral (PI) type loop filter (LF) in the PLL, and the other for the case of using a proportional-integral-derivative (PID) type LF. Finally, the paper compares the performance of a well-tuned MAF-based PLL when using the PI-type LF with the results of using the PID-type LF, which provides useful insights into their capabilities and limitations. © 2013 IEEE.


Golestan S.,Islamic Azad University at Abadan | Monfared M.,Ferdowsi University of Mashhad | Freijedo F.D.,Gamesa Innovation and Technology | Guerrero J.M.,University of Aalborg | Guerrero J.M.,University of Barcelona
IEEE Transactions on Industrial Electronics | Year: 2014

Control Parameters design of a three-phase synchronous reference frame phase locked loop (SRF-PLL) with a prefiltering stage (acting as the sequence separator) is not a trivial task. The conventional way to deal with this problem is to neglect the interaction between the SRF-PLL and prefiltering stage, and treat them as two separate systems. This approach, although very simple, is not optimum as the prefiltering stage and the SRF-PLL may have comparable dynamics. The aim of this paper is to develop a systematic and efficient approach to design the control parameters of the SRF-PLL with prefiltering stage. To this end, the paper first optimizes the performance of the prefiltering stage in detection of the sequence components. The paper then proceeds to reduce the interaction between the prefiltering stage and SRF-PLL, which is achieved by employing a derivative-filtered proportional-integral-derivative controller as the loop filter (instead of the commonly adopted proportional-integral controller) and arranging a pole-zero cancellation. The suggested method is simple and efficient, and is applicable to the joint operation of different sequence separation techniques and the SRF-PLL. The effectiveness of the suggested design approach is confirmed through extensive experimental results. © 1982-2012 IEEE.


Jimenez F.,Gamesa Innovation and Technology | Gomez-Lazaro E.,University of Castilla - La Mancha | Fuentes J.A.,Technical University of Cartagena | Molina-Garcia A.,Technical University of Cartagena | And 2 more authors.
Renewable Energy | Year: 2013

In a number of countries where large penetration of wind generation has been developed, the increased impact of wind energy generation on power grid operations has led to the development of grid codes, with the aim of integrating this source of energy without compromising the stability of their networks. In Spain this grid code is named the Procedure of Operation for fault ride-through capability of the Spanish national grid code -PO 12.3-. To verify the fulfillment of this grid code, it has also been defined a procedure for measuring and evaluating the response of wind turbines and wind farms submitted to voltage dips -Procedure for verification, validation and certification of the requirements of the PO 12.3 on the response of wind farms in the event of voltage dips (PVVC)-.In this paper, two-phase voltage dips that comply with the requirements of the PVVC, has been applied to a Gamesa G52 with a Dip Active Converter. The measured tests are compared with the simulation of a PSCAD model of the wind turbine to verify the fulfillment of the PVVC validation process and the results obtained are presented. © 2013 Elsevier Ltd.


Jimenez F.,Gamesa Innovation and Technology | Gomez-Lazaro E.,University of Castilla - La Mancha | Fuentes J.A.,Technical University of Cartagena | Molina-Garcia A.,Technical University of Cartagena | Vigueras-Rodriguez A.,University of Castilla - La Mancha
Wind Energy | Year: 2012

Wind turbine manufacturers are required by transmission system operators for fault ride-through capability as the penetration of wind energy in the electrical systems grows. For this reason, testing and modeling of wind turbines and wind farms are required by the national grid codes to verify the fulfillment of this capability. Therefore, wind turbine models are required to simulate the evolution of voltage, current, reactive and active power during faults. The simulation results obtained from these wind turbine models are used for verification, validation and certification against the real wind turbines measurement results, although evolution of electrical variables during the fault and its clearance is not easy to fulfill. The purpose of this paper is to show the different stages involved in the fulfillment of the procedure of operation for fault ride-through capability of the Spanish national grid code (PO 12.3) and the 'procedure for verification, validation and certification of the requirements of the PO 12.3 on the response of wind farms in the event of voltage dips'. The process has been applied to a wind farm composed of Gamesa G52 wind turbines, and the results obtained are presented. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.


Malvar J.,University of Vigo | Lopez O.,University of Vigo | Yepes A.G.,University of Vigo | Vidal A.,University of Vigo | And 3 more authors.
IEEE Transactions on Industrial Electronics | Year: 2014

The use of multiphase motor drives is an increasingly important strategy nowadays. These multiphase machines are usually modeled by a reference frame transformation to avoid the cross-coupling of variables. This transformation decomposes the original n-dimensional vector space into orthogonal subspaces. Mapping the voltage and current harmonics into the subspaces in distributed machines is important because it allows to identify which components are related to the torque and which ones just increase the machine losses. The sequence identification of each harmonic is also important in closed-loop current harmonic compensation to set the controllers. In addition, the harmonic mapping is interesting in multimotor systems to know how harmonics from one machine can affect the other machines in the system. In this paper, a simple graphical method for time harmonic subspace and sequence identification is proposed. This method is valid for symmetrical machines of any phase number n, it provides full subspace and sequence identification and it can be used in multimotor systems. Experimental results using a five- and a six-phase motor in single-drive configuration and a series-connected two-motor six-phase drive validate the proposed method. © 1982-2012 IEEE.


Golestan S.,Islamic Azad University at Abadan | Monfared M.,Ferdowsi University of Mashhad | Freijedo F.D.,Gamesa Innovation and Technology
IEEE Transactions on Power Electronics | Year: 2013

In grid-connected applications, the synchronous reference frame phase-locked loop (SRF-PLL) is a commonly used synchronization technique due to the advantages it offers such as ease of implementation and robust performance. Under ideal grid conditions, the SRF-PLL enables a fast and accurate phase/frequency detection; however, unbalanced and distorted grid conditions highly degrade its performance. To overcome this drawback, several advanced PLLs have been proposed, such as the multiple reference frame-based PLL, the dual second-order generalized integrator-based PLL, and the multiple complex coefficient filter-based PLL. In this paper, a comprehensive design-oriented study of these advanced PLLs is presented. The starting point of this study is to derive the small-signal model of the aforementioned PLLs, which simplifies the parameter design and the stability analysis. Then, a systematic design procedure to fine tune the PLLs parameters is presented. The stability margin, the transient response, and the disturbance rejection capability are the key factors that are considered in the design procedure. Finally, the experimental results are presented to support the theoretical analysis. © 1986-2012 IEEE.


Suarez J.,Gamesa Innovation and Technology
European Wind Energy Conference and Exhibition 2012, EWEC 2012 | Year: 2012

A number of methods have been tested to estimate the wind speed on a classical controller for wind turbines, focusing in the capacity of increasing power production. A robust low order polynomial approximation has been derived, based on linear aerodynamics. Three coefficients are used to provide an optimal representation of the blade behaviour in the linear aerodynamics zone. In the zone near optimal operation, where this is not a sufficient approach, corrections to these expressions have been developed representing the effect non linear behaviour. This computationally efficient expression uses five parameters and has been found to provide good results. Wind model based Kalman filtering is investigated, where an on-line calculation of the variance of the wind speed (i.e. wind turbulence) is employed as a dynamical value for the process noise. An increase in the annual energy production has been assessed for both estimators in simulation environment. The effectiveness of wind magnitude estimation depends on the turbulence model used when generating the synthetic wind: the less coherence the wind has, the more effective the estimation is. The estimation of asymmetries in the flow is investigated. A model of the blade root load as a function of up flow, misalignment and vertical and horizontal shear is employed, in combination with the magnitude estimation to provide an estimate of the wind direction.


March V.,Gamesa Innovation and Technology
IET Seminar Digest | Year: 2015

The paper presents an analysis of lightning activity in 18 wind farms located at the north of Spain based on the information from LLS during 4 years. Total number of flashes attached by wind turbines and statistical information of the peak currents to the wind turbines are obtained based on hypothesis from previous field observations. Data derived from LLS is also compared with methodology described in IEC standard and with a methodology developed by Gamesa to estimate the total number of flashes attaching to wind turbines in a wind farm. Results in this paper confirm that current IEC Method underestimates the number of direct lightning flashes to wind turbines and that a new methodology may be developed to reduce the error and uncertainty of the results. © 2015, Institution of Engineering and Technology. All rights reserved.


Segers P.,Gamesa Innovation and Technology
European Wind Energy Association Conference and Exhibition 2014, EWEA 2014 | Year: 2014

This paper summarizes the aerodynamic and aero-acoustic design work that was performed to develop the GAMESA G114 blade. This blade was primarily intended as a modular, low-cost-ofenergy extension of the GAMESA 2.0MW platform. The G114 blade outer shape was optimized for annual energy production whilst complying with noise, loads, and structural requirements. Main blade features include custom-made airfoils, a very high blade absolute thickness, optimisation using CFD and aero-acoustic design using in-house Class II noise models. Specific work was performed at the root to have inherently robust root aerodynamics, and at the tip for low noise performance. The custom made airfoils were designed concurrently taking the blade design as input. Airfoil validation was performed in the Stability Wind Tunnel at Virginia Tech, USA. The design methodology comprised of various design loops evaluating different concepts that eventually converged to the actual blade design. The final product was effectively a class A surface geometry, representing the optimum between aerodynamic efficiency and structural/manufacturing requirements, that could be used for mould making. The blade outer shape was validated in two different steps; firstly the blade was validated using a virtual prototype model which is effectively the entire machine modelled in CFD. As a second step, the blade aerodynamic design was validated in-field on two different prototypes; one in Spain and one in the US. Certified power curve measurements according to IEC 61400-12 are ongoing but the initial results show a high level of conformity between the measured and predicted power curve.

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