Wind Turbine Emulator Research Articles

Comparative study of improved control strategies for DFIG in wind energy conversion systems: A dSpace real-time implementation approach

This research paper focuses on the comparison of two distinct strategies for direct power control (DPC) of a doubly fed induction generator (DFIG) in wind energy conversion systems (WECSs). The study places particular emphasis on algorithms based on low-pass filters for the estimation of stator and rotor flux, which have demonstrated good performance characteristics. Detailed theoretical analysis and implementation procedures of the proposed methods are presented. To evaluate and compare the performance of the control strategies, MATLAB/Simulink software is utilized for comprehensive analysis. The obtained results, both quantitative and qualitative, from this comparative analysis are expected to be of great interest to researchers engaged in the field of DFIG-based WECSs. Furthermore, real-time validation is conducted to demonstrate the effectiveness of the proposed control strategy, specifically focusing on the DPC approach based on stator flux estimation. A dSpace 1104 real-time card is employed and tested with a wind turbine emulator. The experimental results obtained through this validation process provide evidence of the efficiency and validity of the proposed control strategy. Overall, this research contributes to the advancement of DPC strategies for DFIG-based WECS by comparing and evaluating different control methods, providing in-depth theoretical analysis, and validating the proposed approach through real-time experimentation. The findings affirm the efficiency and effectiveness of the proposed control strategy, further establishing its value in practical applications.

Comparative study of wind turbine emulator control using an asynchronous motor: IRFOC and DTC

Comparative study of wind turbine emulator control using an asynchronous motor: IRFOC and DTC

MPPT Optimal Torque Control Strategy for a PMSG-based Wind Turbine Emulator

A wind turbine emulator is a valuable tool, which enables real-time physical simulation of a wind turbine behavior using a dedicated experimental test setup, providing a controlled environment for research and development purposes. One significant advantage of using this tool is its ability to test control algorithms designed to maximize power extraction from the wind turbine. This paper continues previous work on developing a small-scale variable-speed wind turbine emulator based on a Permanent Magnet Synchronous Generator for stand-alone applications (Benhacine et al., 2024). This paper presents enhancements made to the emulator. These improvements facilitate the assessment of a maximum power point tracking control strategy designed to optimize power extraction from the wind turbine.

Wind turbine emulator using three-phase IM controlled through an adaptive reactive power estimator fed by soft-VSI topology

PurposeThe purpose of this paper aims to design a robust wind turbine emulator (WTE) based on a three-phase induction motor (3PIM).Design/methodology/approachThe 3PIM is driven by a soft voltage source inverter (VSI) controlled by a specific space vector modulation. By adjusting the appropriate vector sequence selection, the desired VSI output voltage allows a real wind turbine speed emulation in the laboratory, taking into account the wind profile, static and dynamic behaviors and parametric variations for theoretical and then experimental analysis. A Mexican hat profile and a sinusoidal profile are therefore used as the wind speed system input to highlight the electrical, mechanical and electromagnetic system response.FindingsThe simulation results, based on relative error data, show that the proposed reactive power control method effectively estimates the flux and the rotor time constant, thus ensuring an accurate trajectory tracking of the wind speed for the wind emulation application.Originality/valueThe proposed architecture achieves its results through the use of mathematical theory and WTE topology combine with an online adaptive estimator and Lyapunov stability adaptation control methods. These approaches are particularly relevant for low-cost or low-power alternative current (AC) motor drives in the field of renewable energy emulation. It has the advantage of eliminating the need for expensive and unreliable position transducers, thereby increasing the emulator drive life. A comparative analysis was also carried out to highlight the online adaptive estimator fast response time and accuracy.

Test rig for stand-alone small power wind turbine emulation for variable wind and load

This paper presents futures from experimental investigation of an autonomous small power wind system. The envisaged wind system is based on a PMSG (Permanent Magnet Synchronous Generator) directly connected to the wind turbine shaft, while the DC output load is supplied by a rectifier and a chopper. The DC load is considered as a resistive load with wide values range. Experimental investigations are provided in partial load regime. The power optimization is performed through a power loop in two ways: by controlling the electrical power or by controlling the electromechanical power. For the above two situations it is shown how the optimization power loop reference and power loop feedbacks can be set, in order to obtain maximum electrical power, for each wind speed value corresponding to the partial load regime. It was also highlighted that for a wide range of DC load values the mechanical and electrical powers are not constant as it should be corresponding to the mathematical model of the optimal conversion. This is due to mechanic-electrical subsystem processes. The electrical power variation range with the load should be provided by the manufacturer in the low-power wind system data sheet.

Design, implementation, and experimental validation of a new low-cost sensorless wind turbine emulator: Applications for small-scale turbines

Research and investigation into renewable energy sources is being sparked by the rapidly rising need for electricity, higher costs of fossil fuels, and increasing worries about the environment. Recent years have seen a tremendous increase in the use of wind energy (WE). In-depth study has been done to effectively produce power from WE. Nevertheless, it is exceedingly challenging and dangerous to set up wind turbines (WTs) for research and teaching uses due to constraints like space and upkeep. Numerous benefits come with a lab-scale WT emulator (WTE), such as freedom from space restrictions, an improved level of control, and independence from existing weather conditions. The design and execution of a low-power, lab-scale WTE are the focus of this study. The investigated experimental configuration is intended to precisely mimic the mechanical behavior of a real WT. Aerodynamics, blades, slow shafts, gearboxes, and controller elements, for example, are modeled in MATLAB/Simulink before they are assembled and implemented on a dSPACE 1104 board. A DC motor running under buck converter control is used to substitute the quick shaft. The WTE’s functionality is evaluated in various wind speed conditions. The findings of comparing the WTE’s dynamics with those offered by the manufacturer amply show the efficacy of the proposed WTE and its capacity to take the position of an actual WT. This paper will be a useful resource for investigators in helping them select the best WTE approach for their purposes.

A complete ultra-large wind turbine emulator for wind harvest evaluation: design and implementation

A complete ultra-large wind turbine emulator for wind harvest evaluation: design and implementation

Modelling of Variable Speed Wind Turbine Connected DFIG:250KW

This manuscript initiates the design and analysis of a doubly-fed-induction-generator (DFIG) linked to the grid, aiming to assess a wind vitality conversion configuration employing an emulated wind turbine drive system. The generator’s configuration involves integrating the d-q axes reference framework with the stator flux. Independent management of real, and imaginary power, along with the dc-bus potential at the grid, is achieved through the field-aligned regulating method. Controlling real, and Quadrature power, as well as DC-bus potential, is executed using tandem converters at distinct velocities, encompassing sub, syn, and hyper-synchronous speeds. The effectiveness of these control strategies is validated through the emulation of a variable-speed wind turbine-connected DFIG, showcasing precise control over DC voltage, reactive power, and active power.

Laboratory-Scale Airborne Wind Energy Conversion Emulator Using OPAL-RT Real-Time Simulator

Airborne wind energy systems (AWES) are more efficient than traditional wind turbines because they can capture higher wind speeds at higher altitudes using connected kite generators. Securing a real wind turbine or a site with favorable wind conditions is not always an assured opportunity for conducting research. Hence, the Research and Development of the Laboratory Scale Airborne Wind Energy Conversion System (LAWECS) require a better understanding of airborne wind turbine dynamics and emulation. Therefore, an airborne wind turbine emulation system was designed, implemented, simulated, and experimentally tested with ground data for the real time simulation. The speed and torque of a permanent magnet synchronous motor (PMSM) connected to a kite are regulated to maximize wind energy harvesting. A field-oriented control technique is then used to control the PMSM’s torque, while a three-phase power inverter is utilized to drive the PMSM with PI controllers in a closed loop. The proposed framework was tested, and the emulated airborne wind energy conversion system results were proven experimentally for different wind speeds and generator loads. Further, the LAWECS emulator simulated a 2 kW, 20 kW, and 60 kW designed with a projected kite area of 5, 25, and 70 square meters, respectively. This system was simulated using the Matlab/Simulink software and tested with the experimental data. Furthermore, the evaluation of the proposed framework is validated using a real-time hardware-in-the-loop environment, which uses the FPGA-based OPAL-RT Simulator.

Robust Control for Torque Minimization in Wind Hybrid Generators: An H∞ Approach

This study focuses on implementing a wind turbine emulator based on a permanent magnet synchronous machine with excitation auxiliary windings and thoroughly investigates the space harmonics created by this innovative topology in MATLAB/Simulink. A Hybrid Generator (HG) is a robust generator that does not have slip rings or brushes in its structure. Furthermore, the flux of the hybrid generator HG may be easily adjusted as it is created by direct current excitation coils and permanent magnets. Unfortunately, the space harmonic rate in the HG is relatively high. In other words, the mechanical vibrations caused by the electromagnetic torque ripple threaten the drive train’s behaviour and, ultimately, the wind turbine’s lifespan. This study describes two methods for decreasing the ripple in electromagnetic torque. Both circuit architecture and robust H∞ control techniques are considered. After simulating the two approaches, a list of requirements is provided for the maximum allowable amplitude of the inductance and the flux harmonics.

Inertia compensation for wind turbine emulator based on anticipation deviation suppression

The wind turbine emulator (WTE) is an important tool for dynamic emulation experiments of wind turbines. This paper studies the problem of high-frequency fluctuation of the rotating speed of the dynamic emulation platform when emulating the mechanical dynamics of large inertia wind turbine under fluctuating wind speed. Through the time domain analysis of the discrete mathematical model of the WTE, it is found that the torque compensation loop of the transmission system will incur the acceleration deviation because of the influence of the time delay, and this anticipatory deviation increases with the increase of the compensation multiple. As a result, the acceleration of the transmission chain oscillates, resulting in high-frequency fluctuations in the rotational speed. To this end, this paper proposes an inertia compensation scheme for the WTE based on the anticipation deviation suppression. Based on the principle of zero-pole configuration, a feedforward suppressor is designed to offset the zero-pole of the closed-loop transfer function of the transmission chain system, in order to eliminate the high-frequency fluctuation of the rotating speed caused by the torque deviation. The effectiveness of the proposed strategy is validated using the maximum power point tracking control experiment.

Accurate wind energy harvest assessment using a comprehensive ultra-large-wind-turbine emulation

A comprehensive 5 MW wind turbine emulator's design and implementation are designed and investigated thoroughly in this paper. A separately excited DC motor set under the control of a current-controlled drive forms the basis of the suggested emulation. The emulation algorithms that simulate the features of the 5 MW wind turbine are run on a digital signal processor (DSP). These algorithms regulate the DC motor's current, which in turn regulates the torque. The results obtained demonstrate that the system was successful in accurately simulating the transient and steady-state characteristics of the 5 MW wind turbine. The emulator system was initially tested and validated with simulation results using MATLAB/Simulink code attached to both the FAST and TurbSim models. Furthermore, step and stochastic wind profiles were used to experimentally verify and test it. Nearly all of the power that is available in the wind turbine system is successfully obtained using the maximum power point tracking technique, which is used to find the best operating point. The created wind turbine emulator can be used to precisely assess energy harvesting by examining various mechanical and electrical properties of the Permanent Magnet Synchronous Generator (PMSG) vastly used in ultra-large wind turbine nacelles.

Implementation and analysis of mono inverter-battery configuration for wind driven doubly fed induction generator

ABSTRACT This paper investigates the controller implementation and analysis of Doubly Fed Induction Generator (DFIG) for powering isolated loads in rural electrification. A simple speed sensorless algorithm-assisted controller for isolated power supply of DFIG has been proposed using a digital controller and voltage source converter at the rotor terminals of the generator. The controller can automatically correct the voltage and frequency of the rotor side inverter pulse to obtain a desired voltage and frequency at stator side despite the variations in the wind speed and load. A hardware prototype of the system has been built and tested on a prototype machine, which is driven by an emulated wind turbine under sub-synchronous and super-synchronous speed operations. The detailed results of both simulated and hardware waveforms are provided in the paper to demonstrate the working of the proposed topology and embedded control scheme. Further, the performance characteristics of DFIG are modeled and verified experimentally. A good agreement exists between theoretical and experimental results.

Optimized Wind Turbine Emulator based on an AC to DC Motor Generator Set

This study presents an Optimized Wind Turbine Emulator (OWTE) based on a DC generator driven by a three-phase Induction Motor (IM). The IM speed is varied using an AC drive that converts fixed RMS voltage and frequency to variable ones due to v/f control. The frequency reference of the control was calculated through optimized equations of a wind turbine model for maximum power and torque. The overall system was simulated on Matlab/Simulink using a wind speed profile scenario. An experimental test bench controlled by a TMS320F28379D card was set up in the laboratory to confirm the effectiveness of the obtained simulation results.

Wind SRG-Based Bipolar DC Microgrid with Grid-Connected and Plug-In Energy Supporting Functions

Although a switched reluctance generator (SRG) is not the mainstream wind generator, it possesses the application potential and is worth developing for its many structural merits and high developed power ability. This paper presents a wind SRG-based bipolar DC microgrid having grid-connected and plug-in energy supporting functions. First, a surface-mounted permanent magnet synchronous motor (SPMSM)-driven wind turbine emulator (WTE) is established. Next, the wind SRG with an asymmetric bridge converter is developed. Good generating characteristics are obtained through proper designs of power circuit, commutation mechanism, external excitation source, voltage and current controllers. Third, a DC/DC boost interface converter and a bipolar voltage balancer are constructed to establish the 500 V microgrid bipolar DC-bus. To preserve the microgrid power supplying quality, a battery energy storage system (BESS) with bidirectional DC/DC interface converter is equipped. A dump load leg is added across the bus to limit the DC-bus voltage under energy surplus condition. In load side, a three-phase bidirectional load inverter is developed, which can be operated as a single-phase three-wire (1P3W) inverter or a three-phase three-wire (3P3W) inverter. Good sinusoidal voltage waveform and regulation characteristics are obtained using the proportional-resonant (PR) control. The microgrid to load and microgrid to grid operations are conductible. Finally, to further improve the powering reliability of microgrid, a three-phase T-type Vienna switch-mode rectifier (SMR) based plug-in energy supporting scheme is developed. When the microgrid energy shortage occurs, the possible harvested energy can be used to supply the microgrid.

Wind Turbine Emulators—A Review

Renewable energy sources have become a significant alternative energy source due to the continuing depletion of conventional energy sources and fluctuation in fuel costs. Currently, wind energy is the foremost among all other renewable energy sources. However, modeling and analyzing industrial wind turbines is complex as the wind turbine power ratio and size have steadily increased. Undoubtedly, industrial wind turbines are huge and challenging to keep in research labs; simultaneously, exploring the controller/power converter performance is practically impossible. Therefore, to overcome the above drawbacks, wind turbine emulators have been developed to achieve the static and dynamic characteristics of wind energy conversion systems. This paper aims to present a comprehensive review of the different wind turbine emulators available in the literature. In addition, the implementation of real-time emulators is classified according to the structure and approaches. Furthermore, an extensive analysis of the emulators was presented based on the significant parameters utilized for the real-time wind turbine emulators. Finally, this review analyzes the different emulator topologies according to cost, accuracy, complexity, and hardware implementation.

Wind turbine emulator control improvement using nonlinear PI controller for wind energy conversion system: Design and real‐time implementation

SummaryWind turbine emulators (WTE) have become a necessity for testing, developing, and improving design and control strategies in the renewable energy domain. The aim of this paper is to realize an experimental standalone wind energy conversion system emulator (WECSE) with improved torque and current control strategy using a nonlinear PI controller. The prototype was developed with a separately excited DC motor to simulate the wind turbine by providing the required speed and torque for power generation using a directly driven wound‐rotor synchronous generator and a power conversion system controlled by a modified drift‐free Perturb and Observe (P&O) Maximum Power Point Tracking algorithm (MPPT). The DC motor torque is controlled by an nonlinear PI controller regulator for an estimated current reference through a chopper driven by a dSPACE control board where the MATLAB/Simulink platform is used for wind turbine simulation. The proposed method was validated by experimental tests for different wind speeds and was compared with the conventional method. The experimental results have demonstrated that the control, emulation, and MPPT performances of the proposed method are significantly better.

Integration of Wind and PV Systems Using Genetic-Assisted Artificial Neural Network

The prominence of Renewable Energy Sources (RES) in the process of power generation is exponentially increased in the recent days since these sources assist in minimizing the environmental contamination. A grid-tied DFIG (Doubly Fed Induction Generator) based WECS (Wind Energy Conversion System) is introduced in this work, in which a Landsman converter is implemented to improvise the output voltage of PV without any fluctuations. A novel GA (Genetic Algorithm) assisted ANN (Artificial Neural Network) is employed for tracking the Maximum power from PV. Among the rotor and grid side controllers, the former is implemented by combining the stator flux with d-q reference frame and the latter is realized by the PI controller. The proposed approach delivers better performance in the compensation of real and reactive power along with the DC link voltage control. The controlling mechanism is verified in both MATLAB and experimental bench setupby using an emulated wind turbine for the concurrent control of DC link potential, active and reactive powers.The source current THD is observed as 1.93% and 2.4% for simulation and hardware implementation respectively.

On-line assessment of wind turbine emulator with pitch control mechanism

On-line assessment of wind turbine emulator with pitch control mechanism

Sliding Mode Control for Wind Turbine Emulator based on Advanced Space Vector Modulation Technique for Two-Phase Induction Motor Drive

This paper proposes an improved Wind Turbine Emulator (WTE) structure using Sliding Mode Control (SMC) technique based on the Two-Phase Induction Motor (TPIM) for software simulation laboratory purposes. Since the power electronic converters application with various control strategies in the AC machine drive field facilitates the wind turbine characteristics imitation, an advanced SVM controlled-2ϕ-inverter is adopted. Considering the asymmetry between the TPIM main and auxiliary windings, mathematical equations were studied allowing control of the speed and the torque under different conditions. The 2-phase-inverter is controlled through an appropriate adjustment of four space voltage vectors. In order to enhance the speed and flux regulation loops and to increase the system robustness against the motor parameters variation and the wind sudden fluctuations, the SMC theory, which contains the adaptive rotor flux observer is used here to develop a control law that governs the system to track the reference speed set by the WT mathematical model to obtain the desired output. Several parameters, such as electromagnetic torque, rotor fluxes, stator currents, and rotor speed, were analyzed. Static and dynamic characteristics and the WTE transient and steady-state responses are satisfactorily reproduced by the proposed emulator scheme.