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Wind power has rapidly emerged as a leading renewable energy source, with doubly-fed induction generators gaining attention for their independent power control capability. Integrating doubly-fed induction generator-based wind farms into the grid requires significant upgrades to transmission and distribution infrastructure to fully harness wind energy's potential and address challenges like sub-synchronous control interaction. This phenomenon poses risks such as equipment damage and power supply interruptions. To mitigate these risks, a novel adaptive control strategy incorporating uncertainty and disturbance estimators, alongside H∞ and μ-synthesis controllers, is proposed. By introducing a time delay into the control system, oscillations can be detected and stabilized, ensuring system stability across various operational conditions. The controller parameters are optimized using a dynamic opposite learning-based enhanced mountain gazelle optimization algorithm. This algorithm is utilized to determine the optimal controller parameters that ensure system stability across different operational conditions. Simulation results conducted in MATLAB validate the effectiveness of the proposed controller in damping oscillations under different compensations and wind speeds. Specifically, it demonstrates superior damping capabilities at various wind speeds and compensations, enhancing power system stability and reliability. Results confirm the better damping capability of proposed controller under different compensations such as 75% and 45% and wind speeds such as 13 m/s, 7 m/s, and 11 m/s. This research provides better stability and reliability of power systems by dampening oscillations at 1.5 s, ensuring the sustainable integration of wind energy. [ABSTRACT FROM AUTHOR]

This study aims to ameliorate the contribution capability of doubly-fed induction generator (DFIG) to participate in standalone microgrid operation. The islanded microgrid consists of a solar photovoltaic array for solar energy conversion and battery energy storage in addition to DFIG-based wind energy conversion system. Using a simplified control approach, the study describes multi-mode operation of a DFIG-based AC/DC microgrid using a stator-side solid-state transition switch (SSTS). Using SSTS operation, the DFIG stator can be seamlessly disconnected and reconnected from the point of common coupling without interrupting power to the loads in the microgrid. Additionally, non-ideal AC loads can be handled efficiently without the need for computationally exhaustive approaches to enhance stator voltages and currents. [ABSTRACT FROM AUTHOR]

Summary: According to recent research work, increasing electric power generation is one of the significant advantages of the dual‐rotor wind turbine (DRWT) compared to the other types for the same wind speed. In this research work, a modified super‐twisting sliding mode control (STSMC) based on the neural network (NN) is suggested to regulate the stator powers of a DRWT‐based doubly‐fed induction generator (DFIG) in normal and unbalanced grid fault modes. The design of this strategy involves replacing the gains of conventional STSMC with the NN algorithm to enhance robustness, mitigate the impact of unbalanced grid voltage, and consequently improve the quality of the generated power of DRWT‐based DFIG. This forms the primary contribution of this work. The suggested strategy is compared with vector control (VC) and conventional STSMC in terms of reference tracking, power ripples, response dynamics, harmonic distortion of stator current, and the effect of an unbalanced grid fault. Finally, the utility and effectiveness of the designed controller are confirmed through computer simulations. Furthermore, when the grid is subjected to a 20% voltage drop, the results demonstrate that the suggested strategy reduced the total harmonic distortion (THD) value of the stator current by 12.92% compared to VC and by 9.29% compared to conventional STSMC. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Power quality is a crucial determinant for integrating wind energy into the electrical grid. This integration necessitates compliance with certain standards and levels. This study presents cascadedfuzzy power control (CFPC) for a variable-speed multi-rotor wind turbine (MRWT) system. Fuzzy logic is a type of smart control system already recognized for its robustness, making it highly suited and reliable for generating electrical energy from the wind. Therefore, the CFPC technique is proposed in this work to control the doubly-fed induction generator (DFIG)-based MRWT system. This proposed strategy is applied to the rotor side converter of a DFIG to improve the current/power quality. The proposed control has the advantage of being model-independent, as it relies on empirical knowledge rather than the specific characteristics of the DFIG or turbine. Moreover, the proposed control system is characterized by its simplicity, high performance, robustness, and ease of application. The implementation of CFPC management for 1.5 MW DFIG-MRWT was carried out in MATLAB environment considering a variable wind speed. The obtained results were compared with the direct power control (DPC) technique based on proportional-integral (PI) controllers (DPC-PI), highlighting that the CFPC technique reduced total harmonic distortion by high ratios in the three tests performed (25%, 30.18%, and 47.22%). The proposed CFPC technique reduced the response time of reactive power in all tests by ratios estimated at 83.76%, 65.02%, and 91.42% compared to the DPC-PI strategy. Also, the active power ripples were reduced by satisfactory proportions (37.50%, 32.20%, and 38.46%) compared to the DPC-PI strategy. The steady-state error value of reactive power in the tests was low when using the CFPC technique by 86.60%, 57.33%, and 72.26%, which indicates the effectiveness and efficiency of the proposed CFPC technique in improving the characteristics of the system. Thus this control can be relied upon in the future.

The direct power command (DPC) of the doubly-fed induction generators (DFIG) has garnered increasing attention due to its simplicity, ease of implementation, and fast dynamic response that distinguished it from other controls. Recently, nonlinear controllers have been suggested to improve the DPC robustness, in particular the minimization of the DFIG power fluctuations. In the present research work, two different controls are used to regulate the DFIG power, where the first is a traditional DPC and the second is the DPC based on neural super-twisting algorithm (NSTA) controllers. The NSTA controllers were used instead of hysteresis comparators in the DPC technique, and the pulse width modulation (PWM) technique was used as a suitable solution instead of the switching table to better manage the state of switches and simplify the control system. The proposed controls were investigated and implemented using Matlab software and Dspace 1104 card with different tests to determine the best control. Experimental and simulation results show the good efficiency of the NSTA controller in improving energy and current quality. Also, the comparison is made between both techniques and the other controls in terms of reducing current harmonic distortions and ratios of the DFIG power fluctuations. [ABSTRACT FROM AUTHOR]

This paper presents a novel hybrid type-2 fuzzy sliding mode control approach for regulating active and reactive power exchanged with the utility grid by a doubly-fed induction generator in a wind energy conversion system. The main objective of this hybridization is to eliminate the steady-state chattering phenomenon inherent in sliding mode control while improving the transient delays caused by type-2 fuzzy controllers. In addition, the proposed control approach has proven to be successful in coping with varying generator parameters and exhibited good reference tracking. An in-depth comparative study with state-of-the-art advanced control techniques is also the focus of the present paper. The comparative study has three objectives, namely: a qualitative comparative study that aims to compare response times and reference tracking capabilities; a quantitative evaluation that takes into account time-integrated performance criteria; and finally, robustness capabilities. The simulation results, carried out in the Matlab/Simulink environment, have demonstrated the effectiveness and best performance of the proposed hybrid type-2 fuzzy sliding mode control with respect to other advanced techniques included in the comparison study. [ABSTRACT FROM AUTHOR]

This paper consecrates to a comparative performance study of singly-fed and doubly-fed of induction generators thrusted by wind power turbine of similar generation capacity of 2.5 kW, and constant or variably wind speed. The singly-fed induction generator model could be represented using natural reference frame and doubly-fed induction generator model is described using a Park reference frame. Because of several physical domains existing in both induction generators like mechanical and electrical, modeling of generators is difficult, therefore the modeling based on physical methods takes a high credibility under these conditions. Among the procedures is Bond-graph method that models the systems based on law of mass conservation and/or law of energy conservation containing in the systems. Modeling the parts of both singly-fed and double-fed induction generators are based on Bondgraph method. We found that the impact of stator coil winding for on the current is in the form of changes of its value and steady state intervals; increasing the number of stator coil windings may also lead to increased stator current and the longer their steady state interval. Our study demonstrates also that doubly-fed induction generator possesses advantages compared to singly-fed induction generator, namely better current quality output and an adaptation to fluctuating wind speeds. The performance study is done in constant and variably wind speeds using simulated results of 20-Sim software. [ABSTRACT FROM AUTHOR]

Power quality is a crucial determinant for integrating wind energy into the electrical grid. This integration necessitates compliance with certain standards and levels. This study presents cascadedfuzzy power control (CFPC) for a variable-speed multi-rotor wind turbine (MRWT) system. Fuzzy logic is a type of smart control system already recognized for its robustness, making it highly suited and reliable for generating electrical energy from the wind. Therefore, the CFPC technique is proposed in this work to control the doubly-fed induction generator (DFIG)-based MRWT system. This proposed strategy is applied to the rotor side converter of a DFIG to improve the current/power quality. The proposed control has the advantage of being model-independent, as it relies on empirical knowledge rather than the specific characteristics of the DFIG or turbine. Moreover, the proposed control system is characterized by its simplicity, high performance, robustness, and ease of application. The implementation of CFPC management for 1.5 MW DFIG-MRWT was carried out in MATLAB environment considering a variable wind speed. The obtained results were compared with the direct power control (DPC) technique based on proportional-integral (PI) controllers (DPC-PI), highlighting that the CFPC technique reduced total harmonic distortion by high ratios in the three tests performed (25%, 30.18%, and 47.22%). The proposed CFPC technique reduced the response time of reactive power in all tests by ratios estimated at 83.76%, 65.02%, and 91.42% compared to the DPC-PI strategy. Also, the active power ripples were reduced by satisfactory proportions (37.50%, 32.20%, and 38.46%) compared to the DPC-PI strategy. The steady-state error value of reactive power in the tests was low when using the CFPC technique by 86.60%, 57.33%, and 72.26%, which indicates the effectiveness and efficiency of the proposed CFPC technique in improving the characteristics of the system. Thus this control can be relied upon in the future. [ABSTRACT FROM AUTHOR]

The development of fault detection methods in wind turbine (WT), especially for single fault detection, is continuously increasing. However, the rapid growth of fault detection in WT leads to another challenge where multiple faults can occur. The single fault detection method in WT is no longer reliable, especially when multiple faults occur simultaneously. Therefore, multiple faults detection in doubly-fed induction generators (DFIG) WT was proposed using an artificial neural networks (ANN) model. These multiple faults include internal and external stator faults happening simultaneously. Internal stator faults cover inter-turn short circuit faults and open circuit faults, while external stator faults cover loss of excitation and external short circuit faults. The performance of the developed multiple faults detection model was measured using accuracy and the root mean square error (RMSE) value. The results show that the developed model performs well with high accuracy and a low RMSE value. Thus, the developed model can accurately detect the coexistence of multiple faults in DFIG WT. [ABSTRACT FROM AUTHOR]

In this work, a new indirect field-oriented command (IFOC) for wind systems based on a doubly-fed induction generator (DFIG) is designed to get better energy and stream quality. Also, overcoming the problems of IFOC. It is proposed to use proportional dual integral (PDI) controllers in order to replace traditional controllers and augment the robustness of the studied wind turbine system. The proposed IFOC-PDI is a modification of the IFOC, where the basic idea behind the designed technique is to combine a proportional-integral (PI) regulator with an integral term. This technique has been applied to the machine inverter, where the IFOC-PDI aims to calculate reference voltage values. The pulse width modulation (PWM) is used to translate voltage reference values ​​into pulses to run the machine inverter. The main objective of this article is to compare the competence of the IFOC-PDI to that of the IFOC-PI in different tests, including two different wind speed profiles and DFIG parameters variation. The major benefit of this command is a decrease in harmonic distortion of the currents, and active and reactive power (Ps and Qs) fluctuations. The results using MATLAB demonstrated that the IFOC-PDI improved the IFOC-PI in the minimization of stream harmonic distortion (6.63%, 10.42%, and 17.86%) and notable minimization of fluctuations in both Ps (32.08%, 46.24%, and 12.10%) and Qs (45.95%, 66.88%, and 14.49%). Also, the overshoot value of Ps was minimized compared to the IFOC-PI in all tests by ratios estimated at 57.79%, 12.41%, and 33.96%. The steady-state error of Ps was minimized compared to the IFOC-PI in all tests by ratios estimated at 29.43%, 85.88%, and 76.36%. The IFOC-PDI is also very resistant in the case of DFIG parameters variation.

Abstract The paper proposes a nonlinear controller called dual super-twisting sliding mode command (DSTSMC) for controlling and regulating the rotor side converter (RSC) of multi-rotor wind power systems that use doubly-fed induction generators. It was proposed that this controller be developed as an alternative to the direct power control (DPC), which makes use of a pulse width modulation (PWM) strategy to regulate the RSC's functioning. Overcoming the power/current quality issue with the proposed technique (DPC-DSTSMC-PWM) is characterized by great robustness and excellent performance. The designed strategy was contrasted with the standard method of control and other methods already in use. So, the unique proposed control strategy’s robustness, performance, efficiency, and efficacy in enhancing system characteristics were tested and validated in Matlab/Simulink. In both tests, the proposed method resulted in significant improvements, reducing active power ripples by 83.33%, 57.14%, and 48.57% in the proposed tests. When compared with the traditional regulation method, the reduction rates of reactive power ripples are 64.06%, 52.47%, and 68.7% in the tests. However, in contrast to the conventional method, the proposed tests showed a decrease of between 72.46%, 50%, and 76.22% in the value of total harmonic distortion (THD) of the provided currents. These ratios show how effective the proposed plan is in ameliorating and enhancing aspects of the energy system.

The paper proposes a nonlinear controller called dual super-twisting sliding mode command (DSTSMC) for controlling and regulating the rotor side converter (RSC) of multi-rotor wind power systems that use doubly-fed induction generators. It was proposed that this controller be developed as an alternative to the direct power control (DPC), which makes use of a pulse width modulation (PWM) strategy to regulate the RSC's functioning. Overcoming the power/current quality issue with the proposed technique (DPC-DSTSMC-PWM) is characterized by great robustness and excellent performance. The designed strategy was contrasted with the standard method of control and other methods already in use. So, the unique proposed control strategy's robustness, performance, efficiency, and efficacy in enhancing system characteristics were tested and validated in Matlab/Simulink. In both tests, the proposed method resulted in significant improvements, reducing active power ripples by 83.33%, 57.14%, and 48.57% in the proposed tests. When compared with the traditional regulation method, the reduction rates of reactive power ripples are 64.06%, 52.47%, and 68.7% in the tests. However, in contrast to the conventional method, the proposed tests showed a decrease of between 72.46%, 50%, and 76.22% in the value of total harmonic distortion (THD) of the provided currents. These ratios show how effective the proposed plan is in ameliorating and enhancing aspects of the energy system. [ABSTRACT FROM AUTHOR]

Energy ripples are among the common problems in renewable energies as a result of using less efficient strategies. In this work, a new technique is suggested to control a doubly-fed induction generator (DFIG) using the pulse width modulation (PWM). The new technique is based on the combination of neural networks and fractional-order control to minimize the reactive and active power ripples of the DFIG-based variable speed dual-rotor wind turbine system. The suggested fractional-order neural control (FONC) with the PWM is a simple, robust and a high-performance strategy. Simulation is performed using Matlab software to validate the effectiveness of the designed control of 1.5 MW DFIG and the obtained results are compared with the traditional direct power control (DPC) in different working conditions. In addition, the comparison between the suggested control and the DPC is performed in the cases of changing or not changing the device parameters in terms of ripple ratio, dynamic response, steady-state error, current quality, and overshoot of active and reactive power of the DFIG. As compared to the DPC, the proposed FONC technique improves the active and reactive power ripples by 65.71% and 84.74%, respectively. Also, improves the overshoot of the active and reactive power by 71.33% and 91.72%, respectively. The simulation results demonstrate the high performance and robustness of the FONC technique for the parametric variations of the DFIG-based variable speed dual-rotor wind turbine system compared to the DPC control. [ABSTRACT FROM AUTHOR]

Conventional protection schemes for wind farm-flexible flexible direct current (DC) system transmission lines are susceptible to malfunctions in external fault scenarios and exhibit limited immunity to fault resistance in internal fault scenarios. In the pursuit of enhancing pilot protection performance, a novel protection method based on high-frequency inductance difference coefficients is proposed. Firstly, the fault transient characteristics of both the wind farm and the flexible DC converter are analyzed, deriving their respective transient models. Subsequently, a high-frequency fault component network comprising inductive impedances is constructed. Then, a protection criterion based on high-frequency inductance difference coefficients is formulated. Finally, the proposed method is subjected to simulation tests on the RT-LAB platform. The results validate its capability to accurately identify the locations of internal and external faults, demonstrating robust immunity to fault resistance. Because it operates independently of synchronous information interaction, it functions rapidly.

The rapid increase of wind power penetration has threatened the frequency stability of regional power grids, and the loss of system inertia is viewed as the key issue to be solved. Catering to this problem, this paper proposes a rotational reference frame (RRF) control method for the doubly-fed induction generator based wind turbines (DFIG-WTs) to improve the inertia frequency response. An anti-frequency-deviation phase delay is introduced into the phase angle measured by the phase-locked loop (PLL). The dq-RRF of the control system of a DFIG-WT is rotated such that the voltage vectors of the stator and the grid-side converter (GSC) moved like the internal voltage vector of a synchronous generator. Frequency domain analysis is carried out to evaluate the stability of the system and the robustness to the variations of control parameters of the DFIG-WT. Both simulation studies and hardware-in-the-loop experiment are carried out for frequency and active power response. Results show that the RRF controller not only inherits stronger robustness and simpler structure, but also is able to provide stronger inertial support against the drop of system frequency than the widely used synthetic inertia control (SIC) method.

For power grids with a high penetration level of wind power generation, stochastic wind speed variation adversely affects the frequency stability. A variable-speed wind turbine generator would deloads its output by shifting the power operating point to provide frequency response. Because the wind speed variation directly affects the calculation of the operating point, difficulties arise in securing a reliable amount of the frequency response. This paper proposes a control scheme of a doubly fed induction generator (DFIG)-based wind generation providing the primary frequency reserve (PFR), which can improve its reliability and flexibility even with a continuously varying wind speed. To achieve these objectives, the proposed scheme employs a de-loaded operation control loop associated with the rotational inertia characteristics of the DFIG. In addition, a static gain-based droop control loop is employed to release the required amount of active power from the system operator. In the proposed scheme, the optimal operating point for de-loaded operation varies more smoothly than it does in a conventional scheme by using the rotor inertia characteristics. The performance of the proposed control scheme is demonstrated using an EMTP-RV simulator under various wind speeds. The simulation results indicate that the proposed scheme significantly improves the frequency support capability of the DFIG in both the process of securing and providing the PFR.

Experimental work using Hardware-in-the-loop simulation is performed in this article for a power system based on multi-rotor wind energy for power generation. Power is generated using a doubly-fed induction generator (DFIG), where the suggested approach to regulate the energy is different from the direct power command (DPC) in terms of idea and structure, even though the same equations are used to estimate the powers. Two parallel super-twisting controls are used to control the power, and modified space vector modulation (MSVM) is used to operate the rotor side converter. The designed command is unrelated to the system’s mathematical model and uses only a few gains, which makes it an effective and distinctive effectiveness compared to the DPC based on the super-twisting controller (DPC-STC). Also, simplicity, robustness, and ease of application are the most notable characteristics of the suggested command. Moreover, an uncontrolled grid-side converter was used to demonstrate the efficacy and competence of the suggested command in ameliorating the features of the designed power system. The suggested command was first verified in MATLAB, and the results were confirmed using experimental work, where Hardware-in-the-loop using the dSPACE 1104 was used for this purpose. In this work, the results obtained with the DPC-STC technique were compared in terms of undulations and oscillation minimization ratio, total harmonic distortion (THD) of stream, and steady-state error (SSE) value. The designed command minimized the THD of current with an efficiency of 45.94%, 46.95%, and 45.93% in the first test, second test, and third test, respectively. Also, the active power undulations were minimized compared to the DPC-STC by58.33%, 45.60%, and 44.88% in the first test, second test, and third test, respectively. The SSE of reactive power was also reduced by 68%, 71.32%, and 70.80% in the first test, second test, and third test, respectively. These ratios indicate the effectiveness, ability, and efficiency of the suggested command to ameliorate the efficiency of the power system.

This new paper describes an experimental investigation of a proportional-integral (PI) controller that uses feedback control to regulate an energy system that uses multi-rotor wind energy systems. Pulse width modulation (PWM) is used by the proposed controller to control the power of the doubly-fed induction generator controlled by direct power control (DPC), which is intended to regulate and control the inverter. The proposed strategy differs from the traditional DPC strategy. The proposed control was studied in the case of variable wind speed, where the MATLAB and Dspace 1104 environment was used to implement this proposed feedback PI (FPI) controller, with a comparison with the proposed control technique and some existing works. The suggested FPI controller outperforms the traditional controller and certain other controllers in terms of lowering energy ripples, overshoot, steady-state error (SSE), response time, and the total harmonic distortion (THD) of supplied system currents, as demonstrated by experimental and simulation results. The THD value of current was reduced by 64.86% and 69.44% in the two proposed tests compared to the traditional DPC technique. Also, the value of ripples and overshoot of active power was reduced compared to the DPC method by 95.42% and 90.86%, respectively, in the case of step wind speeds. Moreover, ripples and SSE of reactive powers compared to the DPC technique were reduced by 37.51% and 84.13%, respectively. These high ratios indicate the high performance of the proposed DPC-FPI technique in enhancing the features of the system in contrast to the conventional DPC technique.

In this paper, we present a novel design and development of wind energy conversion systems (WECS) for a doubly-fed induction generator (DFIG). A hysteresis current control is used to improve the DC bus for rectifier and smart current control by model predictive of three-level-NPC (3L-NPC) inverter. The advantages of this intelligent method are such as fast dynamic answers and the easy implementation of nonlinearities, and that it requires fewer calculations to choose the best switching state. In addition, an innovative algorithm is proposed to adjust the current ripples and output voltage harmonics of the wind energy conversion system. The performance of the system was analysed by simulation using MATLAB/Simulink.

This paper proposes a new integral-synergetic controller for direct reactive and active powers control (DARPC) for a grid-connected doubly-fed induction generators (DFIGs) in dual-rotor wind power generation applications. The proposed DARPC strategy employs integral-synergetic control (ISC) to regulate the reactive and active powers of the DFIG-based variable speed dual-rotor wind turbine systems. The proposed ISC technique is the contribution of this work, where this strategy is a development of synergetic control and simplicity and robustness are the most prominent features. The main advantages of the proposed ISC-DARPC technique are ease of implement, good dynamic response, simple structure, and constant switching frequency operation. The Matlab software is used to validate the design of the ISC-DARPC technique, and the obtained results are compared with traditional DARPC. In addition, the ISC-DARPC technique is able to fully minimize ripples in both torque and active power during grid voltage imbalance or parametric changes on the DFIG. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to address the issue of control of a variable-speed wind turbine based on doubly-fed induction generators. In this work, an effort is made to extract the maximum efficiency from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. In the first step, a maximum power point tracking technique is used to extract the maximum power from the turbine. Then a stator-flux-oriented vector control strategy is employed to control the rotor-side current. Subsequently, a grid voltage vector-oriented control strategy is used to control the grid-side system of the grid-connected generator. Considering the nonlinearity and parameter uncertainty of the system, an active disturbance rejection controller with a sliding-mode-based extended-state observer is developed for the above-mentioned control strategies. Furthermore, the stability of the controller is tested and the performance of the controller is compared with the classical proportional–integral controller based on disturbance rejection, robustness and tracking capability in a highly non-linear wind speed variation scenario. Modelling, control and comparison are conducted in the MATLAB ® /Simulink ® environment. Finally, a real-time hardware set-up is presented using the dSPACE ds-1104 R&D processing board to validate the control scheme. From the result of the experiments, it is seen that the proposed controller takes 10–15 control cycles to settle to its steady-state values, depending on the control loop, whereas the conventional proportional–integral controller takes 60–75 control cycles. As a result, the settling time for the proposed control scheme is shorter than that of the proportional–integral controller. [ABSTRACT FROM AUTHOR]

Just recently, wind energy continues to be one of most important renewable energy resources, by cause of its production is ecologically friendly; for that reason, the technology built for the renewable energy production by way of wind turbines takes excessive challenges in the study. Due to several physical domains prevailing in wind turbine, namely aerodynamical, mechanical and electrical, the modeling of wind turbine is problematic; thus, modeling based on physical techniques has a superior reliability in these circumstances. One of these approaches is bond graph modeling that model system evolved from conservation law of both of mass and energy comprising in the structures. This study presents modeling the parts of bond graph-based wind turbine. Then, sub models are connected together to attain the entire model of wind turbine for simulation based on 20-Sim software. The proposed wind turbine is 2.5 kW of variable velocity wind turbine with three blades, gearbox, tower, and doubly-fed induction generator type. The effectiveness of bond graph modeling system on wind turbine has been proven in simulation results. [ABSTRACT FROM AUTHOR]

This paper presents a new nonlinear control for the overall model of a three-blade horizontal axis variable speed wind turbine (VSWT) including mechanical and electrical parts, with the aim of improving its performance and making it more profitable. The proposed control is an extension of the classical sliding mode control (SMC) by converting its sliding surface into a sliding sector. The classical SMC approach is widely used for nonlinear systems due to its stability against parameter variation, it is robustness against modeling uncertainties, its good results against external disturbances, and its ease of implementation in real time. Unfortunately, the SMC has a major drawback related to the chattering phenomenon. This phenomenon is due to the utility of a higher switching gain in the case of large uncertainties, it causes high-frequency oscillations once the sliding regime is reached, and it can cause a loss of accuracy by influencing the input control variables. This is the reason that aims to develop a new control law to eliminate the chattering and to guarantee stability, which is demonstrated by the Lyapunov theory. The effectiveness of the developed control is compared with the SMC and is illustrated by numerical simulations using MATLAB toolboxes. [ABSTRACT FROM AUTHOR]

In the field of generation systems, system performance, and power quality are greatly affected by traditional control techniques based on proportional-integral (PI) controllers, which are affected by internal and external factors. Wind power conversion systems based on doubly-fed induction generators are exposed to certain nonlinearities, uncertainties, and external disturbances. From another side, the extraction of the mechanical wind energy required a high-performance control system. This study proposes a robust nonlinear chattering-free third-order sliding mode control (TOSMC) based power control applied to fix its primary disadvantages which are the chattering phenomena and active and reactive power ripples. To show the potential of the proposed TOSMC control, a comparison study considering the TOSMC control, traditional sliding mode control, and the other existing controls is done in terms of power ripples, harmonic distortion of stator current, robustness, and response time. To ensure maximum power extractions and to protect the system, the maximum point power tracking technique based on TOSMC and the proposed control are also implemented. In addition, These techniques are used to control the stator powers. Finally, simulations (using Matlab software) are performed using different wind speeds with durability testing. The simulated results show that the proposed TOSMC control with the MPPT-TOSMC technique in this paper achieves satisfactory results in terms of reducing power ripples, response time, and harmonic distortion of stator current compared to the sliding mode control, where the harmonic distortion reduction ratio of the current was (50.24%) and the active power ripple reduction ratio (47.50%) and the reactive power (46.68%).

The large-scale integration of doubly-fed induction generator (DFIG) based wind power plants poses stability challenges for power system operation. This study investigates the transient stability and dynamic performance of a modified 3-machine, 9-bus Western System Coordinating Council (WSCC) system. The investigation was conducted by connecting the DFIG wind farm to the sixth bus via a low-impedance transmission line and installing power system stabilizers (PSSs) on all automatic voltage regulators (AVRs). A three-phase fault simulation was carried out to test the system, with and without power system stabilizers and a static synchronous compensator (STATCOM) device. Time-domain simulations demonstrate improved transient response with PSS-STATCOM control. A 50% reduction in settling time and 70% decrease in power angle undershoots at the slack bus are achieved following disturbances, even at minimum wind penetration levels. Load flow analysis shows the coordinated controllers maintain voltages within 0.5% of nominal at 60% wind penetration, while voltages at load buses can deviate up to 15% without control. Eigenvalue analysis indicates the PSS-STATCOM boosts damping ratios of critical oscillatory modes from nearly 0% to over 30% under high wind injection. Together, the present findings provide significant evidence that PSS and STATCOM cooperation enhances dynamic voltage regulation, angle stability, and damping across operating ranges, thereby maintaining secure operation in systems with high renewable integration.

This paper presents a novel hybrid type-2 fuzzy sliding mode control approach for regulating active and reactive power exchanged with the utility grid by a doubly-fed induction generator in a wind energy conversion system. The main objective of this hybridization is to eliminate the steady-state chattering phenomenon inherent in sliding mode control while improving the transient delays caused by type-2 fuzzy controllers. In addition, the proposed control approach has proven to be successful in coping with varying generator parameters and exhibited good reference tracking. An in-depth comparative study with state-of-the-art advanced control techniques is also the focus of the present paper. The comparative study has three objectives, namely: a qualitative comparative study that aims to compare response times and reference tracking capabilities; a quantitative evaluation that takes into account time-integrated performance criteria; and finally, robustness capabilities. The simulation results, carried out in the Matlab/Simulink environment, have demonstrated the effectiveness and best performance of the proposed hybrid type-2 fuzzy sliding mode control with respect to other advanced techniques included in the comparison study.

Abstract In order to improve the stability of doubly‐fed induction generator (DFIG)‐based wind turbines under weak grid, previous works have proposed the power synchronization control strategy in the rotor side converter (RSC). However, the potential instability risk of dc‐link voltage control in the grid side converter (GSC) has been neglected. Here, DFIG with power synchronization and phase‐locked synchronization for RSC and GSC respectively, is called as hybrid synchronization mode (HSM)‐controlled DFIG and, the full‐order state space model of HSM‐controlled DFIG are established. Eigenvalue and participation factor analysis shows that the HSM‐controlled DFIG is unstable under extremely weak grid due to the interaction of phase‐locked loop (PLL) and current‐loop in GSC. Furthermore, dominant pole analysis indicates that the HSM‐controlled DFIG exhibits weak damping at the AC side in strong grid. To enhance the stability of HSM‐controlled DFIG under extremely weak grid, an improved hybrid synchronization control strategy is proposed. The improved control strategy utilizes active power and dc‐link voltage to achieve PLL‐free operation of DFIG. The effects of the parameters in dc‐link voltage synchronous loop on control bandwidth, system stability and dynamic coupling are analysed. Finally, the validity of the theoretical analysis is investigated with experiments based on 2MW control‐hardware‐in‐loop platform.

This research work focuses on addressing the challenges of controlling a wind energy conversion system (WECS) connected to the grid, particularly when faced with variable wind speed profiles. The system consists of a Doubly-Fed Induction Generator (DFIG) connected to the grid through an AC/DC/AC converter, along with a Li-ion battery storage system connected to the Back-to-Back converter DC link via a DC/DC converter. The non-linearity and internal parametric variation of the wind turbine can negatively impact energy production, battery charging performance, and battery lifespan. To overcome these issues, the study proposes a robust control approach called Integral action Sliding Mode Control (ISMC) to enhance the dynamic performance of the WECS based on DFIG. Additionally, the battery charging and discharging controllers play a crucial role in efficiently distributing power to the grid and storage unit based on the battery's state of charge, extracted energy, and power injected into the grid. Two current regulation modes, buck charging and boost discharging, are employed to ensure proper energy distribution. Furthermore, a storage system energy management algorithm is implemented to ensure battery safety during one of the charging modes. The effectiveness and robustness of the proposed control method were validated through simulations of a 1.5 MW wind power conversion system using Matlab/Simulink. The results confirmed the method's efficiency and efficacy.

In this paper, we present a novel design and development of wind energy conversion systems (WECS) for a doubly-fed induction generator (DFIG). A hysteresis current control is used to improve the DC bus for rectifier and smart current control by model predictive of three-level-NPC (3LNPC) inverter. The advantages of this intelligent method are such as fast dynamic answers and the easy implementation of nonlinearities, and that it requires fewer calculations to choose the best switching state. In addition, an innovative algorithm is proposed to adjust the current ripples and output voltage harmonics of the wind energy conversion system. The performance of the system was analysed by simulation using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

The wind turbine generators (WTG's) incapability of primary frequency support during system contingencies due to its decoupled nature from the system frequency causes profound integration and stability issues. The present study focuses on resolving such issues by enabling the WTGs to participate in long-term frequency support under the derated operation of WTGs. The deloading operation of WTGs can provide a specific reserve power margin by reducing its rotor speed, which can be utilized during system contingencies. In literature, linear and quadratic deloading techniques have been proposed but these fail to replicate the nonlinear characteristics of the WTG accurately, thereby making deloading ineffective. To effectively implement the deloading, this work uses a more-accurate higher-order Newton's interpolation polynomial (HNIP), to cope with the highly nonlinear characteristics of WTG. The proposed deloading approach is also augmented with a fuzzy-based intelligent supplementary control structure to handle the inherent and incorporated nonlinearities in WTG. The microgrid system, consisting of a conventional energy source with WTG, has been considered as system under investigation. The integral time absolute error for step wind profile and variable speed wind profile was found to be improved by 97.65% and 97.29%, respectively, with the proposed novel deloading technique with fuzzy-PID compared to PID. Further, to ensure the implementation viability of the proposed control scheme, real-time validation of the same is carried out on OPAL-RT 4510, having a Xilinx Kintex-7 FPGA board. It was found that for all the scenarios considered for real-time digital simulation purposes, the results unerringly matched with MATLAB/Simulink. [Display omitted] • Design and implementation of novel nonlinear deloading strategy for WTG. • Implementation of nonlinear fuzzy control structure as supplementary controller. • Real-time validation of proposed novel scheme on OPAL-RT 4510 for investigated MGS. [ABSTRACT FROM AUTHOR]

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Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The large-scale integration of doubly-fed induction generator (DFIG) based wind power plants poses stability challenges for power system operation. This study investigates the transient stability and dynamic performance of a modified 3-machine, 9-bus Western System Coordinating Council (WSCC) system. The investigation was conducted by connecting the DFIG wind farm to the sixth bus via a low-impedance transmission line and installing power system stabilizers (PSSs) on all automatic voltage regulators (AVRs). A three-phase fault simulation was carried out to test the system, with and without power system stabilizers and a static synchronous compensator (STATCOM) device. Time-domain simulations demonstrate improved transient response with PSS-STATCOM control. A 50% reduction in settling time and 70% decrease in power angle undershoots at the slack bus are achieved following disturbances, even at minimum wind penetration levels. Load flow analysis shows the coordinated controllers maintain voltages within 0.5% of nominal at 60% wind penetration, while voltages at load buses can deviate up to 15% without control. Eigenvalue analysis indicates the PSS-STATCOM boosts damping ratios of critical oscillatory modes from nearly 0% to over 30% under high wind injection. Together, the present findings provide significant evidence that PSS and STATCOM cooperation enhances dynamic voltage regulation, angle stability, and damping across operating ranges, thereby maintaining secure operation in systems with high renewable integration. [ABSTRACT FROM AUTHOR]

Aiming at the problem of poor control effect of grid-side converter of doubly-fed induction generator due to load change and filter parameter perturbation, a double closed-loop control strategy of grid-side converter based on extended state observer (ESO) and sliding mode control is proposed. The inner loop adopts ESO-based sliding mode direct power control with power as the state variable, and the outer loop adopts ESO-based sliding mode control with voltage square as the state variable. Using ESO to estimate the system state variables and lumped uncertainties including unmodeled dynamics, load variation and filter parameter perturbation of the system, the sliding mode control method can be designed without the accurate mathematical model of the system to realize the robust control of grid-side converter in a complex environment. In addition, the power difference feedforward link is introduced to reduce the impact of the nonlinearity of the outer loop sliding mode control when the load changes. Finally, two examples of load charge and filter parameter perturbation are simulated, and the results show that the proposed control strategy has stronger robustness in the complex environment than traditional vector control and sliding mode control.

While the doubly fed induction generator (DFIG) is widely applied in the new power system, its decoupled control and fluctuation of output power have led to serious problems in frequency stability. Inertia response control (IRC) of DFIG has attracted significant attention, while its impact has not been clearly researched. In this study, a low-order model of DFIG focusing on frequency stability is proposed. Firstly, the simplified model of DFIG considering the IRC is introduced through Taylor series expansion. The frequency response model considering the energy storage system (ESS) is proposed. Taking the rate of change of frequency (RoCoF) and steady-state frequency deviation (SFD) as the constraint, an analytical solution for the maximum proportion of DFIGs is deduced to reflect the impact of IRC on the system frequency stability. Finally, the accuracy of the proposed method and the effectiveness of IRC is verified on the modified IEEE-9 system.

Renewable Energy Sources have considerably expanded in recent years to address the widening energy deficit in modern power systems. Integrating these sources raises significant concerns for power system management, with transient stability constraints of networks being one of the growing issues for engineers and researchers. In this paper, the impact of Doubly Fed Induction Generators integration is analyzed to examine the transient stability on two test models. A Coupling Strength Index formulated from Network Structural Characteristics Theory is explored to detect the weakest transmission line. This method identifies line 7 to 8 and 5 to 6 as the weakest line with coupling strength index of 0.02739 and 0.105158 for IEEE 9 and 39 bus system, respectively. The system’s transient stability is then investigated with and without the Doubly Fed Induction Generators, considering a three-phase short-circuit fault applied at the middle of the identified line. Several characteristics associated with the system such as generator speed, rotor angle, and electric power were investigated. The simulation was carried out using DIgSILENT Power Factory and the results indicate that the systems are negatively impacted by the integration of Doubly Fed Induction Generators.

In order to improve the stability of doubly‐fed induction generator (DFIG)‐based wind turbines under weak grid, previous works have proposed the power synchronization control strategy in the rotor side converter (RSC). However, the potential instability risk of dc‐link voltage control in the grid side converter (GSC) has been neglected. Here, DFIG with power synchronization and phase‐locked synchronization for RSC and GSC respectively, is called as hybrid synchronization mode (HSM)‐controlled DFIG and, the full‐order state space model of HSM‐controlled DFIG are established. Eigenvalue and participation factor analysis shows that the HSM‐controlled DFIG is unstable under extremely weak grid due to the interaction of phase‐locked loop (PLL) and current‐loop in GSC. Furthermore, dominant pole analysis indicates that the HSM‐controlled DFIG exhibits weak damping at the AC side in strong grid. To enhance the stability of HSM‐controlled DFIG under extremely weak grid, an improved hybrid synchronization control strategy is proposed. The improved control strategy utilizes active power and dc‐link voltage to achieve PLL‐free operation of DFIG. The effects of the parameters in dc‐link voltage synchronous loop on control bandwidth, system stability and dynamic coupling are analysed. Finally, the validity of the theoretical analysis is investigated with experiments based on 2MW control‐hardware‐in‐loop platform. [ABSTRACT FROM AUTHOR]

In this paper, a wind power system based on a doubly-fed induction generator (DFIG) is modeled and simulated. To guarantee high-performance control of the powers injected into the grid by the wind turbine, five intelligent super-twisting sliding mode controllers (STSMC) are used to eliminate the active power and current ripples of the DFIG. The STSMC controller is a high-order sliding mode controller which offers high robustness compared to the traditional sliding mode controller. In addition, it reduces the phenomenon of chattering due to the discontinuous component of the SMC technique. However, the simplicity, ease of execution, durability, and ease of adjusting response are among the most important features of this control compared to some other types. To increase the robustness and improve the response of STSMC, particle swarm optimization method is used for this purpose, where this algorithm is used for parameter calculation. The simulation results obtained using MATLAB software confirm the characteristics of the designed strategy in reducing chattering and ensuring good power control of the DFIG-based wind power. [ABSTRACT FROM AUTHOR]

As the trend towards the decentralization of grids continues, new typologies such as microgrids have gained popularity in recent years. Microgrids offer greater reliability as they can operate both connected to the main grid and in islanded mode. However, the transition to island mode can be even more challenging when a microgrid has a high penetration of intermittent sources like Doubly-Fed Induction Generators (DFIGs). In this context, designing new controller algorithms is essential to improve frequency support in microgrids with DFIGs. Therefore, this paper proposes a novel Filtered Repetitive Model Predictive Control (FR-MPC) applied to the frequency support in a microgrid. The control structure is applied to the Grid Side Converter (GSC) of a DFIG, while the DC bus voltage is supplied by a Battery Energy Storage System (BESS). The FR-MPC prediction model uses a state-space model with an embedded repetitive action, which has the capacity to mitigate harmonics of the microgrid. However, the inclusion of the repetitive loop degrades the closed-loop robustness. To overcome this limitation, the prediction model features a robustness low pass filter. Furthermore, this paper presents an analysis of the frequency response and pole map of the key components of the controller: the robustness filter, the repetitive loop, and the control law. Finally, simulation results demonstrate that the proposed controller outperforms both the pure Repetitive MPC (R-MPC) and the Generalized Predictive Control (GPC) in terms of performance.

Article Highlights This work has demonstrated the efficacy of an interval type-2 FLC adjusted PI in regulating wind turbine rotor speed. The suggested control combined the rapid performance of the PI approach and intelligent control adaptive characteristics. The performance of optimum torque and output power is better with fuzzy type-2 than its type-1 and conventional control.

This paper presents the research into the design and performance analysis of a novel five-phase doubly-fed induction generator (DFIG). The designed DFIG is developed based on standard induction motor components and equipped with a five-phase rotor winding supplied from the five-phase inverter. This approach allows the machine to be both efficient and reliable due to the ability of the five-phase rotor winding to operate during single or dual-phase failure. The paper presents the newly designed DFIG validation and verification based on the finite element analysis (FEA) and laboratory tests.

The most widely applied doubly-fed induction generator (DFIG) leads to insufficient frequency regulation ability of power system. The virtual inertia control can adjust the active power of DFIG according to frequency fluctuation. However, the frequent changes in power flow and operating point bring great challenges to traditional virtual inertia controller with fixed parameters. Direct Heuristic Dynamic Programming (Direct HDP) based control parameter regulator is proposed in this paper to obtain the optimal control parameters when the operation condition changes. Compared with the initial parameters, the response has been significantly improved after adaptive optimization by the proposed method when the system operating point changes.

Doubly-fed induction generator (DFIG) of wind generation system is generally located at the end of the distribution power-grid. Under the weak power grid, the grid connection of wind turbines is unstable, and the current quality is poor. Based on DFIG output impedance model, a stability analysis method combined with adaptive control method is proposed in this paper. The DFIG impedance model with power outer-loop is derived based on the virtual synchronous control of DFIG by using adaptive robust control method. Using generalized Nyquist criterion, the impacts of different power grid conditions and control parameters on the system stable operation under virtual synchronous control are analyzed and verified. The proposed control method in this paper is verified by experiments. The proposed control method improves the quality of grid-connected current.

With the increasing utilization of electronic equipment in the power system, sub-synchronous oscillation (SSO) has occurred many times and caused off-grid accidents because of power oscillation. SSO has become one of the main problems that restrict the development of new energy. In this paper, power oscillation in grid-side converters (GSCs) in doubly-fed induction generators (DFIGs) under SSO is studied. Firstly, the influence mechanism of SSO on GSC multipath disturbance is studied. Secondly, the problem of coupling oscillation caused by PLL output errors after coordinate transformation is studied, and the mathematical model of GSC output power considering SSO multipath disturbance is established. By analyzing the oscillation suppression ability of the quasi-resonant controller under variable SSO states, the key influencing factors of SSO for GSC power oscillation suppression strategies are determined. Furthermore, based on the above theoretical analysis and research, an improved PLL is designed to eliminate the influence of its output errors on the disturbance of GSC. At the same time, a DFIG-GSC power oscillation suppression strategy using an adaptive quasi-resonant controller is designed to eliminate the influence of SSO on the multi-path disturbance of GSC. Finally, the effectiveness of the proposed suppression strategy is verified using simulation and experimental results. [ABSTRACT FROM AUTHOR]