Modal Analysis of Grid Connected Doubly-Fed Induction Generators

This paper presents the modal analysis of a gridconnected doubly fed induction generator (DFIG). The change in modal properties for different system parameters, operating points, and grid strengths are computed and observed. The results offer a better understanding of theDFIG intrinsic dynamics,which can also be useful for control design and model justification. Index Terms—Doubly fed induction generator, eigenvalue analysis, nonlinear dynamic model, small-signal stability.Published versio

Application of Unified Power Flow Controller to Improve the Performance of Wind Energy Conversion System

This research introduces the unified power flow controller (UPFC) as a means to improve the overall performance of wind energy conversion system (WECS) through the development of an appropriate control algorithm. Also, application of the proposed UPFC control algorithm has been extended in this research to overcome some problems associated with the internal faults associated with WECS- voltage source converter (VSC), such as miss-fire, fire-through and dc-link faults

Gravitational-Search Algorithm for Optimal Controllers Design of Doubly-fed Induction Generator

Recently, the Gravitational-Search Algorithm (GSA) has been presented as a promising physics-inspired stochastic global optimization technique. It takes its derivation and features from laws of gravitation. This paper applies the GSA to design optimal controllers of a nonlinear system consisting of a doubly-fed induction generator (DFIG) driven by a wind turbine. Both the active and the reactive power are controlled and processed through a back-to-back converter. The active power control loop consists of two cascaded proportional integral (PI) controllers. Another PI controller is used to set the q-component of the rotor voltage by compensating the generated reactive power. The GSA is used to simultaneously tune the parameters of the three PI controllers. A time-weighted absolute error (ITAE) is used in the objective function to stabilize the system and increase its damping when subjected to different disturbances. Simulation results will demonstrate that the optimal GSA-based coordinated controllers can efficiently damp system oscillations under severe disturbances. Moreover, simulation results will show that the designed optimal controllers obtained using the GSA perform better than the optimal controllers obtained using two commonly used global optimization techniques, which are the Genetic Algorithm (GA) and Particle Swarm Optimization (PSO)

A Practical Model and an Optimal Controller for Variable Speed Wind Turbine Permanent Magnet Synchronous Generator

The aim of this paper is the complete modeling and simulation of an optimal control system using practical setup parameters for a wind energy conversion system (WECS) through a direct driven permanent magnet synchronous generator (D-PMSG) feeding ac power to the utility grid. The generator is connected to the grid through a back-to-back PWM converter with a switching frequency of 10 KHz. A maximum power point tracking (MPPT) control is proposed to ensure the maximum power capture from wind turbine, and a PI controller designed for the wind turbine to generate optimum speed for the generator via an aerodynamic model. MATLAB/Simulink results demonstrate the accuracy of the developed control scheme

Wind Power Frequency Control in Doubly FED Induction Generator Using CFMPC-FOPID Controller Scheme

Because the majority of wind turbines operate in maximum output power tracking mode, power system frequency cannot be supported. However, if the penetration rate of wind power increases, the system inertia related to frequency modulation may decrease. In addition, frequency stability will be severely affected in the event of significant disturbances to the system load. Due to the high penetration of wind power in isolated power systems, this study suggests a coordinated frequency management approach for emergency frequency regulation. In order to prevent the phenomenon of load frequency control in doubly fed induction generators (DFIGs), a unique efficient control scheme is developed. The Cascaded Fractional Model Predictive Controller coupled with Fractional-Order PID controller (CFMPC-FOPID) is developed to provide the DFIG system with an efficient reaction to changes in load and system parameters. The proposed controller must have a robust tendency to respond quickly in terms of minimum settling time, undershoot, and overshoot. Nonlinear feedback controllers are designed using frequency deviations and power imbalances to achieve the reserve power distribution between generators and DFIGs in a variety of wind speed conditions. It makes upgrading quick and easy. In Matlab/Simulink, a simulation model is built to test the viability of the suggested approach

PWM Based VSC For Power Quality Assessment of Grid Integrated DFIG-WECS

The socioeconomic indicators are exclusively dependent upon the growth of energy for every country. The rise of population and urbanization on one hand and environmental degradation by fossil fuel sources on the other has realized the world for sustainable sources of energy to meet the energy imbalance. Therefore, high penetration of wind energy is need of the hour to meet the challenge of rising consumption of power. Globally, wind energy trends are witnessing a rapid growth with the passage of time. In this research contribution, the Doubly Fed Induction Generator (DFIG) derived wind power generation has been selected to harness wind energy at variable speed. The uncertain and fluctuating nature of wind flow cause power quality problems. MATLAB simulation model has been designed and response of power quality issues like voltage sag and harmonic distortion is checked both at No load and with load at the point of common coupling (PCC). For smooth integration of wind turbine generator with power grid, pulse width modulated (PWM) voltage source converters (VSC) are used both at the rotor side converter (RSC) and the grid side converter (GSC). Proportional integral (PI) controllers are used along with VSC for high power output

Comparative study of back-stepping controller and super twisting sliding mode controller for indirect power control of wind generator

© 2021 Springer. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s13198-019-00905-7This paper presents the application nonlinear control to regulate the rotor currents and control the active and reactive powers generated by the Doubly Fed Induction Generator used in the Wind Energy Conversion System (WECS). The proposed control strategies are based on Lyapunov stability theory and include back-stepping control (BSC) and super-twisting sliding mode control. The overall WECS model and control scheme are developed in MATLAB/Simulink and the simulation results have shown that the BSC leads to superior performance and improved transient response as compared to the STSMC controller.Peer reviewe

Robusno neizrazito prilagođavanje pojačanja RST regulatora za WECS dvostruko napajani asinkroni generator

This paper proposes a new robust fuzzy gain scheduling of RST controller for a Wind Energy Conversion System (WECS) based on a doubly fed induction generator (DFIG). First, a designed fuzzy gain scheduling of RST controller is investigated, in which fuzzy rules are utilized on-line to adapt the RST controller parameters based on the error and its first time derivative. The aim of the work is to apply and compare the dynamic performances of two types of controllers (namely, Polynomial RST and Fuzzy-RST) for the WECS. A vector control with stator flux orientation of the DFIG is also presented in order to achieve control of active and reactive power of the wind turbine transmitted to the grid and to make the wind turbine adaptable to different constraints. The results obtained by simulation prove the effectiveness of the proposed controller in terms of decoupling, robustness and dynamic performance for different operating conditions.U radu je predloženo novo robusno prilagođavanje pojačanja RST regulatora za sustav za pretvorbu energije vjetra (WECS) s dvostruko napajanim asinkronim generatorom (DFIG). Prije svega istražena je sinteza neizrazitog prilagođavanja pojačanja RST regulatora u kojem su neizrazita pravila iskorištena on-line za adaptaciju parametara RST regulatora koji koristi signal pogreške i njegovu prvu vremensku derivaciju. Cilj rada primjena je i usporedba dinamičkih svojstava dva tipa regulatora (polinomski RST i neizraziti RST) za WECS. Također je prikazano vektorsko upravljanje s orijentacijom statorskog toka DFIG-a za postizanje upravljanja aktivnom i reaktivnom snagom vjetroagregata koja se predaje mreži te za prilagodbu vjetroagregata za različita ograničenja. Rezultati prikupljeni provedenim simulacijama pokazuju efektivnost predloženog regulatora kroz rasrpegnutost, robusnost i dinamičke performanse za različite uvjete rada

A second order sliding power control & resonant filtering approach to mitigate grid unbalance effects on a DOIG wind energy based system

This paper presents a multivariable power control design applied to a DFIG Wind Energy Conversion based System (WECS). The multiple control objectives pursued in this work include not only tracking temporal profiles of active and reactive power grid injection but also regulate some important internal variables like the DC bus voltage. To fulfil these targets a multivariable control scheme is developed following second order sliding mode techniques. This theoretical framework allows synthesizing controllers with attractive features like finite time convergence, robustness against external perturbations and unmodeled dynamics, simple implementation, etc. To endorse the control system with grid support features under voltage unbalances the multivariable SOSM controller is combined with a set of resonant filters. This mixed scheme allows to substantially reduce the oscillations of simple and double grid frequency on the electric torque and the power injected into the grid. The overall performance of this control proposal is evaluated using representative simulations.Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señale