Wind Turbine Generator System Research Articles

Fuzzy Robust H∞ Tracking Control For Wind Generator System: LMI approach

This study concerns the tracking control problem of the wind turbine generator system with uncertainties parameters and external disturbances. Based on T-S fuzzy model, a fuzzy observer-based and a fuzzy robust state feedback output tracking control are developed to reduce the tracking error by minimizing the disturbance level caused by the wind speed. Using a Lyapunov function combined with H∞ tracking criteria and a judicious of the famous Young relation, a sufficient stability condition for the robust fuzzy tracking control formulated in terms of linear matrix inequality, which can be very efficiently solved by using LMI optimization techniques. The simulation results are given to show the performance of the observer-based tracking controller.

Multiple-Vector Model Predictive Power Control for Grid-Tied Wind Turbine System With Enhanced Steady-State Control Performance

Direct model predictive control (DMPC) is a promising alternative for power electronics and electric drives. It takes the switching nonlinearity of the power converters and system constraints into consideration, without using an extra modulator. However, its one-switching-vector-per-control-interval character leads to big ripples of the control variables. Therefore, with a similar sampling frequency, its steady-state performance is not satisfying. In this paper, we propose a multiple-vector direct model predictive power control (MV-DMPPC) concept for the grid-side power converter control of a back-to-back converter permanent-magnet synchronous generator wind turbine system, using a fully field programmable gate array based solution. The proposed control scheme is compared with the classical DMPPC and two recently reported DMPPC scheme with duty cycle optimizations. Both simulation and experimental tests validate that the control performances are evidently improved with the proposed MV-DMPPC solution.

Operation and control of a DFIG-based grid-connected WECS using NSC during grid fault and with unbalanced non-linear load

ABSTRACTThis paper proposes a combined feed-forward and selective harmonic compensation-based control scheme for a grid-connected doubly fed induction generator Wind Turbine system using a nine-switch converter (NSC) to improve the performance during grid faults and unbalanced non-linear loading. This is achieved through desired line voltage compensation and/or selective harmonic reduction technique. The two outputs of NSC are controlled such that one functions as a series grid-side converter to inject appropriate voltage in series with stator terminals to maintain the desired stator voltage profile, while the other one functions as a parallel grid-side converter to regulate the DC-link voltage to its reference value irrespective of the direction of flow of rotor power with the conventional rotor side converter. Simulation has been carried out in a MATLAB/Simulink environment. The results show that the proposed scheme ensures the feasibility of improving the Fault Ride Through capability and reducing the undesirable effects of the unbalanced, harmonic content in grid voltage at the Point of Common Coupling.

Brushless doubly‐fed induction machines for wind turbines: developments and research challenges

The brushless doubly-fed induction machine (DFIM) provides an interesting alternative to the commonly applied conventional DFIM in modern multi-megawatt (MW) wind turbines. This study presents a literature survey on the brushless DFIM. The evolution of the cascaded induction machine into the modern brushless DFIM is discussed, as well as several theories explaining this machines complex operating principles. Nowadays, brushless DFIM research is mainly focused on the development of a commercially competitive brushless DFIM-based drive for multi-MW wind turbine applications. An overview of the latest developments in the fields of brushless DFIM modelling, design, and control is provided. Based on this, a qualitative comparison is presented of the brushless DFIM and other well-established generator systems for wind turbines and the challenges for future research are explored.

Low Voltage Ride-through and Research on the Control Strategy of Doubly-Fed Wind Power System

Deep Research in the problem of low voltage right through (LVRT) and over-current of rotor after the wind farm’s voltage dropped. Using the protection scheme of the energy dissipation type Crowbar protection circuit on the DC side can consume excess energy of the DC bus and ease the sharp rise of the DC bus voltage, to realize the low voltage ride-through of the wind power generation system. The simulation results show that after the grid voltage dropped, the Crowbar circuit timely cut off can make the rotor current decay rapidly, and ensure the stability of the wind turbine and wind power generation system. And through the theoretical calculation to make sure the range of the optimal resistance of the Crowbar circuit, and then pick out the several average sample value from this range to carry out simulation analysis, which has practical value and guiding significance.

Nonlinear Direct Control for Three-Level NPC Back-to-Back Converter PMSG Wind Turbine Systems: Experimental Assessment With FPGA

Finite control set model predictive control techniques have been emerged as good alternatives in particularly for multilevel and multiphase power converters, for which switching vectors with multiple magnitudes/directions are available but the modulator or switching table design becomes complex. In this paper, a finite-control-set model predictive direct torque and power control (FCS-DTC-DPC) for grid-tied three-level neutral-point clamped back-to-back power converters in permanent-magnet synchronous generator wind turbine systems is presented and experimentally compared with its counterpart: switching table-based direct torque and power control (ST-DTC-DPC). Both methods have been implemented and verified at a lab-constructed setup with a fully FPGA-based real-time controller. Experimental results confirm that both achieve (equivalently) good control dynamics, whereas FCS-DTC-DPC outperforms ST-DTC-DPC in terms of steady-state control performances at similar switching frequencies but has a higher computational demanding and is more sensitive to system parameter variations.

The Power Grid Probabilistic Vulnerability Evaluation Considering the Stochastic Perturbations of Wind Farm

Considering the stochastic volatility of load and wind farm, stochastic outage rate of generator, based on the combination of Cumulant and Gram-Charlier series (CGC), a new evaluation method for probabilistic vulnerability of transmission network is proposed. Firstly, the three-parameter Weibull distribution is adapted to describe the random variation of wind speed and the probabilistic model for wind turbine generator system is established. And then, in order to avoid complicating convolution and improve the computational speed, the vulnerability index of nodes and branches in power grid is proposed with the combination of Cumulant and Gram-Charlier series. Furthermore, the K-means clustering algorithm is adapted to evaluate the vulnerability of nodes and branches. The simulation results in IEEE30 bus system show that the proposed method can lead to a reliable and effective evaluation result.

Research on the Impact of Double-fed Wind Turbine Generator Drive System Modeling on Torsional Vibration Frequency

With the continuous increase of the wind power development strength in recent years, the rapid wind power development causes a series of problems. Based on the mechanism of the torsional vibration of double- fed wind turbine generator system, this paper researches the impact of the main drive system modeling method on the torsional vibration frequency. This paper first establishes mathematical models of three mass blocks and two mass blocks of the drive system, and then calculates the natural vibration frequency of two kinds of mathematical models by use of the small perturbation method and Dunkerley method, and also obtains the sensitivity of mechanical system parameters to the natural vibration frequency through calculation of the sensitivity, and finally obtains the difference of different mathematical models under different fault conditions through the numerical calculation and example simulation, thus providing a theoretical basis for correctly selecting the mathematical models.

Analysis of Wind Turbine Generation System by Using MATLAB

Analysis of Wind Turbine Generation System by Using MATLAB

Dynamic response regulation of non‐linear feedback linearised wind turbine using a two‐mass model

This study discusses the dynamic response regulation problem for the non-linear wind turbine generator system (WTGS) based on the regional pole placement and geometric control techniques. First, the non-linear model of WTGS is feedback linearised into a linear-form system by the geometric control theory. Through constructing the appropriate diffeomorphism, the key variables of the original system have been remained in the transformed linear system, which sustains that the dynamic response could be adjusted in the transformed linear framework. Due to the multi-input multi-output and high-order characteristics, the regional pole placement technique is applied on the feedback linearised WTGS, which can guarantee the limitation of several performances related to the dynamic response. In such a way, the dynamic response of WTGS can be regulated through the feedback linearisation and regional pole placement techniques. Simulation results for a 2 MW wind turbine show the effectiveness of the proposed method.

Small signal stability analysis for different types of PMSGs connected to the grid

Small signal stability of permanent magnet synchronous generator (PMSG)-based wind turbines connected to the power grid should be studied properly in order to facilitate damping strategy design. In this paper, unified small-signal models for different types of PMSGs are developed to study their small-signal stability. The models are composed of mechanical systems, electrical systems and control systems. A two-mass shaft model for the mechanical system is provided to analyze the dynamic and steady-state behaviors of the wind turbine and generator rotor. Meanwhile, PMSG, converter system and transmission line are separately modeled to build unified small-signal models for three PMSG-based wind turbine generator systems (WTGS). Then, based on unified small-signal models, eigenvalue analysis is conducted to determine the relation between different oscillation modes and state variables through calculating participation factors. With modal analysis, the developed small signal models are able to find out all types of oscillation modes for PMSGs connected to the power grid, which are subsynchronous oscillation (SSO), subsynchronous control interaction (SSCI) and low-frequency oscillation, including frequency and damping of each oscillation mode. Different initial values of the small signal models can influence both frequencies and damping ratios of oscillation modes, which lay basis for further damping strategy study.

Conception optimization and CFD structure study of Wind firm power generation based on OWC-WTGS combined generation system with battery storage system

In this paper, a deep study and optimization process for wind firm generation system based on full solar, wind and OWC chamber structure for wave energy harvesting and battery storage system, a combined WTGS (wind turbine generation system) with OWC (oscillating water column chamber) hybrid generation system has been involved for offshore generation firms for power lifting, an FEM (finite element modeling) structure study has been applied to a novel proposition using double orifice chamber structure with form optimization for the maximization of the harvested power, a CFD (Computational fluid dynamics) simulator software module was used for the study of the pneumatic power evolution through the structure. A novel wave generation method was applied to a 1:30 mechanical prototype that was built for this purpose to get an oscillated wave model through the RWMD method (Real Wave Model Simulator) instead of using an ordinary sin wave generator on the tank to make the waves the closest possible to the real sea waves. An experimental energy management system has been implemented for the battery storage energy control using two phase interleaved electronic system for the battery charging process between this latter and the full system. A DC-DC converter for the management of the global power system has been studied for this purpose.

Techno‐economic analysis of a PV–wind–battery–diesel standalone power system in a remote area

The global acceptance of solar and wind resources for power generation has continued to increase due to the fluctuation of world oil and gas prices, recent advances in technology, high prices of fossil fuels, no direct greenhouse gas emission from solar and wind resources and government policies to support utilisation of renewable energy resources (RESs). In recent times, RESs have become a potential alternative to supply electricity to the rural communities where the extension of transmission and distribution lines is difficult due to technical and financial barriers. In view of this, this study deals with the optimisation of net present cost (NPC), fuel cost, operation cost and cost of energy (COE) of the hybrid system which consists of photovoltaic (PV), wind turbine generator (WTG), diesel generator and battery storage system. A hybrid power system is designed in this research work to serve a remote community. The optimisation of the key performance indicators of the proposed hybrid power system is done by using the hybrid optimisation model for electric renewable (HOMER). The results obtained from this research work are analysed to select the best options among the available configurations based on the lowest NPC and COE produced by each configuration. The simulation results from several case studies show that incorporation of PV and WTG have reduced the operating cost of the system.

Artificial Intelligence-Based Fault Tolerant Control Strategy in Wind Turbine Systems

Power converters play an important role as an enabling technology in the electric power industry, especially in Wind Energy Systems (WESs). Where there ensure to regulate exchanging powers between the system and the grid. Therefore; any fault occurs in any parts of these converters for a limited time without eliminating, it may degrade the system stability and performance. This paper presents a new artificial intelligence-based detection method of open switch faults in power converters connecting doubly-fed induction (DFIG) generator wind turbine systems to the grid. The detection method combines a simple Fault Tolerant Control (FTC) strategy with fuzzy logic and uses rotor current average values to detect the faulty switch in a very short period of time. In addition, following a power switch failure, the FTC strategy activates the redundant leg and restores the operation of the converter. In order to improve the performance of the closed-loop system during transients and faulty conditions, current control is based on a PI (proportional-integral) controller optimized using genetic algorithms. The simulation model was developed in Matlab/Simulink environment and the simulation results demonstrate the effectiveness of the proposed FTC method and closed-loop current control scheme.

Reduction in Power OutpuFluctuations and Platform Motions in a Floating Offshore Wind Turbine-Generator System by Model Predictive Control

Reduction in Power OutpuFluctuations and Platform Motions in a Floating Offshore Wind Turbine-Generator System by Model Predictive Control

Aero-Elastic-Control Coupled Analysis of a Vertical Axis Wind Turbine-Generator System

Aero-Elastic-Control Coupled Analysis of a Vertical Axis Wind Turbine-Generator System

垂直軸型風力発電システムの空力-弾性-制御連成解析

垂直軸型風力発電システムの空力-弾性-制御連成解析

Reduction in Power Output Fluctuations and Platform Motions in a Floating Offshore Wind Turbine-Generator System by Model Predictive Control

Reduction in Power Output Fluctuations and Platform Motions in a Floating Offshore Wind Turbine-Generator System by Model Predictive Control

Aero-Elastic-Control Coupled Analysis of a Vertical Axis Wind Turbine-Generator System

Aero-Elastic-Control Coupled Analysis of a Vertical Axis Wind Turbine-Generator System

A Review of Methods to Increase the Availability of Wind Turbine Generator Systems

Availability is an important factor to be considered when designing wind turbine generator systems. The quest for increasing availability is based on the following five design approaches - design for component reliability, active control for reliability, design for fault tolerance, prognostics, and design for maintainability. This paper reviews methods focussing on the first three, i.e. component reliability, active control, and fault tolerance. The paper further identifies some promising directions for further research.