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Summary For large‐scale commercialized wind turbines, using the speed‐torque lookup table is a traditional strategy to achieve optimum tip‐speed ratio tracking. Due to the constraint of the minimum grid‐connected generator speed and the rated generator speed, the strategy can only use the slashes to describe these 2 transition zones. This affects the smoothness of the output power, shrinks the optimum tip‐speed range, and loses the generating energy. Based on an analysis of the nonlinear aerodynamics of the wind turbine, this paper presents a strategy of realizing optimal power generation control that dynamically updates the output torque limit value of the controller. The strategy solves the problems of unmeasurable wind speed and inability to track wind speed and achieves the target of maximum wind energy capture below rated wind speed. Simulation and field test results proved the correctness of the algorithm.

In order to make the ocean energy generator system realize the maximum power under various conditions, this paper proposes a control strategy based on linear active disturbance rejection control algorithm. The output power is mainly affected by the spin-speed of the generator in a nonlinear manner, and this phenomenon is originated from the tip speed ratio state of the turbine blades. This tip speed ratio associated maximum power can be achieved through a coupled control system that adjusts the spin-speed of generator elaborately. The state equations of ocean power generation system are transformed into a standard form to fit the linear active disturbance rejection control. Finally, the simulation model of the system is established by using Matlab/Simulink platform, with a series of input signals for different working conditions. The results verify that the maximum power under control can be effectively attained by a quick tracking of the target speed.

Doubly Fed Induction Generator (DFIG) needs to get adopted to change in wind speeds with sudden change in reactive power or grid terminal voltage as it is required for maintaining synchronism and stability as per modern grid rules. This paper proposes a controller for DFIG converters and optimal tip speed ratio based maximum power point tracking (MPPT) for turbine to maintain equilibrium in rotor speed, generator torque, and stator and rotor voltages and also to meet desired reference real power during the turbulences like sudden change in reactive power or voltage with concurrently changing wind speed. The performance of DFIG is compared when there is change in wind speed only, changes in reactive power and variation in grid voltage along with variation in wind speed.

The basic influence of blade number on power performance via tip loss and the associated optimum speeds for rotors of varying blade number are presented. A top level examination of implications for blade stress and mass follows. Operational and system design issues around rotors of diffrrent balde number including parking strategies, dynamics, the requirement for hinges or teeter systems are considered. Attention is drawn to the recent highly innovative one‐bladed design of ADES. Finally multi‐bladed rotors are briefly discussed.

Following an introduction to basic VAWT concepts, the distinctive and more complex nature of VAWT aerodynamics with its intrinsically variable torque cycle, double cutting of the streamtube and generally more significant role of dynamic stall are presented. The inherently lower rotor Cp and intrinsically lower optimum speed give rise to power and torque issues of a VAWT which are suggested to be central to evaluation of the technology. Examination of specific VAWT designs considers the Flowind 19m design as avoiding torque problems by having a super‐optimal design speed but thereby incurring extra penalty in power performance. This is contrasted with VAWT designs which have power performance commensurate with HAWTs but very high weight and implied associated cost through the high torque associated with an optimal (low) design speed. Niche applications for VAWTs are suggested, the unusual property that VAWTs may generate maximum power in upflows is noted and in a short status review, possible routes to rendering VAWT design more competitive are suggested.

In recent years, Hybrid Wind-Solar Energy  Systems (HWSES) comprised of  Photovoltaic (PV) and wind turbines have been utilized to reduce the intermittent issue of renewable energy generation units. The proposed research work provides optimized modeling and control strategies for a grid-connected HWSES. To enhance the efficiency of the maximum power tracking of a grid-connected wind-driven Doubly Fed Induction Generator (DFIG) integrated with solar Photovoltaic (PV) system, connected to the DC link of the back-to-back converters of the Hybrid Wind-Solar Energy System (HWSES). Stator Flux-Oriented control is utilized to regulate the Grid Side Converter and Rotor Side Converter. The main objective of this paper is to apply the  Maximum Power Point Tracking (MPPT) strategy to wind and solar PV systems to maximize the power extraction and to provide better integration of the hybrid systems into the electrical grids. Perturb and Observe (P&O) and Incremental Conductance (IC) MPPT algorithms are implemented to the solar PV system with varying solar insolation and their performances and efficiencies are compared. For varying wind speeds, Tip Speed Ratio (TSR) and Optimal Torque (OT) MPPT algorithms are implemented and their performances and efficiencies are compared for the hybrid system considering and integrating solar PV system. The optimal torque MPPT algorithm shows better responses when compared to the TSR method. A 2MW simulation model of the HWSES is developed and its performance is analyzed using MATLAB/Simulink environment. The implemented schemes have the advantage of tracking the optimal power output of the HWSES rapidly and precisely. Additionally, the provided schemes effectively control the power flowing through the HWSES and the utility grid, resulting in a quick transient response and enhanced stability performance.

Recently, controlling a wind energy conversion system (WECS) under fluctuating wind speed and enhancing the quality of power delivered to the grid has been a demanding challenge for many researchers. This paper provides a comprehensive review of synchronous generator-based WECSs. This paper will investigate the growth of wind energy in Egypt and throughout the world, as well as the technological and financial significance of wind energy. The block diagram of a typical grid-connected WECS, power control techniques, characteristic power curve-based maximum power point tracking (MPPT), and MPPT techniques are also presented in this study. Moreover, this study compares different power converter topologies for grid-connected and independent WECSs that use a permanent magnet synchronous generator (PMSG).

Variable speed wind turbines (VSWTs) usually adopt a maximum power point tracking (MPPT) method to optimize energy capture performance. Nevertheless, obtained performance offered by different MPPT methods may be affected by the impact of wind turbine (WT)’s inertia and wind speed characteristics and it needs to be clarified. In this paper, the tip speed ratio (TSR) and optimal torque (OT) methods are investigated in terms of their performance under different wind speed characteristics on a 1.5 MW wind turbine model. To this end, the TSR control method based on an effective wind speed estimator and the OT control method are firstly presented. Then, their performance is investigated and compared through simulation test results under different wind speeds using Bladed software. Comparison results show that the TSR control method can capture slightly more wind energy at the cost of high component loads than the other one under all wind conditions. Furthermore, it is found that both control methods present similar trends of power reduction that is relevant to mean wind speed and turbulence intensity. From the obtained results, we demonstrate that, to further improve MPPT capability of large VSWTs, other advanced control methods using wind speed prediction information need to be addressed.

A wind energy conversion system needs a maximum power point tracking strategy. In the literature, several works have interested in the search for a maximum power point. Generally, their goals are to optimize the rotation speed or the machine torque and the direct current–direct current or the alternating current–direct current duty cycle switchers. This work presents a comparative study between two maximum power point tracking strategies of a wind energy conversion system. The model of the system is studied and developed. It includes a permanent magnet synchronous generator, a diode rectifier and a three-cell direct current–direct current converter. The direct current–direct current is controlled in order to generate the wind maximum power using the tip speed ratio strategy and optimal torque strategy. The effectiveness of the used strategies control scheme is proved by simulation results using MATLAB/Simulink.

The Maximum power point tracking (MPPT) command makes it possible to find the optimal operating point of the wind generator following variations in the wind. Its principle is based on the automatic variation of the power coefficient to continuously maximize the power of the wind generator. This work is an attempt to study and discuss four most popular types of MPPT techniques such as: Perturbation and Observation (P&O), optimal torque (OT), On-Off control, and tip speed ratio (TSR). The Matlab-Simulink environment is used to analyse and then interpret the simulation results of these algorithms, and therefore show the performance and limitations of each algorithm. The comparison shows the efficiency and the superiority of the OT technique compared to the other MPPTs studied.