Utilization Rate Of Wind Energy Research Articles

Active power smoothing control strategy of offshore wind power system based on reduced matrix converter

On account of the fluctuation and randomness of wind speed, the output power of wind turbines fluctuates greatly, which may cause the frequency change of the power grid and increase the difficulty of power system dispatching. To solve this problem, an active power smoothing control (APSC) strategy based on RMC for offshore wind power systems is proposed in this paper. Compared with existing wind power converter systems, RMC adopted in this paper has the advantages of compact structure, small volume and high conversion efficiency. Based on the analysis of the exponential moving average (EMA) algorithm, a method for determining active power based on the fuzzy EMA algorithm is proposed. The method adjusts the cycle number N in real-time according to the wind speed, taking into account both the wind energy utilization rate and the smoothing performance of active power. The control principle of offshore wind power generation system (WPGS) based on RMC is analyzed in detail and the coordinated control strategy of RMC and inverter is proposed. Simulation results demonstrate the validity of the proposed method and control strategy.

Distributed resilient fault-tolerant cooperative automatic generation control and multi-event triggering mechanism co-design for wind energy conversion power system

In wind energy conversion power system, some sensor and actuator fall into abnormal condition which may lead to lower wind energy utilization rate and poor system performance or even system collapse. Meanwhile, with the increasing complexity of wind energy conversion power system, more device nodes compete for limited network communication resources, there are time-delays and packets dropout in data transmission, and these may reduce the efficiency of wind energy conversion. Accordingtoaboveconsideration, the multi-event triggering mechanism based distributed resilient fault-tolerant cooperative control scheme for wind energy conversion power system is put forward. A novel model of the wind energy conversion power system is established when the sensor and actuator faults simultaneously. According to Lyapunov stability theory, the sufficient condition for system exponential mean-square stable is obtained. Different from previous fault-tolerant control method, the proposed control strategy considered the wind energy conversion power system with data transmission management under simultaneous stochastic sensor and actuator faults. The simulation demonstrates that the method proposed in this paper is effective and the multi-event triggering mechanism based distributed resilient fault-tolerant controller provides stronger reliability and higher wind energy utilization efficiency.

Maximum Power Point Tracking Based on Wind Speed Prediction

A control method for MPPT (maximum power point tracking) based on wind speed prediction is proposed to address the issue of slow attainment of optimal speed values by wind turbines in variable wind speed conditions in the wind power system. Initially, the wind speed variation value is accurately estimated using the SSA-BP neural network based on historical wind speed data. Subsequently, the MPP (maximum power point) is calculated considering the optimal blade-tip speed ratio, thereby enhancing the tracking speed of the system. Simulation results demonstrate that this method enables real-time estimation of wind speed variation, improves wind energy utilization rate, and maximizes the utilization of wind energy.

Design and Analysis of an Adaptive Dual-Drive Lift–Drag Composite Vertical-Axis Wind Turbine Generator

In this paper, based on the lift-type wind turbine, an adaptive double-drive lift–drag composite vertical-axis wind turbine is designed to improve the wind energy utilization rate. A drag blade was employed to rapidly accelerate the wind turbine, and the width of the blade was adaptively adjusted with the speed of the wind turbine to realize lift–drag conversion. The aerodynamic performance analysis using Fluent showed that the best performance is achieved with a blade curvature of 30° and a drag-type blade width ratio of 2/3. Physical experiments proved that a lift–drag composite vertical-axis wind turbine driven by dual blades can start when the incoming wind speed is 1.6 m/s, which is 23.8% lower than the existing lift-type wind turbine’s starting wind speed of 2.1 m/s. At the same time, when the wind speed reaches 8.8 m/s, the guide rail adaptive drag-type blades all contract and transform into lift-type wind turbine blades. The results show that the comprehensive wind energy utilization rate of the adaptive dual-drive lift–drag composite vertical-axis wind turbine was 5.98% higher than that of ordinary lift-type wind turbines and can be applied to wind power generation in high-wind-speed wind farms.

Distributed parameter model and experimental investigation of galloping piezoelectric energy harvester

A galloping-based piezoelectric energy harvester has been proposed to generate power for wireless sensors using low-speed airflow. The utilization rate of wind energy is improved by optimizing the geometric parameters of the bluff body. The energy collection system’s distributed parameter mathematical model is established by integrating the electromechanical model and aerodynamic model. To verify the model, a wind tunnel test is carried out. A parametric analysis is conducted to investigate the effects of external resistance, wind speed, and bluff body shape on power. When the wind speed is 5.2 m/s and the resistance is 150 kΩ, the power is 3.72 mW.

Evaluation Method for Energy Saving of Sail-Assisted Ship Based on Wind Resource Analysis of Typical Route

Sail-assisted technology can reduce greenhouse-gas emissions by saving the energy consumption of ships with wind energy utilization. The distribution characteristics of marine wind resources are critical to the energy-saving effect of sail-assisted ships. However, due to the lack of effective energy-saving evaluation methods for improving the utilization rate of wind energy, a high potential for wind energy utilization still exists. A novel energy-saving evaluation method based on the wind energy resource analysis of typical ship routes is proposed in this paper. First, a three-degree-of-freedom motion model for sail-assisted ships considering the wing sail forces is constructed. Then, a wind resource acquisition and analysis method based on spatial–temporal interpolation is proposed. On this basis, the wind field probability matrix and wing sail force matrix are established. Ultimately, an energy-saving evaluation method for sail-assisted ships on typical routes is proposed by combining the sailing condition of ships. The case study results show that the energy-saving effect of a wing sail-assisted oil tanker that sailed on the China-to-Middle East route was more than 5.37% in 2021 and could reach 9.54% in a single voyage. It is of great significance to realize the popularization and application of sail-assisted technology, thus improving the greenization of the shipping industry.

Research on 3D Modeling and Dynamic characteristics of wind turbine blade

In order to prevent blade resonance, reduce blade deflection, improve wind turbine power generation efficiency and wind energy utilization rate, the blade model of 3 kW wind turbine is established, and the natural frequency of wind turbine blade is analyzed. Based on the vibration theory, the effects of dynamic stiffening and rotational softening on the natural frequencies of blades are analyzed. Study the change rule of blade vibration mode under rotating speed of 0~300rpm, and analyze the influence of two effects on blade frequency. The results show that at low speed, the rotating softening effect of the blade is obvious, and the vibration frequency decreases; At high speed, the stress stiffening effect is more obvious, the vibration frequency increases, and the coupling vibration has greater destructiveness.

Research on the application of vertical axis wind turbine in subway tunnel

When the subway train is running at high speed in the tunnel, the originally still air in the tunnel is pushed by the train, so that the air in the tunnel is immediately accelerated, and in the same direction as the train travels, which is called the piston effect in the tunnel, also known as Piston wind. The wind speed of the piston wind in the tunnel is 7~9m/s, and the air volume is considerable. The vertical axis wind turbine has the characteristics of small size, low starting wind speed and high wind energy utilization rate, so it can use piston wind to generate electricity to supply power to lighting equipment and advertising lights in the tunnel, so as to achieve the purpose of energy saving and emission reduction.

Investigation on harvesting characteristics of convective wind energy from vehicle driving on multi-lane highway

In the previous study, through the comparison of various highways convective wind energy capturing devices (HCWECDs), it is confirmed that the best wind energy capture device (WECD) structure is the combined turbine (CT). On this basis, this study continues to further study the capture efficiency of WECD and the interaction between WECD and the vehicle in the multi-lane working condition of cars and trucks. Seven different working conditions were selected for the study through the driving conditions of the vehicles and the placement of WECD in the highway. Star CCM + software was used to model and analyze various working conditions. The simulation results are compared, and the results show that the highest power coefficient (Cp) of WECD is 28.2% in seven working conditions; WECD placed in the isolation zone has a low wind energy utilization rate for vehicles other than in the overtaking lane; When two cars are driving opposite each other, the wake affects each other, reducing the impact on WECD; The rotation of WECD has little influence on vehicle driving, but when two vehicles drive opposite each other, it can reduce part of the resistance of vehicle driving for a short time. This study makes a little use of the huge wind energy behind the car body, so there is a huge room for improvement.

Numerical study on aerodynamic performance and noise of wind turbine airfoils with serrated gurney flap

Improving the airfoil aerodynamics of wind turbines is an effective way to raise the wind energy utilization rate and reduce the dependence on fossil fuels. Select a NACA0018 airfoil as a baseline, and a novel serrated Gurney flap (SGF) is proposed to promote the aerodynamic performance of the airfoil. The SST k-ω turbulence model and large eddy simulation are used to numerically simulate the performance of airfoils with Gurney flap (GF) and SGF. The influence of serration geometry parameters on aerodynamics and noise is examined, and the vortex structure is explored to reveal the inherent mechanism. The results show that the SGFs can significantly improve lift coefficient, delay the stall, and greatly reduce the acoustic noise at investigated attack angles. The arrangement of SGF enhances the stability of shedding wakes and lowers the energy losses, leading to better aerodynamic performance and lower noise. ASGF-0.8-6.7 is a preferred scheme for raising airfoil performance with an enhanced lift-to-drag ratio of 8.61%, a delayed attack angle of the stall of 3°, and a maximum noise reduction of 10.2 dB in the radiated noise, compared to the baseline.

Aerodynamic Performance Analysis of Adaptive Drag-Lift Hybrid Type Vertical Axis Wind Turbine

In recent years, with the continuous development of new energy, how to efficiently use wind energy has received more and more market attention. Due to cost advantages, the development of small wind turbines is accelerating. Among them, the design and research of the airfoil design and research of the lift vertical axis wind turbine has matured, but because of the aerodynamic characteristics of the lift airfoil structure, it is impossible to start itself at low wind speed, resulting in the waste of low wind speed energy. Although the drag wind turbine has good self-starting performance, the wind energy utilization efficiency in the high-speed state is inefficient. Each has its own unique shortcomings, which directly affects the marketization of small wind turbines. In order to solve these problems, this paper presents a drag-lift hybrid type wind turbine structure based on an NACA0018 symmetrical airfoil, which can adaptively change the blade shape. This design can keep the blade in the drag shape under static and low speed conditions, and adaptively change the lift shape with the increase of speed. In addition, through the research method of CFD numerical simulation combined with physical experiments, the proposed wind turbine design is studied and analyzed from multiple angles. At the same time, the “6DOF + dynamic grid” setting is used to study the influence of the opening angle factor of the drag-lift hybrid blade on the self-starting performance, and the study shows that the design of the drag-lift hybrid blade proposed in this paper has a higher self-starting torque and lower starting wind speed than the traditional lifting blade, and it is observed that the drag-lift hybrid blade has the best self-starting performance when the opening angle of the blade is 80°. At the same time, the problem of switching the blade morphology of the drag-lift hybrid blade is also analyzed, along with how to use the spring to control all this adaptively. In order to better analyze the advantages of the drag-lift hybrid design proposed in this paper, a wind tunnel test was also carried out using the physical model, and the relationship between the leaf tip speed ratio and the wind energy utilization rate was obtained, which intuitively showed the improvement of the wind energy utilization rate of the drag-lift hybrid design compared with the traditional lift blade.

Wind speed prediction using a hybrid model of EEMD and LSTM considering seasonal features

As a clean and renewable energy source, wind power is of great significance for addressing global energy shortages and environmental pollution. However, the uncertainty of wind speed hinders the direct use of wind power, resulting in a high proportion of abandoned wind. Therefore, the accurate prediction of wind speed is of great significance in improving the utilization rate of wind energy. In this study, a hybrid wind speed prediction model is proposed based on seasonal autoregressive integrated moving average (SARIMA), ensemble empirical mode decomposition (EEMD), and long short-term memory (LSTM) methods. First, the original wind speed data were resampled to obtain wind speed data within time scales of 15, 30, and 60 min. The SARIMA model was used to extract the linear features and nonlinear residual sequences of wind speed time series at different time scales, and EEMD was used to decompose the nonlinear residual sequence to obtain intrinsic mode functions (IMFs) and sub-residual sequences. For the IMFs and sub-residual sequence obtained after decomposition, the LSTM method was used for training, and the predicted IMFs, sub-residual sequence, seasonal time series, and linear time series were integrated to obtain the final prediction wind speed. To verify the superiority of the wind speed hybrid prediction model proposed in this study, the original wind speed data of a large wind farm were used as a case study. Finally, the proposed wind speed hybrid prediction model was compared with other prediction models, verifying that this experimental model has a higher prediction accuracy.

Compressed Air Energy Storage Capacity Configuration and Economic Evaluation Considering the Uncertainty of Wind Energy

The random nature of wind energy is an important reason for the low energy utilization rate of wind farms. The use of a compressed air energy storage system (CAES) can help reduce the random characteristics of wind power generation while also increasing the utilization rate of wind energy. However, the unreasonable capacity allocation of the CAES system results in high capital investment and a long payback period. In order to improve the economic benefits of energy storage, this paper studies the capacity configuration of compressed air energy storage systems under the condition of wind energy uncertainty. First, the typical hourly power distribution of wind power generation was obtained using historical data. Factors such as user load demand, time-of-use price of the power grid, system investment cost, power shortage cost, and power sales revenue were considered. Then, a model was built with the charging and discharging power and gas storage capacity of the CAES system as constraints, and the maximum return on investment and the minimum volume of the gas storage tank as targets. NSGA-II and TOPSIS optimal selection methods were used to solve the problem. Finally, the model was used to optimize a power operation case. The results show that in the case of an hourly load power demand of a factory using 3.2 MW, a wind farm would need to keep four wind turbines running every day, and a compressed air energy storage system with a rated power of 1 MW and a rated capacity of 7 MW would ensure the best project benefit. In this mode, 1.24 × 103 MWh of wind abandoning power could be reduced annually, 2.6 × 104 kg of carbon emissions could be reduced by increasing energy storage within the operation cycle, and the payback period of investment would only be 4.8 years.

Application of Effective Wind Speed Estimation and New Sliding Mode Observer in Wind Energy Conversion System

The wind speed information measured by the wind speed sensor in the wind turbine generator may differ from sufficient wind speed. Therefore, this paper proposes a new effective wind speed calculation method and applies it to the optimal maximum power point tracking (MPPT) of wind energy. After estimating the turbine torque and its rotor speed, the process reverses the turbine’s aerodynamic model. The extended state observer (ESO) based on sliding mode control is used to estimate the aerodynamic torque, which solves complex and challenging tuning of the traditional ESO parameters, and replaces the conventional PI controller, thereby improving the anti-interference and robustness of the system. The sliding mode observer (SMO) is used to estimate the rotor speed. While satisfying the conditions of Lyapunov’s inequality, the design of the SMO is discussed in detail. The wind speed estimation method proposed for evaluating permanent magnet semidirect drive wind turbine and its application performance in maximum power tracking. The simulation was carried out in MATLAB/Simulink; the simulation confirmed that the estimated wind speed under different wind conditions is accurate. Compared with the traditional PI control, the utilization rate of wind energy is increased by 2%, which can be used for the MPPT control of the wind energy conversion system.

Optimal Design of Wind Turbine Blades by Combination of Multi-airfoil Leaf Elements

This paper takes the blades of a large horizontal axis wind turbine as the research object, selects NACA series airfoil elements for combination, arranges and distributes them according to the thickness and curvature of each airfoil, and generates a new blade that is different from a single airfoil. The aerodynamic performance of the two blades was compared and analyzed by using Qblade software to verify the effectiveness of the method, and the wind energy utilization rate was improved while ensuring the strength of the blade roots.

Performance analysis and design of a new-type wind-motor hybrid power pumping unit

Wind energy can replace electric energy to drive pumping units. Wind power generation is used in oil fields, but the energy saving effect is not obvious. This paper proposes a new method of wind energy utilization. Wind energy directly drives pumping unit by new mechanical-hydraulic transmission system without the intermediate conversion into electricity for the first time. This new system can realize hybrid power of wind and electricity and adjust the output energy of the system to meet load requirements. It can effectively address the problems of wind energy utilization and is especially suitable for oil fields in remote areas where electricity is insufficient and its exploitation is difficult. This paper studies the performance of wind-pump system and mechanical-hydraulic system, respectively. Mathematical model is verified by numerical simulation and experiment studies. The economic matching model is established and the parameters of the system are optimized. Finally, this paper puts forward the optimization matching design theory of wind-motor hybrid system. Wind energy utilization rate is higher 60% under optimal parameter combination.

Aerodynamic performance analysis and power generation characteristics experiment of vertical axis wind turbine

AbstractWith the wide application of clean energy, the requirements of this vertical axis wind turbine are higher and higher. A new diagonal spiral blade vertical axis wind turbine is designed and studied. The shape of the new type of wind turbine blade is designed based on the diagonal spiral structure that is common in life, considering the situation of different pitch angles and constructing 11 kinds of prototype machine. In‐depth analysis of the aerodynamic performance of these new wind turbines through simulation calculations shows that the prototype with a pitch angle of 110° has the best aerodynamic performance. When the tip speed ratio is 0.4, the maximum wind energy utilization rate can reach 0.29. Besides, the model of this wind turbine is constructed by 3D printing, which is tested, and the performance of the models is compared with that of the traditional S‐type wind turbine in a real environment. There rationality and superiority of the design of the new diagonal spiral blade vertical axis wind turbine are proved, and this apply background of this new diagonal spiral blade wind turbine is demonstrated by comparison. This article also analyzes the wake of the wind turbine and makes reasonable planning of the arrangement spacing that the wake effect has the least effect on the downstream wind turbine, which can increase the power generation efficiency of the group arrangement of turbines.

Structural optimal design and power generation characteristics of a bionic type nautilus vertical axis wind turbine

Nautilus vertical axis wind turbine is a new breed which is being designed and developed through bionics and geometry, this kind of wind turbine is not only novel in appearance, and stable in structure, but also has excellent aerodynamic performance. Based on this type of wind turbine, combined with its structural characteristics, this paper designed 20 prototypes by continuously adjusting the structural parameters of the spiral blades. The performance of these prototypes is compared by simulation, the optimal structure of this kind of wind turbine is selected. This optimized wind turbine has a strong ability to collect wind energy and can obtain higher wind energy utilization in a wider range of wind speed, the maximum wind energy utilization rate reaches 32.842%. Then the wake characteristics are analysed, the reasonable arrangement is designed. This paper also built an equal scale reduced version of the real object using a 3D printer, and assembles it with a small disc type electric machine to construct a vertical axis wind power generation apparatus. Finally, experiments are conducted in a real environment to analyse the rotational speed and voltage waveform of this apparatus under different operating conditions experimentally.

Investigation on aerodynamic performance of horizontal axis wind turbine by setting micro-plate in front of the blade leading edge

Under the pressure of conventional energy emergency and global environmental degradation, wind energy has been developed and utilized as an important energy source since 1973. However, flow separation occurs on the surface of horizontal axis wind turbine blades under high angle of attack, which reduces the utilization rate of wind energy. To address this problem, a method of setting micro-plate in front of the blade leading edge of the NREL Phase VI wind turbine is proposed, and the effects of the micro-plate at different positions and different plate widths on the aerodynamic performance of the wind turbine are investigated. The results show that distance between the micro-plate and the blade leading edge from the blade thickness direction and the chord length direction have significant effects on the aerodynamic performance of the blade, there is a position where the flow separation control effect is best. While in the same position, the control effect of micro-plate on the flow separation is different with different plate widths, and there is an optimal plate width at certain wind speeds, which makes the flow control effect the best.

Flexibility assessment of a hybrid power system: Hydroelectric units in balancing the injection of wind power

With the increasing scale of wind energy being connected to the power grid, the system flexibility shows an increasingly important role in maintaining the power balance. This trend indicates that it requires a clearer understanding of how the flexibility resource provided by hydroelectric units affects the flexibility performance. It is a challenge for the flexibility assessment as one of the major reasons for the accurate quantification involves the randomness, volatility, and intermittency of wind power injected into the grid. To address this challenge, a mathematical model of a wind-hydro hybrid power system (WHHPS) is developed and verified. The flexibility indices, namely, the probability and expectation of upward/downward flexibility not supplied, are defined. Finally, the flexibility properties of different reserve ratios and line distances are quantitatively analyzed. One of the main results shows that both the upward and downward flexibility are improved with the reserve ratio increasing regardless of changes in wind speed types. The proposed methods and results provide a visualized reference for the dispatching department to evaluate the required flexibility for improving the utilization rate of wind energy.