Scheduling and control co-design for Networked Wind Energy Conversion Systems

Fieldbus, industrial Ethernet that is simple, reliable, economical, and practical, is widely used in Wind Energy Conversion Systems(WECSs). These techniques belong to the field of networked control systems. Network embedding to Wind Energy Conversion Systems brings many new challenges. Implementing a control system over a communication network causes inevitable time delays that may degrade performance and can even cause instability. This work addresses challenges related to the reliable control of wind energy conversion systems, based on the theoretical framework of networked control systems. A type of WECS with network-induced delay and packet dropout is modeled and adjustable deadbands are explored as a solution to reduce network traffic in WECSs. A method to study the reliable control of WECSs is presented, which takes into account system response as well as the network environment. After detailed theoretical analysis, simulation results are provided, which further demonstrate the feasibility of the proposed scheme.

A Novel Wind Energy Conversion System with Storage for Spillage Recovery

This paper proposes a new system configuration for integrating a compressed air energy storage system with a conventional wind turbine. The proposed system recycles the mechanical spillage of blades and stores it for later electricity generation with assistance from a rotary vane machine. The configuration and operational policy is explained, and a comparative case study shows that the proposed system recovers investment costs through savings on electricity procurement and revenue through power export.

Event-triggered mechanism based robust fault-tolerant control for networked wind energy conversion system

In this paper,a novel robust fault-tolerant control scheme based on event-triggered communication mechanism for a variable-speed wind energy conversion system(WECS)with sensor and actuator failures is proposed.The nonlinear WECS with event-triggered mechanism is modeled based on the Takagi-Sugeno(T-S)fuzzy model.By Lyapunov stability theory,the parameter expression of the proposed robust fault-tolerant controller with event-triggered mechanisms is proposed based on a feasible solution of linear matrix inequalities.Compared with the existing WECS fault-tolerant control methods,the proposed scheme significantly reduces the pressure of network packet transmission and improves the robustness and reliability of the WECS.Considering a doubly-fed variable speed constant frequency wind turbine,the eventtriggered mechanism based fault-tolerant control for WECS is analyzed considering system model uncertainty.Numerical simulation results demonstrate that the proposed scheme is feasible and effective.

A Novel Hybrid MPPT for Wind Energy Conversion Systems Operating under Low Variations in Wind Speed

This manuscript presents a new approach MPPT (Maximum Power Point Tracking) for improving and optimizing the performance of a Wind Energy Conversion System (WECS) operating for small variations in wind speed by combining sliding mode control and fuzzy logic control. The proposed method consists of optimizing the sliding mode controller by the fuzzy controller. The main purpose of the Sliding Mode control-Fuzzy Logic controller (SM-FL) is to ensure the robustness (by eliminating certain disadvantages of the sliding mode control such as the phenomenon of chattering) and the stability of the control system in the case of small variations in conditions atmospheric (here variation of the wind). Our system consists of a wind turbine, a Permanent Magnet Synchronous Generator (PMSG) and a DC-DC boost converter connected to a continuous load. The performances of the method suggested are compared with those of fuzzy logic and fuzzy-Proportional Integral (FL-PI) in term speed of convergence, of tracking time and tracking efficiency. The results of numerical simulation of our system confirmed the best performance of this method.

PMSG Wind Energy Conversion System: Modeling and Control

In this paper, a model of a variable speed wind turbine using a permanent magnet synchronous generator (PMSG) is presented and the control schemes are proposed. The model presents the aerodynamic part of the wind turbine, the mechanic and the electric parts. Simulations have been conducted with Matlab/Simulink to validate the model and the proposed control schemes.

Direct driven wind energy conversion system based on hybrid excitation synchronous machine

A novel direct-drive type wind power generation system based on hybrid excitation synchronous machine（HESM）is introduced in this paper.The generator is connected to an uncontrollable rectifier,and a fully controlled voltage-sourceinverter is used to connect the system to utility grid.An intermediate DC bus exists between the rectifier and inverter.A new control strategy is proposed which achieves the maximum power point tracking（MPPT） with the control of excitation current of HESM and stabilizes the DC link voltage with the control of inverter output current simultaneously.Specially-designed buck circuit is used to control the excitation current of HESM,and grid voltage-oriented vector control strategy is employed to realize the decoupling of the inverter output power.Simulation results and experiment in 3 kW lab prototype show an excellent static and dynamic performance of the proposed system.

OUTPUT MAXIMIZATION CONTROL FOR VSCF WIND ENERGY CONVERSION SYSTEM USING EXTREMUM CONTROL STRATEGY

The energy conversion optimization control strategy is presented for a family of horizontal-axis variablespeed fixed-pitch wind energy conversion systems,working in the partial load region.The system uses a variablespeed wind turbine(VSWT)driving a squirrel-cage induction generator(SCIG)connected to a grid.A new maximum power point tracking(MPPT)approach is proposed based on the extremum seeking control principles under the assumption that the wind turbine model and its parameters are poorly known.The aim is to drive the average position of the operation point close to optimality.Here the wind turbulence is used as search disturbance instead of inducing new sinusoidal search signals.The discrete Fourier transform(DFT)process of some available measures estimates the distance of operation point to optimality.The effectiveness of the proposed MPPT approach is validated under different operation conditions by numerical simulations in MATLAB/SIMULINK.The simulation results prove that the new approach can effectively suppress the vibration of system and enhance the dynamic performance of system.

Current Source Converter Based Wind Energy Conversion Systems

The increase in the installed capacity of wind energy conversion systems(WECS) has triggered the devel-opment of more demanding grid codes and additional requirements on performance.In order to meet these require-ments the industry trend has shifted to full-scale power converter interfaces in modern multi-megawatt WECS.As con-sequence,a wide variety of new power converter topologies and WECS configurations have been introduced in recent years.Among them,current source converter(CSC) based configurations have attracted attention due to a series of advantages like:simple structure,grid friendly waveforms,controllable power factor,and reliable grid short-circuit pro-tection.This paper presents the latest developments in CSC interfaces for WECS and related technologies such as modulation methods,control schemes and grid code compatibility.

Hybrid Control Strategy for Matrix Converter Fed Wind Energy Conversion System

In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.

Oscillation and Conversion Performance of Double-Float Wave Energy Converter

In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency(capture width ratio).Based on the potential flow theory and the higher-order boundary element method(HOBEM), we constructed a threedimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO's damping coefficient for the double-float WEC's capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs.

IoT Enabled Microgrid Framework Using a Novel Dispersal Diffusion Artificial Neural Network Controller for PV Systems and Wind Energy to Minimize Electrical Faults

A system based on a PV-Wind will ensure better efficiency and flexibility using lower energy production.Today,plenty of work is being focussed on Doubly Fed Induction Generators(DFIG)utilized in wind energy systems.DFIG is found to be the best option in the Wind Energy Conversion Systems(WECS)to mitigate the issues caused by power converters.In this work,a new Artificial Neural Network(ANN)is proposed with the Diffusion and Dispersal strategy that works on Maximum Power Point Tracking(MPPT)along with Wind Energy Conversion System(WECS)to minimize electrical faults.The controller focus was not just to increase performance but also to reduce damage owing to any phase to phase fault or Phase to phase to ground fault.To ensure optimal MPPT for the proposed WECS,ANN achieves the optimal PI controller parameters for the indirect control of active and reactive power of DFIG.The optimal allocation and size of the DGs within the distributed system and for MPPT control are obtained using a population of agents.The generated solutions are evaluated and on being successful,the agents test their hypothesis again to create a positive feedback mechanism.Simulations are carried out,and the proposed IoT framework efficiency indicates performance improvement and faster recovery against faults by 9 percent for phase to ground fault and by 7.35 percent for phase to phase fault.

不平衡电网电压下基于无模型自适应控制的WECS控制研究

不平衡电网电压会影响风能转换系统(WECS)的正常并网运行,导致系统输出功率的波动以及输出电流的畸变。此外,在实际的永磁同步风电系统中可能会由于环境温度的变化以及检测误差等原因使得网侧电路参数存在不确定性的问题,如果参数发生改变,传统控制方法的性能将会下降。基于此,提出了一种基于灰色预测的无模型自适应控制(MFAC)方案,以缓解因电路参数不确定性导致的性能下降问题,使控制系统具有更好的抗干扰能力。此外,采用三种独立的控制方法来解决不平衡电网电压下并网输出功率的波动及电流畸变问题。仿真对比结果表明,所提控制策略不仅在电路标称参数下具有良好的静态和动态性能,而且当网侧电感参数变化时,系统的鲁棒性也得到提高,验证了所提方案的优越性。

Ultra-Modified Control Algorithms for Matrix Converter in Wind Energy System

This paper proposes an ultra-modified SSA(symmetric sequence algorithm)of space vector modulation of MC(matrix converter).The ultra-modified technique improves the drawbacks of the modified one where it provides a reduction of the total harmonic distortion for both output voltage and current.Also this paper proposes a modified feed forward controller of the MC with indirect space vector modulation.The modified feed forward provides a solution for the change in the output voltage due to change in wind speed,where it provides a constant output voltage with constant frequency even if the wind speed changed.Some of the advantages of MC are introduced in this paper.These advantages represented in the output frequency of MC which may be greater than the input frequency,controlling rms value of the output voltage and the ability to control the IDF(input displacement factor).At the end of this paper simulation and experimental results are introduced which give a precise proof to the proposed algorithms.

Application of Power Electronics Converters in Renewable Energy

Against the backdrop of global energy shortages and increasingly severe environmental pollution,renewable energy is gradually becoming a significant direction for future energy development.Power electronics converters,as the core technology for energy conversion and control,play a crucial role in enhancing the efficiency and stability of renewable energy systems.This paper explores the basic principles and functions of power electronics converters and their specific applications in photovoltaic power generation,wind power generation,and energy storage systems.Additionally,it analyzes the current innovations in high-efficiency energy conversion,multilevel conversion technology,and the application of new materials and devices.By studying these technologies,the aim is to promote the widespread application of power electronics converters in renewable energy systems and provide theoretical and technical support for achieving sustainable energy development.

A hybrid fuzzy logic-based MPPT algorithm for PMSG-based variable speed wind energy conversion system on a smart grid

Recently,wind power has gained popularity as a sustainable energy source.Wind energy conversion systems(WECSs)can accept fixed speed and variable speed(VS)operations.VS-WECSs are preferable to conventional WECSs because of their higher electricity collection capacity.Maximum power point tracking(MPPT)systems are essential for maximizing the efficiency of wind energy generation in wind turbine(WT)installations linked to power grids.This study introduces a hybrid fuzzy logic controller-based MPPT(FLC-MPPT)for WTs connected to permanent magnet synchronous generators(PMSGs)to accurately determine the maximum power output of WTs.This study employs a three-phase back-to-back converter to link a PMSG to a utility grid.The reference signals for pulse width modulation controllers comprise two-phase system currents.It constructs a converter that can transfer electrical energy in both directions using insulated-gate bipolar transistor technology and is powered by a battery.The machine-side converter uses model predictive control for the present control loop.Given the generator’s susceptibility to changes in wind conditions,this factor is of the utmost importance.A WT simulation was conducted using MATLAB/Simulink and an FLC methodology was employed.The model used a PMSG.Measurements of rotor speed,power,induced voltage,and current were taken in relation to variations in wind speed.The simulation results show that the FLC-MPPT can maximize the output power over a wide range of wind speeds with a higher efficiency of 92.6%and performance of 95.7%.

STUDY ON KINETIC ENERGY BUDGET OF A TYPHOON——THE CONVERSION BETWEEN KINETIC ENERGIES OF DIVERGENT WINDS AND NON-DIVERGENT WINDS

This paper is the Part Ⅱ of studying the budget of kinetic energy of the typhoon No. 7507, with the emphasis on the conversion between the kinetic energy of the divergent winds and that of the non-divergent winds, and its relationship to the heating field. The main findings have been brought out as follows.

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator （DFIG）-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

考虑多能转换及需求响应的系统优化调度研究

多能转换以及电力需求响应是提高能源利用率、减轻系统供能压力、平衡供需两侧的有效途径。考虑多能转换的电力需求响应技术,针对系统中多种能源的相互转换相互替代,结合价格型电力需求响应,来提高系统的供能能力、平抑负荷侧波动、促进系统对风光的消纳。首先,对能源输入、多能转换、多能储能等环节的相关设备进行线性化建模,建立电力负荷多能转换的统一模型,分析由此形成的电能存储特性;其次,基于峰谷分时电价,建立可削减、可转移、可替代3种负荷模型;最后,考虑系统运行的4大约束条件,以系统运行综合成本最低为目标函数,研究考虑多能转换电力需求响应对系统运行的优化作用,通过Yalmip建模语言建模,并调用Cplex求解器进行求解。以目标函数最优求解结果作为依据,来验证模型的有效性与可行性,可以进一步减少系统运行成本,最大限度提升电力系统消纳风电能力。

Three-phase AC-DC Converter for Direct-drive PMSG-based Wind Energy Conversion System

In this paper,a wind energy conversion system(WECS)is presented for the electrification of rural areas with wind energy availability.A three-phase AC-DC converter based on a bridgeless Cuk converter is used for power extraction from the permanent magnet synchronous generator(PMSG).The bridgeless topology enables the elimination of the front-end diode bridge rectifier(DBR).Moreover,the converter has fewer components,simple control,and high efficiency,making it suitable for a small-scale WECS.A squirrel cage induction motor(SCIM)is used to emulate a MOD-2 wind turbine to implement the PMSG-based WECS.A direct-drive eight-pole PMSG is used in this study;thus,a low-input-voltage system is designed.The converter is designed to operate in the discontinuous inductor current mode(DICM)for inherent power factor correction(PFC)and the maximum power point tracking(MPPT)is achieved through the tip-speed ratio(TSR)following.The performance of the developed system is analyzed through simulation,and a 500 W hardware prototype is developed and tested in different wind speed conditions.