Integrated strategy for real-time wind power fluctuation mitigation and energy storage system control

To address the impact of wind-power fluctuations on the stability of power systems,we propose a comprehensive approach that integrates multiple strategies and methods to enhance the efficiency and reliability of a system.First,we employ a strategy that restricts long-and short-term power output deviations to smoothen wind power fluctuations in real time.Second,we adopt the sliding window instantaneous complete ensemble empirical mode decomposition with adaptive noise(SW-ICEEMDAN)strategy to achieve real-time decomposition of the energy storage power,facilitating internal power distribution within the hybrid energy storage system.Finally,we introduce a rule-based multi-fuzzy control strategy for the secondary adjustment of the initial power allocation commands for different energy storage components.Through simulation validation,we demonstrate that the proposed comprehensive control strategy can smoothen wind power fluctuations in real time and decompose energy storage power.Compared with traditional empirical mode decomposition(EMD),ensemble empirical mode decomposition(EEMD),and complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)decomposition strategies,the configuration of the energy storage system under the SW-ICEEMDAN control strategy is more optimal.Additionally,the state-of-charge of energy storage components fluctuates within a reasonable range,enhancing the stability of the power system and ensuring the secure operation of the energy storage system.

Extended state observer based smooth switching control for tilt-rotor aircraft

A tilt-rotor aircraft has three flight modes: helicopter mode, airplane mode and conversion mode. Unlike the traditional aircraft, the tilt-rotor aircraft, which combines the characteristics of helicopters and fixed-wing aircraft, is a complex multi-body system with the violent variation of the aerodynamic parameters. For these characteristics, a new smooth switching control scheme is provided for the tilt-rotor aircraft. First, the reference commands for airspeed and nacelle angles are calculated by analyzing the conversion corridor and the conversion path. Subsequently, based on the finite-time switching theorem, an average dwell time condition is designed to guarantee the stability in the switching process. Besides, considering the state vibrations and bumps may appear in switching points, the fuzzy weighted logic is employed to improve the system transient performance. For disturbance rejection, three extended state observers are designed separately to estimate the disturbances in the switched systems. Compared with the traditional auto disturbance rejection control and proportion integration differentiation control, this method overcomes the conservatism of wasting the whole model information. The control performances of robustness and smoothness are verified with simulation, which shows that the new smooth switching control scheme is more targeted and superior than the traditional design method.

A novel coordinated control strategy considering power smoothing for a hybrid photovoltaic/battery energy storage system

This work presents a novel coordinated control strategy of a hybrid photovoltaic/battery energy storage(PV/BES) system. Different controller operation modes are simulated considering normal, high fluctuation and emergency conditions. When the system is grid-connected, BES regulates the fluctuated power output which ensures smooth net injected power from the PV/BES system. In islanded operation, BES system is transferred to single master operation during which the frequency and voltage of the islanded microgrid are regulated at the desired level. PSCAD/EMTDC simulation validates the proposed method and obtained favorable results on power set-point tracking strategies with very small deviations of net output power compared to the power set-point. The state-of-charge regulation scheme also very effective with SOC has been regulated between 32% and 79% range.

Research on semi-active control method of a building structure based on non-smooth control

This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stability theory, it has bene proven that the non-smooth semi-active control algorithm can achieve a finite-time stability of the vibration relative to the isolation layer of a building structure. Through numerical simulation of two buildings with different parameters subjected to the input of a seismic wave, the vibration conditions of passive control, LQR semi-active control and non-smooth semiactive control are compared and analyzed. The simulation results show that the non-smooth semi-active control algorithm has a better robustness and effectiveness in restraining the impact of earthquakes on the structure.

Fast Ferry Smoothing Motion via Intelligent PD Controller

A novel type of control law was adopted to reduce the vertical acceleration of a fast ferry as well as the motion sickness incidence suffered by the passengers onboard by means of a submerged T-foil.Considering the system changing characteristics under high disturbances,a model-free approach was adopted.In addition,an upgraded proportional-derivative(PD)controller with correction terms resulting from a fast-online estimation of the system dynamics was designed.The overall controller,known as intelligent PD(i-PD)controller,was tested,and the obtained results were compared with those of a classic PD controller.The controllers were also tested in a changing environment and at different operating velocities.The results confirmed the effectiveness of the i-PD controller to smooth the motions with low computational cost control schemes.Furthermore,thanks to ability of the i-PD controller to continually update the estimated dynamics of the system,it showed a better reduction in both vertical motions and the seasickness level of the passengers with the needed robustness under external disturbances and system changing parameters.

A Control Strategy for Smoothing Active Power Fluctuation of Wind Farm with Flywheel Energy Storage System Based on Improved Wind Power Prediction Algorithm

The fluctuation of active power output of wind farm has many negative impacts on large-scale wind power integration into power grid. In this paper, flywheel energy storage system (FESS) was connected to AC side of the doubly-fed induction generator (DFIG) wind farm to realize smooth control of wind power output. Based on improved wind power prediction algorithm and wind speed-power curve modeling, a new smooth control strategy with the FESS was proposed. The requirement of power system dispatch for wind power prediction and flywheel rotor speed limit were taken into consideration during the process. While smoothing the wind power fluctuation, FESS can track short-term planned output of wind farm. It was demonstrated by quantitative analysis of simulation results that the proposed control strategy can smooth the active power fluctuation of wind farm effectively and thereby improve power quality of the power grid.

Micro-Grid Smooth Switchover Method Based on Controller State Following

Micro-grid smooth switchover between different operation modes is important for steady operation and reliable power supply of micro-grid. In order to reduce the transient fluctuation of voltage and frequency during switchover, this paper proposed a new switchover method based on controller state following. When transferring to island mode, the control method for inverter of storage device changed from PQ control to V/f control. Before switchover, the output of V/f controller is always following the output of PQ controller. So that the sudden change of output is avoided at the moment of switchover. A micro-grid model with photovoltaic and battery is built on DIgSILENT Power Factory simulation software, to simulate micro-grid switchover from grid-connected mode to island mode. Results show this method can effectively suppress the transient fluctuation of voltage and frequency, and reduce the influence of transient process on power grid. This conclusion has important practical significance on micro-grid smooth switchover from grid-con- nected mode to island mode.

On a novel non-smooth output feedback controller for the attitude control of a small float satellite antenna

A novel non-smooth controller of the second order double integrator system with a bounded disturbance is proposed,which stability is proved and which disturbance rejection capability is analyzed by MATLAB simulation experiments. The novel non-smooth output feedback controller and tracking differentiator are applied to control the azimuth servo systemof the small floating satellite antenna. The MATLAB simulation and hardware in the loop simulation experiments are conducted. The experiment results validate that the non-smooth output feedback controller with stronger surge and sudden disturbance rejection capability can realize the stable azimuth servo control of the small floating antenna to ensure the communication between the target satellite and the antenna with high quality.

基于漏斗函数双电机伺服系统跟踪与同步控制

针对双电机驱动伺服系统具有未知非线性的问题,提出一种基于漏斗函数的跟踪与同步控制方案。首先,利用神经网络逼近和补偿复杂的非线性,在此基础上,引入滤波技术解决传统反步控制的“计算爆炸”问题,同时引入非光滑漏斗误差面确保系统的状态量被约束在预定义的漏斗边界内,结合改进的漏斗函数和反步设计技术设计了一种自适应量化漏斗跟踪控制方案。为了同时保证双电机的同步运行,同步控制器采用了平均偏差耦合策略,实现了双电机伺服系统的跟踪与同步控制。仿真结果表明,该方法可以实现对负载的跟踪以及双电机的同步。

智慧高速铁路运行控制系统发展趋势综述

在保障安全的前提下,高速铁路运行控制系统进一步结合现代感知、控制、通信以及人工智能技术实现智慧化,是未来高速铁路发展的前沿方向。分析目前高速铁路运营中仍存在异物侵限造成安全事故、突发事件导致列车延误、运力与运量不匹配等问题,提出高速铁路运行控制系统的智能化、智慧化是解决上述问题的重要手段,是保持和提升我国高速铁路技术整体竞争力的核心组成部分。新时期的智慧高速铁路运行控制系统以实现列车(群)全天候全无人自主追踪运行控制为目标,主要包括移动闭塞、列车运行净空感知、列车状态智能监测、列车自主追踪、智能调度指挥、车-地动态自组网通信等关键技术。结合新一代使能技术,研究高速铁路运行控制智能技术的应用及其发展趋势,对我国智慧高速铁路的发展具有参考价值。

自动泊车前轮转角闭环的分层控制方案

为提高自动泊车系统中控制器的抗扰动能力,优化控制律执行效果,提出了前轮转角闭环的分层控制方案.设计了以行驶距离为非时间参考量的fal函数非光滑控制律,输出前轮转角控制量.以阿克曼转向模型为基础,建立了前轮转角观测器,并使用模糊滑模控制器实现前轮转角闭环的横向控制.搭建Carsim/Simulink联合仿真系统,在典型泊车场景下验证所设计控制器的有效性、跟踪效果及鲁棒性.使用实车测试平台开展了试验.结果表明:所设计的前轮转角闭环分层控制方案能够快速准确地跟踪目标路径,提高了泊车系统的横向控制精度,并在未知转向非线性扰动下也具有良好的跟踪控制效果.

周边眼偏位空孔爆破设计优化研究与应用

依据已有研究对空孔效应和设置空孔时裂纹扩展规律进行探讨,发现空孔有利于裂纹贯通,对提升爆破效果有一定帮助,但也发现传统的直线型空孔布置会导致裂纹偏向,即在空孔附近转向、偏离原发展路径,影响原设计开挖轮廓。若设置偏位空孔,则可充分利用空孔效应及导向作用以提高开挖质量。对于偏位空孔在爆破中的效应,采用数值模拟研究了不同炮孔间距、空孔偏位角下的裂纹扩展规律和炮孔间贯通情况,探讨了最优偏位角度设计,并根据模拟结果对现场爆破方案进行优化,研究实际应用效果。研究结果表明:偏位空孔对爆生裂纹具有较直线空孔更明显的导向作用,主要表现在爆生裂纹尖端向空孔本身发展或被空孔裂纹引导偏向、最终主裂纹与空孔连通或在空孔范围之外主裂纹相贯通,更利于炮孔主裂纹扩展与贯通;通过提取模拟结果并测量裂纹范围,对于孔间距在60 cm及以下时,适用于周边眼爆破设计的最优偏位角为15°,在此情况下炮孔连线方向形成了与孔心连线相平行的裂纹,能显著提升贯通效果;对于优化后的福厦铁路某隧道爆破施工方案,通过振速监测及超欠挖断面扫描分析,发现周边眼起爆引起的爆破振速降低了超过50%,超欠挖值也由平均25 cm降低至15 cm以内,整体应用效果良好。该项研究可为隧道爆破减振及超欠挖控制研究提供一定参考。

基于模型预测静态规划的高速多体船减纵摇控制

为解决在海浪扰动下高速多体船的垂向稳定性变差问题,提出一种基于模型预测静态规划的减纵摇控制方法。考虑高速多体船模型不确定性、海浪噪声不符合高斯白噪声分布特点,根据噪声信息和误差信息设计平滑变结构滤波器,在线估计多体船的升沉速度、纵摇角速度,并将其引入到减摇控制中。在此基础上,基于模型预测静态规划提出多体船的减摇控制,采用终端偏差修正的求解方式,迭代更新控制输入,降低计算复杂度。最后,仿真实验表明了所提方法能有效抑制过大的升沉和纵摇运动幅度,以及减摇控制计算负荷小的优越性。

基于机网变流器协同的波浪发电系统控制策略

为实现波浪发电系统的高效平稳入网,以直驱式波浪发电装置为例,建立其数学模型和并网结构。将装置输出功率分解为平均分量和波动分量,从发电系统主动式控制的角度,进一步提出了阻尼控制和阻尼弹力控制下的最优策略,以使其高效运行。通过直流侧储能配置及机侧和网侧变流器的协同控制,实现电能的平稳入网。仿真结果表明,阻尼弹力控制较于阻尼控制,发电效率更高同时波动更大,直流侧储能及机网侧协同控制可有效平抑功率波动,为波浪发电系统的入网控制设计提供参考。

基于活动性检测动态估计噪声的心音降噪算法

针对基于小波分解和最优改进对数幅度谱估计的心音降噪算法存在噪声残留和心音失真的问题,提出一种基于心音活动性检测(HSAD)动态估计噪声的心音降噪算法。通过设计的HSAD判断当前心音帧是否为基础心音帧(FHS),根据判断结果分别采用改进最小值控制递归平均(IMCRA)算法和递归平滑算法对噪声功率进行动态估计与更新,采用非因果先验信噪比,实现心音信号的降噪。实验结果表明,提出算法能更好在提升降噪性能的同时,降低FHS的失真。

基于EWT的分布式光储PCC功率波动自适应平抑方法

分布式光伏在交流侧公共连接点(point of common coupling,PCC)汇流的功率有较大的随机性与波动性,影响电网的稳定运行。为此,提出了基于经验小波变换(empirical wavelet transform,EWT)的分布式光储PCC功率自适应平抑方法。首先,针对混合储能(hybrid energy storage system,HESS)与分布式光伏接入PCC的典型场景,在分析EWT自适应处理波形的特点后,结合功率波动率与储能元件的响应特性,对PCC的光伏原始汇流功率进行EWT分解与优化修正,实现HESS的功率初级分配。之后为避免HESS的荷电状态(state of charge,SOC)频繁越限,提出了一种主动功率补偿的SOC控制策略,通过主动改变储能的参考信号使其SOC在安全范围内工作。结合实际数据的仿真验证表明,该平抑方法能够自适应地实现光伏出力的合理分解与功率分配,在延长储能使用寿命的同时有效满足并网功率波动的要求,为平抑光伏输出功率波动提供了新思路。

分区互联配电网异步孤岛模式切换策略研究

大规模分布式电源的存在允许配电网通过网络重构改变供电方式,实现部分区域在必要时刻以异步孤岛形式运行。但配电网运行方式的改变必然伴随着关键换流器控制模式的切换和参数的调整,如何平稳地实现配电分区在并网和孤岛之间的转换是实现有源配电网安全可靠运行的重要内容。针对通过软开关(soft open point,SOP)实现柔性互联的配电分区,分析了该系统由并网转为异步孤岛运行的暂态特性,提出了基于参考功率自适应的改进下垂控制策略,并采用状态跟踪方法降低了配电网运行状态切换时刻的暂态波动,实现了配电网运行方式的平滑切换。在PSCAD/EMTDC环境下搭建了仿真模型进行验证,结果表明,所提控制方法可有效提升分区互联有源配电网运行的灵活性。

四旋翼飞行器的RBF神经网络鲁棒自适应控制

针对具有模型不确定性和有界外部扰动的四旋翼飞行器,提出了一种基于径向基函数神经网络的鲁棒自适应全局控制方法(RRAC)。所提方法结合了神经网络控制对未知非线性的强拟合能力和鲁棒控制的全局稳定性,解决了神经网络控制仅能实现半全局一致最终有界的问题,实现了控制精度和鲁棒性的双重提升。所设计的控制器由在近似域内工作的神经网络控制器和在近似域外工作的鲁棒控制器组成。引入一种新型切换函数来实现两者之间的平滑切换,以保证闭环系统的所有信号是全局一致最终有界的。利用Lyapunov函数和Barbalat引理严格证明了非线性四旋翼飞行器系统的稳定性。仿真表明,所设计的控制器在模型不确定性和有界外部扰动下对参考轨迹依旧保持良好的跟踪性能,且跟踪误差趋近于零。

基于瞬时功率镜像补偿的斜坡式重力储能系统功率平滑控制策略

针对重力储能系统因离散质量块切换引起的输出功率波动问题,提出了一种基于瞬时功率镜像补偿的功率平滑控制策略。首先介绍了斜坡式重力储能系统的工作原理,分析引起系统功率波动的原因;然后设计了抑制功率波动的系统结构以及功率平滑控制策略,并以11 kW的斜坡式重力储能系统为例,对系统结构参数进行理论计算;最后构建斜坡式重力储能系统仿真模型,分析了系统在质量块交替过程中的暂态波动特性。结果表明,应用所提方法,质量块在交替过程中可提供连续稳定的机械功率,较好地平滑重力储能系统的输出功率,验证了该方法的有效性。

基于LADRC的柔性多状态开关平滑切换策略

为实现多端口柔性多状态开关(flexible multi-state switches,FMSS)在所连馈线发生故障时的平滑切换,该文提出一种基于线性自抗扰控制(linear active disturbance rejection control,LADRC)的平滑切换策略,使用LADRC代替比例积分(proportional integral,PI)控制器的直流电压外环并设计解耦状态观测器以便控制器参数调节,引入内环电流指令值反馈以减小其在控制模式切换时的变化幅度,实现FMSS控制模式的平滑切换。通过MATLAB/Simulink仿真,验证了馈线故障出现在PQ或UdcQ控制端口的连接处时,采用基于LADRC的平滑切换策略均可显著减小FMSS的直流电压偏移率,使端口有功功率过渡平滑,迅速恢复稳定,更好地实现了多端口FMSS控制模式的平滑切换。