Coordinated Control of Multi-FACTS to Enhance the Dynamic Stability of the Power System

This article introduces a FACTS coordinated control strategy with impedance/admittance measurement feedback. Then the effectiveness of this method is proved in mathematics with damp torque method. The control strategy effect is verified in a single machine infinite bus system and a four machine power system with PSASP6.26 (Power System Analysis Software Package). This coordinated control strategy has practical significance to improve system dynamic stability and theoretical significance to improve system transient stability.

MULTI-FIGHTER COORDINATED MULTI-TARGET ATTACK SYSTEM

A definition of self-determined priority is used in airfight decision firstly. A scheme of grouping the whole fighters is introduced, and the principle of target assignment and fire control is designed. Based on the neutral network, the decision algorithm is derived and the whole coordinated decision system is simulated. Secondly an algorithm for missile-attacking area is described and its calculational result is obtained under initial conditions. Then the attacking of missile is realized by the proportion guidance. Finally, a multi-target attack system. The system includes airfight decision, estimation of missile attack area and calculation of missile attack procedure. A digital simulation demonstrates that the airfight decision algorithm is correct. The methods have important reference values for the study of fire control system of the fourth generation fighter.

Coordinated Control Architecture for Motion Management in ADAS Systems

Advanced driver assistance systems(ADAS) seek to provide drivers and passengers of automotive vehicles increased safety and comfort. Original equipment manufacturers are integrating and developing systems for distance keeping, lane keeping and changing and other functionalities. The modern automobile is a complex system of systems. How the functionalities of advanced driver assistance are implemented and coordinated across the systems of the vehicle is generally not made available to the wider research community by the developers and manufactures. This paper seeks to begin filling this gap by assembling open source physics models of the vehicle dynamics and ADAS command models. Additionally, in order to facilitate ADAS development and testing without having access to the details of ADAS, a coordinated control architecture for motion management is also proposed for distributing ADAS motion control commands over vehicle systems. The architecture is demonstrated in a case study where motion is coordinated between the steering and the braking systems, which are typically used only for a single functionality. The integrated vehicle and system dynamics using the coordinated control architecture are simulated for various driving tasks. It is seen that improved trajectory following can be achieved by the proposed coordinated control architecture. The models, simulations and control architecture are made available for open access.

Combined Control Allocation and Sliding Mode Control in the Dynamic Control of a Vehicle with Eight In-Wheel Motors

An eight wheel independently driving steering（8 WIDBS）electric vehicle is studied in this paper.The vehicle is equipped with eight in-wheel motors and a steer-by-wire system.A hierarchically coordinated vehicle dynamic control（HCVDC）system,including a high-level vehicle motion controller,a control allocation,an inverse tire model and a lower-level slip/slip angle controller,is proposed for the over-actuated vehicle system.The high-level sliding mode vehicle motion controller is designed to produce desired total forces and yaw moment,distributed to longitudinal and lateral forces of each tire by an advanced control allocation method.And the slip controller is designed to use a sliding mode control method to follow the desired slip ratios by manipulating the corresponding in-wheel motor torques.Evaluation of the overall system is accomplished by sine maneuver simulation.Simulation results confirm that the proposed control system can coordinate among the redundant and constrained actuators to achieve the vehicle dynamic control task and improve the vehicle stability.

Research on the Influence Factors and Coordinated Control Strategies between Unit and Grid for Isolated Power System

As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated system operation. This paper analyzes the power grid side and unit side influence factors on the isolated power system. The dynamic models which are suitable for islanding operation are applied to simulate and analyze the stability and dynamic characteristics of the isolated power system under the conditions of different load disturbances and governor parameters. With considering the differences of frequency characteristics between the interconnected and isolated power system, the adjusting and optimization methods of under frequency load shedding are proposed to meet the frequency stability requirements simultaneously in the two cases. Not only proper control strategies of the power plant but the settings of their parameters are suggested to improve the operation stability of the isolated power system. To confirm the correctness and effectiveness of the method mentioned above, the isolated system operation test was conducted under the real power system condition, and the results show that the proposed coordinated control strategies can greatly improve stability of the isolated power system.

Coordinated shift control of nonsynchronizer transmission for electric vehicles based on dynamic tooth alignment

Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult challenge because gear shifting may cause discomfort to the occupants.To improve the swiftness of gear shifting,this paper proposes a coordinated shift control method based on the dynamic tooth alignment(DTA)algorithm for nonsynchronizer automated mechanical transmissions(NSAMTs)of EVs.After the speed difference between the sleeve(SL)and target dog gear is reduced to a certain value by speed synchronization,angle synchronization is adopted to synchronize the SL quickly to the target tooth slofs angular position predicted by the DTA.A two-speed planetary NS AMT is taken as an example to carry out comparative simulations and bench experiments.Results show that gear shifting duration and maximum jerk are reduced under the shift control with the proposed method,which proves the effectiveness of the proposed coordinated shift control method with DTA.

Identification and Control of Typical Industrial Process

Many industrial processes such as heating furnaces have over damping dynamic characteristics. Based on an innovative impulse response model, a method of identification and control for the over damping plant is introduced in the paper. The number of parameters of the model is much less than conventional impulse response model. The model based on tuning procedure of numerical optimum PID controller parameters is presented. For an actual instance, a large scale airflow circulatory resistance furnace control system with cascades of time delays is developed. In the system, the optimum PID control is used in the inner loop. A nonlinear PI compensation control is applied in the outer loop. The coordinating control among each output is realized by a fuzzy control strategy. A process surveillance organization monitors running situation of system and tunes controller parameters.

位移无拖曳控制的动力学协调条件研究

针对位移无拖曳控制的可实现性问题及避免推力饱和问题,首先基于位移无拖曳控制动力学方程,推导出位移无拖曳控制系统中连续可变推力推进子系统的最大推力需要满足的基本动力学协调条件。进一步由位移无拖曳控制动力学方程退化得到的切换动力学方程,推导出负刚度加速度函数为线性及非线性函数两种情形下的让步动力学协调条件。针对让步动力学协调条件开展了仿真比对,结果表明,强非线性情形下的让步动力学协调条件比退化的线性情形更加严苛。最后通过分析给出位移无拖曳控制避免推力饱和的、定性的动力学协调条件,并得到仿真校验,即:检验质量初始状态及指令状态应在让步动力学协调条件区域内靠近负刚度力零位,开环系统时间延迟尽可能短,并且控制带宽应折中选择。

基于动态轨迹规划的自动驾驶车辆协同换道方法

传统的多车协同缺乏对目标队列和换道车辆信息的有效利用,为考虑动态信息变化对换道过程的影响,本文提出基于动态轨迹规划的自动驾驶车辆协同换道控制方法。首先,针对自动驾驶环境下单车进入车辆队列的研究场景,提出基于实时动态信息的协同换道控制框架,在考虑换道车辆与目标队列车辆的合作以及换道行为给目标队列带来影响的基础上,构建非换道期间和换道期间的纵向协同控制模型;之后,在换道车辆发出换道请求并满足换道触发条件后,考虑队列纵向协同目标,根据纵向速度变化动态规划每一时刻的期望轨迹,提出基于正弦曲线的动态换道轨迹规划方法,得到安全和可靠的轨迹曲线,并采用模型预测控制的轨迹跟踪控制算法,实现实时轨迹跟踪;最后,通过搭建Prescan-Simulink联合仿真平台,设计多组不同速度工况下的仿真实验,以及设置传统基于前车—跟随策略的控制算法与本文的控制策略进行对比,综合分析换道触发时间、队列稳定时间和速度波动幅度这3项指标,验证本文控制策略的有效性和可行性。仿真结果表明:本文所设计的协同换道控制策略和传统方法相比,队列的平均稳定时间缩短了34%,队列的速度波动幅度保持稳定,并在不同相对速度的工况下,均能够实现车辆安全和高效地换道。

有源前端组网的直流船舶电网高能效运行控制

直流船舶电网为航运业绿色转型提供了有效可行的解决方案。考虑到实际船舶的运行工况,本文提出一种分层协调控制策略,主要用于有源前端组网的直流船舶电网中功率单元协调运行的设备层控制系统和功率层控制系统。其中,设备层控制系统负责实现发电机组转速的无静差跟随与不同容量柴油发电机组间的动态/稳态功率共享;功率层控制系统负责提升母线电压质量,提高系统能效。最后,利用仿真与半实物仿真系统对控制策略进行验证,结果表明该控制策略可有效提高系统运行能效,最高节省约10%的燃油。

级联型混合直流与UPFC的柔性潮流协调控制策略

级联型混合直流输电系统具有能抑制换相失败、传输大容量功率的优势。但当级联型混合直流低端模块化多电平换流器(MMC)采用主从控制时,若系统发生交直流故障或负荷突增,可能会产生电流不平衡问题,导致受端交流侧功率出现大范围反向传输及电压支撑能力下降。为解决该问题并增强受端电网的稳定性,针对级联型混合直流输电系统,提出一种基于统一潮流控制器(UPFC)的柔性潮流协调控制策略。研究了基于柔性交流输电(FACTS)设备统一潮流控制器(UPFC)的级联型混合直流系统柔性潮流控制特性,针对系统故障及大扰动时出现的功率返送及电压稳定性问题,提出基于UPFC的频率支撑策略和基于动态限幅的电压支撑策略。该策略将送端侧故障带来的功率扰动转移到受端交流系统UPFC所在线路,利用UPFC功率补偿能力进行协调,同时基于动态限幅控制策略,采用无功优先控制方式提高换流站无功输出能力。最后,在PSCAD–EMTDC平台搭建了含受端交流系统的级联型混合直流输电系统模型。首先,仿真了LCC直流电流指令值下降过程,结果表明,本文所提基于UPFC的协调控制策略可以有效地减小交流系统频率波动,抑制功率返送现象;其次,仿真了系统负荷突增过程,验证了动态限幅控制策略能更好地提升MMC对交流系统的电压支撑能力;最后,仿真了连锁故障过程,结果表明,所提协调控制策略能有效地实现对系统频率和电压支撑,抑制功率波动,提高了级联型混合直流系统及受端电网的稳定性。因此,本文提出的级联型混合直流与UPFC的柔性潮流协调控制策略具有有效性和可行性。

直流微电网并离网协调控制策略

传统直流微电网协调控制策略在下垂控制中忽略了电源的功率输出边界动态变化对系统的影响,模式切换控制结构复杂且存在非平滑切换的问题。针对此问题,以光储氢直流微电网为研究对象,提出了一种并离网相统一的协调控制策略。首先,提出了一种动态自适应下垂控制策略,通过向基于最小二乘法原理的数据拟合器输入训练数据,拟合输出动态电流边界,实现了自适应调整动态下垂系数及电源运行状态,并简化了传统模式切换过程和控制结构。其次,结合实际工程,提出一种预同步和外环切换控制相结合的改进并离网切换控制策略,有效降低并离网切换过程中的冲击振荡。最后,将自适应下垂控制和改进并离网平滑切换控制融入所提协调控制策略中,进行多源多工况的多种模式切换的仿真。通过仿真验证了所提协调控制策略的有效性。

AFS/DYC协调控制下汽车侧风稳定性研究

针对高速汽车在侧风环境下的气动稳定性问题,基于车辆空气动力学与车辆动力学构建了动态双向耦合模型,通过采用相平面法确定主动前轮转向(AFS)和直接横摆力矩控制(DYC)的工作时机,实现汽车AFS和DYC的协调控制,以改善汽车的操纵稳定性。研究结果表明:在侧风的作用下,有、无协调控制的车辆最大侧向位移分别为0.23 m和1.24 m,最大偏航角分别为1.92°和2.89°;最大侧向位移减小了81.5%,最大偏航角减小了33.5%,汽车的侧风稳定性得到明显改善。

SVG协同双馈风电场的暂态控制策略研究

为了充分考虑装设静止无功发生器(static var generator,SVG)的双馈风电场故障状况下的非线性特性,使用一种参数自适应超扭曲滑模控制器(super-twisting adaptive sliding mode control,STASMC)对多输入多输出(multiple input multiple output,MIMO)系统的零动态(zero dynamics,ZD)方法进行改进,提出一种ZD-STASMC方法来协调控制双馈机组和SVG。使用ZD方法将原始系统部分线性化,简化了控制设计任务。为了进一步提高在参数不确定性和外部扰动下的电压调节能力,将ZD方法与STASMC相结合。通过STASMC构造辅助输入提升了ZD方法的鲁棒性,减少了建模误差和实际过程中各种误差的影响。改进后的ZD方法减小了线性化误差的影响,加强了双馈感应发电机(doubly-fed induction generator,DFIG)的暂态性能。最后,通过算例系统在三相故障下的仿真验证了所提ZD-STASMC控制的有效性。

Adaptive fuzzy sliding mode control for coordinated longitudinal and lateral motions of multiple autonomous vehicles in a platoon

In this paper, the platoon control problem of autonomous vehicles in highway is studied. Since the autonomous vehicles have the characteristics of nonlinearities, external disturbances and strong coupling, a novel adaptive fuzzy sliding coordinated control system is constructed to supervise the longitudinal and lateral motions of autonomous vehicles, in which the fuzzy system is employed to approximate the unknown nonlinear functions. Due to the low sensitivity to disturbances and plant parameter variations, the proposed control approach is an efficient way to handle with the complex dynamic plants operating under un-certainty conditions. The asymptotic stability of adaptive coordinated platoon close-loop control system is verified based on the Lyapunov stability theory. The results indicate that the presented adaptive coordinated platoon control approach can accurately achieve the tracking performance and ensures the stability and riding comfort of autonomous vehicles in a platoon. Finally,simulation test is exploited to demonstrate the effectiveness of the proposed control approach.

微型燃汽轮机发电系统柔性协调控制策略

在微型燃汽轮机发电系统中,转速稳定对于微型燃气轮机的效率、运行安全十分重要,而负荷变化对燃气轮机转速稳定有很大影响。为此,提出了一种针对负荷变化的微型燃汽轮机发电系统柔性协调控制策略。策略将负荷变化引起的转速波动由燃气轮机和变流器共同控制,构成“机-电”协调控制。结果表明,在加快功率动态响应的同时,保障了控制策略的准确性,避免微型燃气轮机系统达到温度限制而转速失稳。

计及多点电池储能系统的电网二次调频协同控制

在“碳达峰•碳中和”国家能源战略变革背景下,大规模可再生能源的加速并网加剧了电力系统对于快速调频资源需求的迫切性,如何充分发挥以电池储能系统(battery energy storage systems,BESS)为代表的新型快速资源在电网调频中的作用是解决该问题的关键。首先,为满足电网各类型调频资源在自动发电控制(automatic generation control,AGC)系统中的接入监视与分类决策需求,提出“域-群-机”三级控制模型架构;然后,从BESS的荷电状态(state of charge,SOC)主动管理出发,提出基于改进的动态调频容量(dynamic available AGC,DAA)的多元集群协同控制策略,以及引入SOC影响因子的多点BESS功率分配策略;最后,结合实际电网的持续扰动工况及模拟跳机扰动工况进行仿真分析,验证了文中所提控制策略的有效性。文中所提策略不但可以显著改善各单点BESS的SOC一致性,而且能够提升电网调频品质。

电动轮驱动汽车空间稳定性底盘协同控制研究

电动轮驱动汽车空间稳定性控制是电动轮驱动汽车设计的重要组成部分在此基础上,提出了一种适用于四轮驱动车的空间稳定性控制方法。本项目以提升电动汽车空间稳定性为研究对象,针对传统空间稳定控制方法的不足,提出基于底盘协同控制的电动汽车空间稳定控制方法。为此,本项目首先分析影响电动汽车空间稳定性的关键因素;其次,建立电动汽车空间稳定整车动力学模型,提出基于底盘协调控制的电动汽车空间稳定控制方法;最后,基于MATLAB/Simulink构建电动汽车空间稳定性仿真平台,对所提出方法进行仿真验证。

基于系统协调度模型的汛限水位分期控制

为协调防洪与兴利的矛盾,提高洪水资源化利用效益,基于改进模糊集方法进行汛期分期,建立系统协调度模型并计算得到汛限水位的动态控制域。以思林水库为例,前、后汛期的汛限水位与发电效益协同贡献度成正比,与防洪风险协同贡献度成反比;为实现系统协调度最大,前、后汛期的汛限水位动态控制域应分别为[435,437]m和[435,438]m,前、后汛期可分别增发电量2169.907×10^(4)、6509.722×10^(4)kW·h,水资源利用量可分别提高0.716×10^(8)、1.079×10^(8)m^(3)。研究成果可提高洪水资源利用效率,为水库安全合理运行提供参考。

基于分布式扩张状态观测器的多飞行器编队控制

为使飞行器群按照期望队形飞行,提出“领导-跟随”架构下的编队控制方法.首先设计分布式扩张状态观测器,从而跟随者能估计虚拟领导者的位置与速度;然后根据观测器输出以及期望队形中的相对位置关系,计算跟随者的期望位置,给出基于动态面控制的位置跟踪控制律,跟随者可跟踪期望位置.借助Lyapunov稳定性理论证明了所设计方法的稳定性,并通过数值仿真验证了其有效性.分布式扩张状态观测器仅需获取虚拟领导者位置的观测值即可同时估计虚拟领导者的位置与速度;该编队控制方法可使队形在空间中的指向与虚拟领导者速度保持一致.