Research on AC Electronic Load with Energy Recovery Based on Finite Control Set Model Predictive Control

Nowadays,AC electronic loads with energy recovery are widely used in the testing of uninterruptible power supplies and power supply equipment.To tackle the problems of control difficulty,strategy complexity,and poor dynamic performance of AC electronic load with energy recovery of the conventional control strategy,a control strategy of AC electronic load with energy recovery based on Finite Control Set Model Predictive Control(FCSMPC)is developed.To further reduce the computation burden of the FCS-MPC,a simplified FCS-MPC with transforming the predicted variables and using sector to select expected state is proposed.Through simplified model and equivalent approximation analysis,the transfer function of the system is obtained,and the stability and robustness of the system are analyzed.The performance of the simplified FCS-MPC is compared with space vector control(SVPWM)and conventional FCS-MPC.The results show that the FCS-MPC method performs better dynamic response and this advantage is more obvious when simulating high power loads.The simplified FCS-MPC shows similar control performance to conventional FCS-MPC at less computation burden.The control performance of the system also shows better simulation results.

Multi-Channel Force Control System for Static Loading

An eight-channel force loading system is presented, which adopts position control system and force control system switching model, small flow servo valve controlled capacious cylinder system scheme, intelligent PID algorithm and distributed load approach. Through the analyses of the equivalent model of valve controlled cylinder force subsystem, a controller based on intelligent PID algorithm is designed, which is not sensitive to the variation of parameters such as environmental stiffness. According to the coupling of multiple load channels, a distributed load approach is employed in the superior monitor computer. Experimental results show that the system designed has high precision and robustness.

大型燃煤火力发电机组调峰优化控制技术

调峰优化控制可以使得电网的源荷供需处于平衡状态,对提高火力发电机组调峰的稳定性至关重要。为此,提出一种大型燃煤火力发电机组调峰优化控制技术。构建爬坡压力缓解的目标函数,通过对火电机组、失负荷、储能以及光伏发电进行约束,以缓解爬坡压力。构建火力发电机组调峰优化控制的目标函数,结合火力发电机组在运行功率、功率平衡、启停机时间等方面的约束,实现了大型燃煤火力发电机组的调峰优化控制。实验结果表明,文中技术能够缓解大型燃煤火力发电机组的爬坡压力,优化了响应速度。通过所提技术的调峰优化实现了火力发电稳定运行,顺利完成调峰任务。

基于LSTM与迁移学习的配电网负荷频率控制PI参数整定方法

在整定配电网络负荷频率过程中,控制器PI参数会受到局部控制迭代影响,在控制层与反馈层形成时间差量,进而造成频率里程偏差。对此,提出基于LSTM与迁移学习的配电网负荷频率控制PI参数整定方法。采用LSTM模型对调频(FM)里程参数进行模型量化,配合迁移学习对负荷频率控制相关参量进行差分更新,构建配电网负荷频率的LSTM模型,进行频率控制的迁移学习优化、PI参数控制约束及PI参数整定输出。实验结果表明,不论是在控制精度上还是在控制稳定性上,均具有良好的性能表现,整定结果满足预期。

柴油发电机组假负载自动控制系统设计

鉴于柴油发电机组低载运行的危害性,给柴油发电机组配置了假负载,并设计了假负载自动控制系统;该假负载自动控制系统无需人工参与,能自动监测机组带载功率,并自动投入/切除假负载,有效地杜绝了机组发生低载运行情况;该控制技术应用于柴油发电机组,既满足了用户随意带载的要求,又确保了柴油发电机组安全运行,极具实用价值。

Adaptive Nonlinear Optimal Compensation Control for Electro-hydraulic Load Simulator

Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear parameters, viz. the flow gain coefficient of servo valve and total factors of flow-pressure coefficient. Taking trace error of torque control system to zero as control object, this article designs the adaptive nonlinear optimal compensation control strategy, which regards torque control output of closed-loop controller converging to zero as the control target, to optimize torque tracking performance. Electro-hydraulic load simulator is a typical case of the torque system which is strongly coupled with a hydraulic positioning system. This article firstly builds and analyzes the mathematical models of hydraulic torque and positioning system, then designs an adaptive nonlinear optimal compensation controller, proves the validity of parameters estimation, and shows the comparison data among three control structures with various typical operating conditions, including proportion-integral-derivative (PID) controller only, the velocity synchronizing controller plus P1D controller and the proposed adaptive nonlinear optimal compensation controller plus PID controller. Experimental results show that systems' nonlinear parameters are estimated exactly using the proposed method, and the trace accuracy of the torque system is greatly enhanced by adaptive nonlinear optimal compensation control, and the torque servo system capability against sudden disturbance can be greatly improved.

A practical nonlinear robust control approach of electro-hydraulic load simulator

This paper studies a nonlinear robust control algorithm of the electro-hydraulic load simulator （EHLS）. The tracking performance of the EHLS is mainly limited by the actuator＇s motion disturbance, flow nonlinearity, and friction, etc. The developed controller is developed based on the nonlinear motion loading model. The problems of the actuator＇s disturbance and flow nonlinearity are considered. To address the friction problem, the friction model of the loading motor is identified experimentally. The friction disturbance is compensated using the obtained friction model. Therefore, this paper considers the main three factors comprehensively. The developed algorithm is easy to apply since the controller can be obtained just with one step back-stepping design. The stability of the developed algorithm is proven via Lyapunov analysis. Both co-simulation and experiments are performed to verify the effectiveness of this method.

Adaptive Predictive Inverse Control of Offshore Jacket Platform Based on Rough Neural Network

The offshore jacket platform is a complex and time-varying nonlinear system, which can be excited of harmful vibration by external loads. It is difficult to obtain an ideal control performance for passive control methods or traditional active control methods based on accurate mathematic model. In this paper, an adaptive inverse control method is proposed on the basis of novel rough neural networks （RNN） to control the harmful vibration of the offshore jacket platform, and the offshore jacket platform model is established by dynamic stiffness matrix （DSM） method. Benefited from the nonlinear processing ability of the neural networks and data interpretation ability of the rough set theory, RNN is utilized to identify the predictive inverse model of the offshore jacket platform system. Then the identified model is used as the adaptive predictive inverse controller to control the harmful vibration caused by wave and wind loads, and to deal with the delay problem caused by signal transmission in the control process. The numerical results show that the constructed novel RNN has advantages such as clear structure, fast training speed and strong error-tolerance ability, and the proposed method based on RNN can effectively control the harmful vibration of the offshore jacket platform.

Robust Control for Static Loading of Electro-hydraulic Load Simulator with Friction Compensation

Load simulator is a key test equipment for aircraft actuation systems in hardware-in-the-loop-simulation. Static loading is an essential function of the load simulator and widely used in the static/dynamic stiffness test of aircraft actuation systems. The tracking performance of the static loading is studied in this paper. Firstly, the nonlinear mathematical models of the hydraulic load simulator are derived, and the feedback linearization method is employed to construct a feed-forward controller to improve the force tracking performance. Considering the effect of the friction, a LuGre model based friction compensation is synthesized, in which the unmeasurable state is estimated by a dual state observer via a controlled learning mechanism to guarantee that the estimation is bounded. The modeling errors are attenuated by a well-designed robust controller with a control accuracy measured by a design parameter. Employing the dual state observer is to capture the different effects of the unmeasured state and hence can improve the friction compensation accuracy. The tracking performance is summarized by a derived theorem. Experimental results are also obtained to verify the high performance nature of the proposed control strategy.

An experimental study of the dual-loop control of electro-hydraulic load simulator (EHLS)

This paper investigates motion coupling disturbance（the so called surplus torque）in the hardware-in-the-loop（HIL）experiments.The＇＇velocity synchronization scheme＇＇was proposed by Jiao for an electro-hydraulic load simulator（EHLS）in 2004.In some situations,however,the scheme is limited in the implementation for certain reasons,as is the case when the actuator＇s valve signal is not available or it is seriously polluted by noise.To solve these problems,a＇＇dual-loop scheme＇＇is developed for EHLS.The dual-loop scheme is a combination of a torque loop and a position synchronization loop.The role of the position synchronization loop is to decouple the motion disturbance caused by the actuator system.To verify the feasibility and effectiveness of the proposed scheme,extensive simulations are performed using AMESim.Then,the performance of the developed method is validated by experiments.

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.

空调负荷参与电力系统调频的温度设定值概率控制策略

作为一类重要的需求响应资源,空调负荷能够实时调节有功负荷进而参与电力系统调频。传统温度设定值控制方式假设空调的温度设定值连续可调,而忽略了空调的最小温度调节步长(MSoTA)。针对绝大多数空调MSoTA为1℃,提出一种基于温度设定值调节概率(TSPAP)的空调负荷控制策略,使得空调负荷集群的聚合功率连续可调,以更好地参与电力系统调频。所提出的方法采用双层广播控制的框架,将空调负荷划分为6种独立的状态,并根据不同的状态将功率调节需求调制成TSPAP。TSPAP作为全局控制信号下发给各个分散控制器,并被解调为±1℃的温度设定值调节信号,下发给各个空调。仿真结果表明,该方法能够在单个空调MSoTA为1℃的情况下,实现对大量空调负荷聚合功率的连续调节,从而在一次调频和二次调频中获得更好的效果。

永磁同步电机新型有限集模型预测速度控制

为了保证传统有限集模型预测速度控制中速度采样频率和控制周期一致,使用预测-校正方法进行反馈速度的测量,并结合卡尔曼滤波器进行负载观测,根据控制周期合理安排速度和负载观测的时序。针对传统有限集模型预测速度控制的稳态误差和较大转矩脉动问题,提出一种比例-积分-微分型代价函数,其中积分项用于消除稳态误差,微分项用于抑制转矩脉动。仿真和实验结果表明,所提出的新型有限集模型预测速度控制方法和传统有限集模型预测速度控制方法相比,在稳态时具有更小的稳态误差和转矩脉动,相电流总谐波失真(THD)从65.35%减小到了21.54%;和传统有限集模型预测电流控制方法相比,在起动、加减速和负载突变时的响应速度均加快了0.2~0.5 s,具有更快的动态响应。

Study on Friction Torque Loading with an Electro-hydraulic Load Simulator

This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraulic load simulator. As the general Stribeck friction model has little related to static friction, it proposes a ＂torque-zero velocity＂ switcher, in which a zero-velocity controller is developed to load the static friction and a torque controller the kinetic friction. With the help of mathematical modeling, this article designs a ＂torque-zero velocity＂ switching controller and, correspondingly, provides a ＂dual-threshold judgment＂ algorithm. Simulation results indicate that the proposed method can be successfully used to carry out the static and kinetic friction simulation with an electro-hydraulic load simulator.

基于模糊神经网络的水轮发电机组甩负荷过程调速器开度模式控制

基于模糊神经网络的水轮发电机组甩负荷过程调速器开度模式控制方法,能够快速稳定甩负荷过程中水轮发电机组的运行频率,保障电力系统平稳运行。构建水轮发电机组调速器数学模型,以模型中3个关键调节系数为目标输出,发电机组转速的误差变化率与误差为目标输入,设计5层模糊神经网络模型与控制规则;通过该模型依据此控制规则,模糊推理与模糊化目标输入,并持续迭代学习训练后,输出3个关键调节系数,向PID控制器内输入此类系数;由PID控制器以此输入为依据,控制水轮发电机组甩负荷过程调速器的开度模式,获得稳定频率输出。结果显示,该方法可通过对实验水轮发电机组甩不同额度负荷过程中调速器开度模式的控制,有效调整并稳定不同甩负荷过程中机组的运行频率,且控制中的控制精度较高,调整用时与超调量均较低,综合控制效果理想。

数据中心灾后排风机配电设计详解

根据数据中心灾后排风机的特殊性,探讨灾后排风机的由来和设置、配电系统设计、配电箱安装位置、导线选择、防火阀设置和设计深度。论述数据中心单机房、多机房状况下,不同功能灾后排风机的配电设计原则和控制系统方式。

海洋潮流能发电机组控制系统开发

海洋潮流能是一种清洁的可再生能源,开发海洋潮流能对缓解能源和环境问题具有重要的意义。潮流能发电机组控制系统是潮流能发电的关键技术之一。文中介绍了潮流能发电机组控制系统的组成和采取的核心控制技术。从硬件电路设计和软件程序开发2个方面详细说明了潮流能发电机组控制系统中蓄电池充放电控制、能耗负载控制和自动变桨距控制的原理。实验结果表明所开发的控制系统能够保证发电系统可靠、安全、稳定地运行。

基于温度密度聚类的热泵负荷集群控制策略

首先描述了典型温控负荷的热力学模型,并在此基础上讨论了常用温度设定控制策略下负荷温度分布变化及负荷开关状态变化。随后以温度队列为基础,提出了一种基于负荷温度的密度聚类集群控制策略。该策略考虑负荷在温度区间内的分布情况,通过密度聚类算法对负荷群进行聚类分析并确定密集区域与非密集区域;随后计算温度节点和补偿节点并确定设备响应群体和温度设定值;最后以温度设定值为响应信号对负荷群进行控制。以常用温控负荷电热泵为控制对象进行仿真分析,与常用温度设定控制下负荷群开关变化次数进行了对比。结果显示,负荷在控制中开关状态变化次数明显降低,负荷群中发生开关状态变化的负荷数目明显减少。

知觉负载、注意定势与选择性注意

本研究采用Eriksen Flanker(侧抑制)范式,将当前任务区分为高、低知觉负载两种条件,并系统操纵边缘视野干扰项与中央靶子的不同加工层次关系,从而考察注意选择的知觉负载理论。实验一发现,高知觉负载情况下没有任何flanker冲突效应,而低知觉负载情况下既有知觉层次和反应层次的冲突效应,也有一致条件下的促进效应。实验二增加了一致条件试次的比例,从而操纵自上而下的注意定势,发现高、低知觉负载情况下都存在知觉冲突效应和一致条件下的促进效应。这些发现表明,对任务无关信息的加工既受到任务相关信息的知觉负载和剩余加工资源的分配的影响,也受到自上而下注意定势的影响;自下而上和自上而下过程相互作用,共同决定加工资源的分配和注意选择的认知阶段。

基于对角递归神经网络整定的PID解耦单元机组负荷控制系统

针对火电厂单元机组具有多变量强耦合、非线性及参数时变的受控对象,提出了基于对角递归神经网络整定的PID解耦控制方法,其主要特点是能够提供一个对角递归神经网络来辩识系统模型,进而对PID控制器参数进行整定,实现多变量解耦控制。通过对火电机组负荷控制系统的设计和仿真研究,表明系统达到了动态近似解耦、静态完全解耦和无静差跟踪,并具有响应速度快,鲁棒性好等特点。