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.

Aircraft Electric Anti-skid Braking System Based on Fuzzy-PID Controller with Parameter Self-adjustment Feature

The principle of electric braking system is analyzed and an anti-skid braking system based on the slip rate control is proposed.The fuzzy-PID controller with parameter self-adjustment feature is designed for the anti-skid braking system.The dynamic model of aircraft ground braking is established in the simulation environment of MATLAB/SIMULINK,and simulation results of dry runway and wet runway are presented.The results show that the fuzzy-PID controller with parameter self-adjustment feature for the electric anti-skid braking system keeps working in the state of stability and the brake efficiencies are increased to 93%on dry runway and 82%on wet runway respectively.

Design Method for the Magnetic Bearing Control System with Fuzzy-PID Approach

The five degree freedom magnetic bearing is researched and its structure and working principles are introduced also. Based on the fuzzy control technology, combining fuzzy algorithm and PID control method, identifying the transition process mode of the online system to get the PID parameters＇ self-adjusting, the magnetic beating system＇s Fuzzy-PID nonlinear controller is designed by analyzing the system control demands. The Fuzzy-PID nonlinear controller can deal with the magnetic bearing system＇ s open loop instability and strong nonlinearity, and the approach could improve the system＇s rapidity, adaptability, stability and dynamic characteristics. Comparative analysis and experiments are conducted between linear PID and nonlinear fuzzy- PID control methods, the results show that the fuzzy-PID controller is better, and the five-freedom magnetic bearing＇ s rotary precision experiments are conducted by the fuzzy-PID controller, it satisfies the control rotary precision demands and realizes the hearing＇s steady floating and rotating.

Performance analysis of semi-active cab’s hydraulic system of the vibratory roller using optimal fuzzy-PID control

In order to evaluate the performance of semi-active cab’s hydraulic mounts(SHM)of the off-road vibratory roller with the optimal fuzzy-PID(proportional integral derivative)control,a nonlinear dynamic model of the vehicle interacting with off-road terrains is established based on Matlab/Simulink software.The weighted root-mean-square(RMS)acceleration responses of the driver’s seat heave and the cab’s pitch angle are chosen as objective functions.The SHM is then optimized and analyzed via the optimal fuzzy-PID control under different operation conditions.The simulations results show that the driver’s ride comfort and the cab shaking are greatly affected by the off-road terrains under various operating conditions of the vehicle,especially at the speed from 8 to 12 km/h on a very poor terrain surface of Grenville soil ground under the vehicle travelling.With SHM using the optimal fuzzy-PID control,the driver’s ride comfort and the cab shaking are clearly improved under various operation conditions of the vehicle,particularly at the speed from 6 to 7 km/h of the vehicle traveling.

Implementation of Fuzzy-PID in Smart Car Control

An unmanued smart car control system and the fuzzy-PID control algorithm are produced.A design scheme of fuzzy-PID controller is put forward.The simulation analysis from matlab indicated that the dynamic performance of fuzzy-PID control algorithm is better than that of usual PID.Experimental result of smart car show that it can follow the black guid line well and fast-stable complete running the whole trip.

A New Coordinated Fuzzy-PID Controller for Power System Considering Electric Vehicles

With penetration growing of renewable energy sources which integrated into power system have caused problems on grid stability. Electric Vehicles (EV) are one of the renewable energy sources that can bring significant impacts to power system during their charging and discharging operations. This article established a model of single machine infinite bus (SMIB) power system considering EV as a case study of load disturbance for power system oscillation. The objective of this research is to enhance stability and overcome the drawbacks of traditional control algorithms such as power system stabilizer (PSS), PID controller and fuzzy logic controller (FLC). The implementation’s effect of FLC parallel with PID controller (Fuzzy-PID) has been shown in this paper. The speed deviation (?ω) and electrical power (Pe) are the important factors to be taken into consideration without EV (only change in mechanical torque), EV with change in the mechanical torque and sudden plug-in EV. The obtained result by nonlinear simulation using Matlab/Simulink of a SMIB power system with EV has shown the effectiveness of using (Fuzzy-PID) against all disturbances.

矿井主通风机不停风倒机控制的研究与实现

为解决传统矿井通风系统“停机倒机”方式存在的通风机启动风阻大且停机切换过程中易引起较大风量波动及瓦斯积聚等问题,提出了一种基于模糊PID控制的矿井主通风机不停风倒机控制策略,并以PLC为控制核心、工业以太网为通信网络对控制系统进行设计,系统通过对垂直、水平风门开合角度的远程智能控制保持倒机过程风量恒定,有效提高了风机倒机过程的稳定性。

调度集中系统与计算机联锁系统通信接口故障案例分析

调度集中系统(CTC)与计算机联锁系统通信良好、信息交互完整,是车站有序办理行车作业的安全基础和效率保证。为提高EI32-JD计算机联锁系统的稳定性,降低因计算机联锁系统导致CTC控制台显示异常的故障率,通过分析典型的故障案例,提出对应的改进措施。首先,在完善联锁软件逻辑方面,采用优化操作机和联锁机倒机参数的方法,解决因计算机联锁系统单系设备故障造成CTC控制台信息异常的问题;其次,在完善联锁硬件设计方面,对具有远端操控方式的计算机联锁系统提出2种优化方案,即将本地端冷备操作机升级为热备,或将本地CTC和远端操作机通信连接的串口光电转换器由2套升级为4套;最后,通过优化运维管理措施规范现场设备的日常维护和管理。经现场测试,提出的改进措施应用效果良好,有效提高了计算机联锁系统与CTC系统的通信质量,可为同类型设备故障处理提供参考。

A Mode-Switching Motion Control System for Reactive Interaction and Surface Following Using Industrial Robots

This work proposes a sensor-based control system for fully automated object detection and exploration(surface following) with a redundant industrial robot. The control system utilizes both offline and online trajectory planning for reactive interaction with objects of different shapes and color using RGBD vision and proximity/contact sensors feedback where no prior knowledge of the objects is available. The RGB-D sensor is used to collect raw 3D information of the environment. The data is then processed to segment an object of interest in the scene. In order to completely explore the object, a coverage path planning technique is proposed using a dynamic 3D occupancy grid method to generate a primary(offline) trajectory. However, RGB-D sensors are very sensitive to lighting and provide only limited accuracy on the depth measurements. Therefore, the coverage path planning is then further assisted by a real-time adaptive path planning using a fuzzy self-tuning proportional integral derivative(PID)controller. The latter allows the robot to dynamically update the 3D model by a specially designed instrumented compliant wrist and adapt to the surfaces it approaches or touches. A modeswitching scheme is also proposed to efficiently integrate and smoothly switch between the interaction modes under certain conditions. Experimental results using a CRS-F3 manipulator equipped with a custom-built compliant wrist demonstrate the feasibility and performance of the proposed method.

Application of Fuzzy Logic Controller to Level Control of Twin-Roll Strip Casting

An intelligent fuzzy-PID controller consisting of fuzzy logic controller and PID controller was developed to control the molten steel level of twin-roll strip caster.Additionally,a feedforward differential PID controller was used for stopper position control in order to avoid differential kick.It is proved by simulation that the proposed intelligent controller is able to obtain zero steady state error asymptotically and the control system is robust due to its fuggy behavior of the controller.

THEORETICAL AND EXPERIMENTAL STUDY ON THE PRESSURE AND VACUUM CONTINUOUS CONTROL SYSTEM BASED ON HYBRID PUMP

A novel pressure and vacuum continuous control system, which adopts a hybrid pump as pressure and vacuum source, is presented. The mathematical model of the system is developed. The theoretical simulation and analysis on the system are implemented in order to study the relationships among the characteristics, parameters and working points of the system. The experimental investigations on the system characteristics are presented with the adoption ofa fuzzy-PID controller. The simulation and experimental results indicate that the pressure and vacuum continuous control system based on hybrid pump has good dynamic and static performance, strong robustness and satisfactory adaptability to various system parameters. According to the results, system can successfully gain high accuracy and fast response signal. Also, the mathematical model of system is also testified by the experimental results.

Position Control of Single Pneumatic Muscle Actuator

The PID, fuzzy, self-organized fuzzy and self-organized fuzzy-PID controllers are adopted in the position control of single pneumatic muscle actuator. Experiments show that the self-organized fuzzy-PID is obviously effective for the position control of single pneumatic muscle actuator, which can realize precision within 0.3 mm and withstand 18?N variable load plus about 36?N fixed load. It is relatively precise and robust.

Measurement and AFPS control of molten steel level in strip casting

The measurement and control of the molten steel level are studied, which affect the quality of strip surface in strip casting. A system of molten steel measurement with a CCD (Charge Coupled Devices) sensor is designed, real-time measured data are given and its precision is analyzed. The level fluctuation model is derived, and an adaptive fuzzy-PID controller with supervisory control (AFPS) is proposed. The stability of the system is proved using Lyapunov theorem, and the simulation results are given when the model, the casting speed and the roll gap change. It is suggested that this kind of coupled nonlinear and time varying system is stable and robust using the designed AFPS controller.

无人值守泵房中基于ControlLogix的PLC双CPU硬冗余控制系统的应用

PLC控制系统是无人值守泵房稳定可靠运行的关键所在。为进一步保障无人值守泵房的安全供水,单CPU型的PLC控制系统已经无法满足安全供水的要求。因此,明确了双CPU硬冗余控制系统的改造,避免因PLC控制系统发生故障而使得机泵停止的情况发生。改造后,即使PLC发生故障,会自动冗余切换,有效保障计算机远程控制系统对所有机泵和辅机的正常操作,保障安全供水。重点介绍了双CPU硬冗余控制系统的原理、结构和无扰动切换过程,以及该系统在无人值守泵房中的成功应用。实践表明,双CPU硬冗余控制系统具有更高的可靠性和可用性,可以满足高可靠性工业控制的要求。

Wind Turbine Speed Compound Control of a New-Type Wind-Electric Hybrid Power Pumping Unit

Because the load of the oil beam pumping unit driven by pure electric motor changes sharply during operation,the power of the driving motor does not match and the energy efficiency is low.In this paper,a new type of wind-driven hydro-motor hybrid power system is proposed.The motor and the hydraulic motor are jointly driven,and the energy is recovered by a hydraulic pump with controllable displacement,so that the speed of the driving motor is relatively stable.In order to control the fan speed and keep up with the drastic changes of the outside wind speed,a control strategy of hybrid power system based on wind speed feed-forward compensation is proposed.Through simulation and experimental results,the following conclusions can be drawn:to begin with,the mathematic model is proved to be effective;next,simulation studies show that the proposed feed-forward control method can improve the response rate as well as reduce the response lag.This research can be a reference for the application of the feed-forward control method on the hybrid power system of beam pumping unit.system.

矿井主要通风机切换过程供给风量优化控制研究

矿井主要通风机切换过程中存在供给风量大范围波动甚至中断问题,易导致瓦斯浓度超限。常用的基于模型的主要通风机切换控制方法难以很好地对约束进行处理,基于智能算法的控制方法依赖专家知识和经验,具有主观性和随意性。针对上述问题,以中国平煤能源化工集团有限责任公司二矿主要通风机切换过程为研究背景,研究了主要通风机切换过程供给风量优化控制问题。基于流体动力学方程和图论概念,建立了主要通风机切换过程动态模型,并采用泰勒展开式对其进行线性化处理,以降低计算复杂度。考虑矿井主要通风机切换过程具有强非线性、系统状态受约束,且为离散的多输入多输出系统,采用模型预测控制(MPC)算法研究风量控制问题,设计了主要通风机切换过程MPC系统,将风量优化转换为二次规划问题。采用原对偶神经网络在线求解优化问题,实现主要通风机切换过程的供给风量实时优化控制。试验结果表明:MPC系统可有效实现主要通风机切换,切换过程中4个风门风量可很好地跟踪参考值;各采样时刻运算时间为0.027 s,满足切换过程实时性要求;供给风量波动最大值仅为0.9%,明显优于传统PID控制效果。

基于下垂控制的微电网孤岛-并网平滑切换策略

微电网在并网模式与孤岛模式间切换运行时会产生较大的暂态振荡。为实现在两种运行模式间的平滑切换,分析了微电网在两种模式运行时采用的不同控制方法,设计了一种基于下垂控制的平滑切换策略。在MATLAB/Simulink平台上搭建了微电网模型。试验结果表明,所提策略能够把系统模式切换时出现的暂态振荡限制在合理范围内,有效减小了并网点处电压、电流和频率的波动,取得了较好的孤岛-并网双向平滑切换效果。

储能系统离并网无缝切换控制策略研究

随着传统能源的日益枯竭,太阳能、风能、潮汐能等可再生能源正迅速发展,但新能源发电存在间歇性的问题,为了确保新能源发电的可持续性和稳定性,储能系统发挥着至关重要的作用。然而,采用传统控制方法,储能系统在离并网切换过程中,切换速度慢,会造成过流冲击,影响系统运行安全。为了解决离并网切换过程中的过流冲击问题,提出了一种基于PQ/VSG控制的储能系统离并网无缝切换控制策略,利用锁相环技术和预同步控制技术,实现储能系统离并网过程的平滑过渡,从而保证电力系统的稳定性。最后,通过仿真验证了基于PQ/VSG的储能系统离并网无缝切换控制策略的有效性。

轨道交通信号控制系统主备双系工作状态的识别与控制

目的:针对轨道交通信号控制系统冗余结构中主备双系状态切换时可能存在的风险,提出一种新的硬件判决方式以避免该风险。方法:轨道交通信号控制系统多采用二乘二取二和双机热备冗余结构,由2个功能完成相同的主备双系组成。主备双系各自有主控、同步和离线等3种固定的工作状态,其不允许同时出现为主控状态。这3种工作状态的控制与转换依赖于自身和对方系的工作状态。目前,系统工作状态的判决机制主要有通信判决和硬件判决2种方式。若采用通信判决,一旦通信出现问题,则存在同时出现主备双系都为主控状态的风险。为此,提出采用设置工作继电器的硬件判决方法,即通过继电器硬件判决方式来识别和控制系统主备双系的工作状态,以避免同时出现主备双系处于主控状态的风险。主备双系各设置一个工作继电器,通过继电器的硬件接点条件来反映对应系的工作状态,并提出了设计原理、判决原则、判决实现流程及应用环境,分析了硬件判决方式比通信判决方式具有的技术优势。结果及结论:通过采集工作继电器位置反映对应铁路信号控制系统各系的工作状态,主要有以下优势:①不依赖于主备双系间通信的状态,解决了由于通信问题带来状态信息丢失的问题;②不论系统是否开机,系间是否通信正常,各系都能通过采集对方工作继电器接点条件来识别对方系的工作状态,从而能准确控制本系的工作状态;③继电器反应速度明显高于通信处理的反应速度,一旦系统工作状态发生变化,工作继电器快速动作可使主备双系及时得到相应系的工作状态信息;④继电器具有固有失效安全特性,工作继电器一旦发生故障落下,使系统尽快转到离线状态;⑤通过继电器识别和控制系统工作状态,软件处理逻辑简单,也能使维护人员直观辨识系统工作状态。

微电网平滑切换控制方法及策略

微电网由并网运行模式到孤岛运行模式的平滑切换是保证微电网区域内重要负荷持续可靠供电的重要手段。文中利用MATLAB/Simulink仿真软件建立了逆变器微源类型的微电网模型,实现了微电网并网及孤岛2种运行模式及其相应的控制方法。在推导控制器系统传递函数的基础上,分析了控制参数对系统频谱特性的影响,并通过时域仿真研究了控制参数对微电网运行模式切换暂态过程的影响规律,在此基础上提出了基于控制器状态跟随的微电网平滑切换控制方法。同时,从微电源容量与微电网内负荷匹配程度的角度,提出了3区域平滑切换控制策略,有效地减小了微电网2种运行模式切换过程中的暂态振荡。通过仿真验证了所提出的平滑切换控制方法及策略的有效性。