无刷直流电机双闭环模糊自适应控制方法研究

在分析无刷直流电机数学模型的基础上,提出了一种双闭环模糊自适应控制方法。该控制系统是以电流环作为内环,采用传统的PI控制;转速环作为外环,采用PI控制与模糊控制相结合的方法,即模糊自适应控制方法。以速度误差及速度误差变化率作为模糊控制器的输入,大偏差时采用模糊控制,以增强系统的响应速度和鲁棒性;小偏差时采用传统的PI控制,使系统稳态无误差。仿真实验结果表明,相比于传统的PI控制系统,模糊双闭环自适应控制系统具有良好的动、静态特性,以及较强的鲁棒性。     

基于积分自整定模糊矢量控制系统研究

为提高采用PI转速调节器矢量控制调速系统的动静态性能,提出以积分自整定模糊控制作为矢量控制转速调节器,此调节器的比例系数不变,可根据转速偏差和偏差变化率来动态调节积分系数.在此基础上,建立了异步电机矢量控制模型.仿真结果表明:相对于采用PI转速调节器的矢量控制系统,积分自整定模糊矢量控制系统转速超调量小、调节时间短,可快速消除负载扰动引起转速偏差.     

采用模糊控制系统实现竖炉的自动化操作

在竖炉熔铜中应用模糊逻辑控制系统,可实现工艺过程的自动化,确保了保温炉中铜熔体储量的恒定,以及均一地控制竖炉出口处熔体的温度。这种模糊逻辑控制是以熔体基准输入和实际储存之间的偏差和偏差梯度作为模糊控制器的输入,以燃烧水平梯度为输出,通过建立燃烧水平与空气比率的关系来实现的。为防止炉子出口和燃烧器阻塞,分别采用了全天制图像判读监测技术以及新的浇铸机自动水平控制方法。     

基于特征参数的CO2弧焊电源的实时监测与评价

对CO2焊接短路过渡过程进行准确测量和综合分析,是控制和稳定焊接过程,保证焊接质量的前提,也是研究焊接过程和进行焊接试验必不可少的工具.本文研制了一种用于CO2弧焊电源工作过程的监测评价系统,该系统通过对弧焊规范参数和熔滴短路过渡过程特征参数的实时检测、分析以及综合评判,实现对CO2弧焊电源工作过程的监测与评价.     

模糊自适应控制在超临界660MW机组给水控制中的应用

以轩岗电厂一期超临界2×660 MW机组为例,对协调控制系统中给水控制系统的给水泵出力与液力耦合器出力不匹配造成的给水流量波动进行了分析和改进,提出了基于模糊自适应PID的给水控制策略,即应用模糊推理建立PID的比例系数(Kp)、积分系数(Ki)、微分系数(Kd)与给水流量偏差e及其偏差变化率△e之间的模糊关系,根据不同的e和△e在线调整Kp、Ki、Kd.给水控制系统改进后,使被控对象具有良好的动、静态特性及鲁棒性,给水流量稳定,能够满足机组负荷变化的要求.     

变极性脉冲MIG焊双逆变弧焊电源

提出采用大功率IGBT设计变极性脉冲MIG焊双逆变弧焊电源。弧焊电源由一次逆变电路、二次逆变电路等构成,双逆变弧焊电源由80C196KC单片机控制。一次逆变整流输出正极性端和负极性端,双极性输出端的电压电流静态特性与动态特性完全相同;二次逆变电路由2只IGBT构成,二次逆变输出变极性电流电压给MIG焊接电弧提供能量。单片机协调控制变极性脉冲MIG焊的脉冲电流及电弧极性、电弧电压及熔滴过渡频率,实现了稳定的焊接过程。     

异步电动机三闭环模糊PI矢量控制方法研究

针对异步电动机矢量控制因电动机参数和负载变化使其性能变差的问题,设计了转矩环、磁链环、转速环三闭环模糊PI矢量控制系统。以速度误差和速度误差变化率作为模糊控制器的输入,大偏差时采用模糊控制,小偏差时采用PI控制。仿真结果表明,相比于传统的矢量控制系统,三闭环模糊PI矢量控制系统具有良好的动、静态性能以及较强的鲁棒性。     

基于特征参数的CO2弧焊电源的实时监测与评价

对CO2 焊接短路过渡过程进行准确测量和综合分析 ,是控制和稳定焊接过程 ,保证焊接质量的前提 ,也是研究焊接过程和进行焊接试验必不可少的工具。本文研制了一种用于CO2弧焊电源工作过程的监测评价系统 ,该系统通过对弧焊规范参数和熔滴短路过渡过程特征参数的实时检测、分析以及综合评判 ,实现对CO2 弧焊电源工作过程的监测与评价。     

基于控制历史的过热汽温模糊串级控制

针对过热汽温对象具有大迟延、不确定等特点,设计出了一种基于控制历史的串级控制系统.在对控制对象的动态特性分析的基础上,用历史的控制信息代替偏差变化率作为模糊控制的决策依据,从而及时地反映出被控制量的变化趋势;并在此基础上,引入了比例环节,综合了PID控制器和模糊控制器的优点,克服了传统模糊控制器结构上的缺陷.通过仿真实验,将用该控制器构成的汽温串级控制系统的控制效果与常规PD及传统模糊控制作比较,证明了所提出的控制方案能够有效减小延迟时间对控制效果的影响,具有较强的适应性.     

模糊自适应PID楼宇变频恒压供水控制系统设计

针对楼宇变频恒压供水控制系统工作时被控对象参数会发生变化,同时整个系统是一个复杂、大滞后时延系统.传统的控制方法大多采用PID进行控制,但是其控制效果差.为了对楼宇中供水系统中的水压进行有效的控制,采用模糊自适应PID控制器根据楼宇中供水管网的水压偏差和偏差变化率对PID参数进行自动调整,并经过MATLAB仿真.结果表明,模糊自适应PID与PID相比,具有更好的稳态精度和动态响应,满足楼宇变频恒压供水系统的控制要求.     

Application of fuzzy logic to spatial thermal control in fusion welding

This paper considers the problem of sensing and controlling torch position in the pulsed gas metal arc welding (P-GMAW) process. The attitude and positional control described is essential to the production of quality welds with a specified geometry. For constant current arc welding processes, as normally employed with P-GMAW, the arc voltage signal variations that occur as a function of changes in the contact-tube-to-work distance can be used to automatically control the welding system with respect to bead placement and proper sidewall fusion. However, the arc voltage signals are uncertain and noisy because of many inherent disturbances associated with the electrode tip, droplet formation, droplet detachment, and droplet transfer through the arc. To deal with the nonlinear time-varying process with its inherent stochastic disturbances associated with the metal transfer, the theory of fuzzy sets was used as a general framework to interpret the uncertain arc signals and provide logic for control. The fuzzy logic controller weld joint tracking system was implemented and tested with pulsed gas metal arc welds under a variety of conditions. The goal was to obtain quick and accurate response to tracking errors in the presence of disturbances. A series of experiments was conducted to evaluate the performance of the fuzzy logic controller. The experimental results show that the fuzzy logic controller was found to be suitable for these purposes and better than methods based on signal averaging and bipolar decision levels under these criteria.     

基于模糊PID控制的望远镜伺服控制系统

为了满足某种望远镜传递函数时变、速度精度要求高、位置定点时间长的控制要求,在分析经典PID的基础上,提出了一种模糊控制方案。通过构造模糊控制规则,模糊PID控制器能够根据误差和误差变化对控制器的比例、积分增益进行实时的调整。针对某望远镜模型,仿真验证了模糊PID控制与经典PID的控制性能,并在该望远镜上实验验证了速度控制及位置定点实验,速度为138.8°/s时最大稳态误差为0.4°/s,位置定点最大误差为0.0002°。仿真结果和实验结果均表明:模糊PID控制能满足该望远镜的观测要求。     

铁罐电阻焊机自学习模糊控制系统的设计

本文介绍电阻焊机的一种自学习模糊控制器的设计。系统实现机器较复杂的机械动作的同时，利用带PCL-818HD多功能卡的工业PC实现焊接电流的高速采样与控制，实现较高精度的恒电流控制，保证焊接的质量。焊接电流的控制采用自学习模糊控制算法。     

一种基于模糊神经网络的电弧控制系统

等速送丝系统中电弧的控制是一个极为重要的环节,其控制质量的好坏直接影响到焊接过程的稳定。本文研究了一种模糊神经网络控制器,该控制器根据给定电压与反馈电压的误差和误差变化率,能够自动调整隶属函数和控制规则,具有自学习和自适应能力。     

CO_2弧焊熔滴过渡过程焊接电弧的并联式波形控制

提出并实现了一种新型的并联式电弧波形控制法 ,设计了相应的IGBT波形控制器 ,该法可用于CO2 弧焊熔滴过渡过程电弧的波形控制。对焊接电弧参数实时采样以及工艺试验表明 ,所研制的波控器对减少金属飞溅和改善焊缝成型均有明显效果     

磁控开关型故障限流器偏置电流模糊PID控制

为提高偏置电流系统的控制精度,设计了一种运用模糊PID在线修改控制器参数的新型偏置电流控制系统。该系统集PID控制及模糊控制的优点于一体,具有不需要精确的数学模型就能够快速、精确控制偏置电流的特点。试验证明,利用该控制系统对限流器偏置电流进行控制,限流器的响应速度和限流效果可以得到保证。     

Load frequency control using power demand estimation and fuzzy control

Numerous control methods based on modern control theory have been proposed to improve the load frequency control (LFC) characteristics of power systems. These control methods generally regard the load frequency control system as a linear system model. Furthermore, complicated mathematical equations have to be solved to determine control laws. However, realistic power systems are nonlinear, i.e., the nonlinearities of tie-lines connecting between the control areas and of generation rate constraints of power plants exist. Consequently, it is considered that the design of controllers is difficult. In this paper, the application of fuzzy control to the load frequency control system is proposed to solve the forementioned problems. The proposed control first, to satisfy the load frequency control requirements, estimates power demand variations of the control areas and uses them as the output set-point values of power plants, instead of using an integral-type controller. Next, to improve stability and optimality of the nonlinear load frequency control system using the fore-mentioned output set-point control method, the proportional-type fuzzy control considering a computation time-delay is implemented. Parameters of the proposed fuzzy controller are determined by minimizing the integral square of the area control error (ACE) to ensure optimality of the system.     

A fuzzy logic controlled superconducting magnetic energy storage,SMES frequency stabilizer

This paper presents application of fuzzy logic controlled superconducting magnetic energy storage device, SMES to damp the frequency oscillations of interconnected two-area power systems due to load excursions. The system frequency oscillations appear due to load disturbance. To stabilize the system frequency oscillations, the active power can be controlled via superconducting magnetic energy storage device, SMES. The error in the area control and its rate of change is used as controller input signals to the proposed fuzzy logic controller. In order to judge the effect of the proposed fuzzy logic controlled SMES, a comparative study is made between its effect and the effect of the conventional proportional plus integral (PI) controlled SMES. The studied system consists of two-area (thermal–thermal) power system each one equipped with SMES unit. The time simulation results indicate the superiority of the proposed fuzzy logic controlled SMES over the conventional PI SMES in damping the system oscillations and reach quickly to zero frequency deviation. The system is modeled and solved by using MATLAB software.     

A rule-based fuzzy logic controller for a PWM inverter in a standalone wind energy conversion scheme

The paper presents a rule-based fuzzy logic controller to control the output power of a pulse width modulated (PWM) inverter used in a stand-alone wind energy conversion scheme (SAWECS). The self-excited induction generator used in SAWECS has the inherent problem of fluctuations in the magnitude and frequency of its terminal voltage with changes in wind velocity and load. To overcome this drawback the variable magnitude, variable frequency voltage at the generator terminals is rectified and the DC power is transferred to the load through a PWM inverter. The objective is to track and extract maximum power from the wind energy system and transfer this power to the local isolated load, This is achieved by using the fuzzy logic controller which regulates the modulation index of the PWM inverter based on the input signals: the power error; and its rate of change. These input signals are fuzzified, that is defined by a set of linguistic labels characterized by their membership functions predefined for each class. Using a set of 49 rules which relate the fuzzified input signals to the fuzzy controller output, fuzzy set theory and associated fuzzy logic operations, the fuzzy controller's output is obtained. The fuzzy set describing the controller's output (in terms of linguistic labels) is defuzzified to obtain the actual analog (numerical) output signal which is then used to control the PWM inverter and ensure complete utilization of the available wind energy. The proposed rule-based fuzzy logic controller is simulated and the results are experimentally verified on a scaled down laboratory prototype of the SAWECS     

基于模糊控制的永磁同步电动机直接转矩控制

提出了一种基于模糊控制的永磁同步电机直接转矩控制系统。系统将定子磁链偏差、转矩偏差和定子磁链矢量的位置角模糊化并作为模糊控制器的输入量,根据所制定的模糊控制规则综合选择控制逆变器开关状态的电压矢量。并且,零电压矢量被引入以保证在一定的情况下保持当前的转矩和磁链状态,减少逆变器开关次数。仿真实验结果表明该系统能有效抑制转矩脉动,提高系统的起动响应速度。