多机驱动带式输送机功率平衡模糊控制方法

针对以调速型液力偶合器作为驱动装置的带式输送机多机驱动系统采用传统方法控制各驱动电动机之间的功率平衡,存在系统运行过程中动态特性较差、功率平衡调节精度较低等问题,提出一种多机驱动带式输送机功率平衡模糊控制方法:对液力偶合器涡轮转速实行闭环控制,保证在工作机负载发生变化时带式输送机具有恒定不变的带速;转速调节器采用模糊控制器代替传统的PID控制器,以提高功率平衡的调节精度。Matlab仿真结果表明,采用模糊控制方法可有效改善系统动态性能,提高功率平衡调节精度。     

多机驱动带式输送机功率平衡模糊控制方法

针对以调速型液力偶合器作为驱动装置的带式输送机多机驱动系统采用传统方法控制各驱动电动机之间的功率平衡,存在系统运行过程中动态特性较差、功率平衡调节精度较低等问题,提出一种多机驱动带式输送机功率平衡模糊控制方法:对液力偶合器涡轮转速实行闭环控制,保证在工作机负载发生变化时带式输送机具有恒定不变的带速;转速调节器采用模糊控制器代替传统的PID控制器,以提高功率平衡的调节精度。Matlab仿真结果表明,采用模糊控制方法可有效改善系统动态性能,提高功率平衡调节精度。     

物联网技术下带式输送机多机功率平衡控制

针对目前煤矿多电动机驱动带式输送机对多机功率平衡控制的需求,结合变频调速和物联网技术,提出了一种带式输送机多机功率平衡控制方法,研究了控制系统结构及控制原理。该方法采用变频器调节电动机转速,通过执行器/传感器节点检测电动机转速和定子转矩电流T轴分量,并将检测数据以无线通信方式传输给邻居节点;执行器/传感器节点基于电动机转速和定子转矩电流T轴分量的不一致性来构造控制输入,用于调节变频器给定转速,并通过转速微调实现电动机转速或转矩不一致情况下的多机功率平衡。试验结果验证了该方法可在负载不平衡和负载突变情况下实现多机功率平衡。     

多机驱动带式输送机功率平衡的研究与分析

对于多机驱动的带式输送机,为防止因电动机严重偏载而导致设备损坏,必须关注多机间的功率平衡问题。文章介绍了液体黏性传动装置的结构与工作原理及其液压伺服控制系统原理,给出了一种利用液体黏性传动装置实现带式输送机功率平衡调节的电流控制法原理,即通过改变液体黏性传动装置所配用的液压伺服控制系统中各个电液比例阀中电流的大小,使液体黏性传动装置中的控制油压改变以调节各电动机的负荷大小,从而改变电动机的电流,以使多台电动机功率趋于一致或相差在允许的范围内。实际应用表明,基于电流控制法对带式输送机进行功率平衡调节不仅能满足输送带的启动及功率平衡要求,还便于安装维护,经济适用。     

多机驱动带式输送机功率平衡控制方法

针对采用液体黏性软启动装置的多机驱动带式输送机在启动过程中各电动机功率不平衡的问题,提出了一种多机驱动带式输送机功率平衡控制方法:利用电流预测算法预测电动机电流,以提高控制响应速度;根据各电动机之间的预测电流偏差,通过比例微分控制算法调节液体黏性软启动装置所配用的控制泵给定频率,进而改变电动机电流,使各电动机电流差控制在一定范围内。现场应用结果表明,在带式输送机空载和重载启动时,该方法均能对电动机过大电流进行抑制调节,实现带式输送机平稳启动和功率平衡。     

基于Hamilton函数方法的多机多负荷电力系统分散励磁控制

采用Hamilton函数方法研究了多机多负荷电力系统的励磁控制问题. 首先, 通过预置状态反馈完成了系统的耗散Hamilton实现. 然后, 基于该耗散实现形式设计了非线性分散励磁控制器, 分析了闭环系统的稳定性. 该控制器能充分利用系统内在的功率平衡特性. 仿真结果验证了控制策略的有效性.     

基于有功功率修正的MMC串联结构微电网相间功率平衡控制策略

针对孤岛不平衡负载下模块化多电平变换器（MMC）串联结构微电网系统中微源输出功率波动,引起的相间功率不平衡及运行不稳定问题,研究了一种基于有功功率修正（Active Power Correction,APC）的相间功率平衡控制策略。基于系统孤岛模式等效电路,对系统输出功率进行了数学建模,并分析了相间功率流动模式。在三相输出电压对称的前提下,根据微源功率及负载功率确定需要修正的功率,设计了环流控制器,对直流环流控制实现相间功率互济。通过仿真验证,该策略能使相间功率自适应动态调节,达到相间功率平衡的目的。     

多机驱动大倾角带式输送机模糊控制算法

针对多电动机驱动的大倾角带式输送机重载启动与停止时物料下滑或滚动等问题,建立了多机驱动大倾角带式输送机模糊控制算法,介绍了大倾角带式输送机总体控制模型、带式输送机的速度设定算法和功率平衡模糊PID参数自整定算法。应用结果表明,该模糊控制算法能够根据煤流量的实时变化自动调节带式输送机的运行速度,速度控制误差小于2%,功率控制误差小于2.5%,能使4台驱动电动机功率趋于一致,实现了四机驱动带式输送机可靠、安全、节能运行。     

闭环控制微波理疗机的设计

介绍了一种基于PIC16F877高性能单片机控制的微波理疗机的设计及系统工作原理,提出了闭环反馈功率控制方案,并较为详细的阐述了系统数据采集、D/A转换、功率调节等硬件电路设计,同时还指出了软件实现的特点。该理疗机输出功率范围为30~150W,并具有数字显示,报警提示等功能。     

带式输送机多机变频驱动功率平衡控制研究

针对多机驱动带式输送机在负荷变化、加减速过程中极易出现因功率不平衡而造成电动机过载甚至损坏等问题,依据转矩分配原则推导出电动机转矩分配公式;采用变频驱动的主从控制方法,主机为速度、磁链闭环的矢量控制,从机为速度级联下的转矩控制,主、从机在转矩分配给定情况下进行转矩闭环控制;建立了功率平衡控制系统模型,并给出了双电动机拖动功率平衡控制系统结构。Matlab仿真结果表明,在负荷变化、加减速过程中各电动机输出转矩可实现按比例分配,证明了功率平衡控制系统的有效性。     

Power system stability enhancement by WAMS-based supplementary control of multi-terminal HVDC networks

This paper deals with supplementary control of a MTDC network designed for the stability enhancement of a AC power system. The proposed control is a WAMS-based control modulating the real and reactive power at the terminals of the DC network. Relevant control formulas have been derived for a linear multi-machine system model with the application of the direct Lyapunov method. Validity and robustness of the proposed control has been verified by computer simulation for a multi-machine test system using a nonlinear model and detailed modeling of power system components. The proposed control is robust and insensitive to changes in the network configuration and loading conditions in the AC power system. In the case, when more of the MTDC networks and/or the HVDC links are used in one interconnected power system the proposed stabilizing control produces additive damping i.e. each controlled network element contributes to the positive damping. Some practical aspects have also been discussed. The proposed WAMS-based stabilizing control of the MTDC network is innovative by both its main concept and the derivation of control formulas using the direct Lyapunov method.     

多机电力系统PSS参数优化新方法

机械回路谐振引起了励磁系统频率特性曲线出现“波峰”和“波谷”, 造成现有方法不易准确测量或计算励磁系统相位滞后角. 为此, 本文提出一种新的多机系统PSS参数优化方法. 首先, 重新定义基于多机模型的励磁系统相位滞后角, 并推导出相应的计算公式, 基于新定义的计算方法不再受机械回路谐振的影响, 可以得出更合理的计算结果.然后, 在PSS增益整定时, 将问题描述转化为多机系统部分输出量反馈的优化模型, 通过求解Levine-Athans方程组得到最佳PSS增益. 最后将所提方法应用于一个8机电力系统, 与传统方法比较后, 表明电力系统阻尼特性得到进一步改善.     

A heuristic training-based least squares support vector machines for power system stabilization by SMES

This paper presents the application of least squares support vector machines (LS-SVMs) to design of an adaptive damping controller for superconducting magnetic energy storage (SMES). To accelerate LS-SVMs training and testing, a large amount of training data set of a multi-machine power system is reduced by the measurement of similarity among samples. In addition, the redundant data in the training set can be significantly discarded. The LS-SVM for SMES controllers are trained using the optimal LS-SVM parameters optimized by a particle swarm optimization and the reduced data. The LS-SVM control signals can be adapted by various operating conditions and different disturbances. Simulation results in a two-area four-machine power system demonstrate that the proposed LS-SVM for SMES controller is robust to various disturbances under a wide range of operating conditions in comparison to the conventional SMES.     

A Nonlinear Coordinated Approach to Enhance the Transient Stability of Wind Energy-Based Power Systems

This paper proposes a novel framework that enables the simultaneous coordination of the controllers of doubly fed induction generators (DFIGs) and synchronous generators (SGs). The proposed coordination approach is based on the zero dynamics method aims at enhancing the transient stability of multi-machine power systems under a wide range of operating conditions. The proposed approach was implemented to the IEEE 39-bus power systems. Transient stability margin measured in terms of critical clearing time along with eigenvalue analysis and time domain simulations were considered in the performance assessment. The obtained results were also compared to those achieved using a conventional power system stabilizer/power oscillation (PSS/POD) technique and the interconnection and damping assignment passivity-based controller (IDA-PBC). The performance analysis confirmed the ability of the proposed approach to enhance damping and improve system’s transient stability margin under a wide range of operating conditions.      

A brand new nonlinear robust control design of SSSC for transient stability and damping improvement of multi-machine power systems via pseudo-generalized Hamiltonian theory

Nonlinear robust control of static synchronous series compensator (SSSC) is investigated in multi-machine multi-load power systems by using the pseudo-generalized Hamiltonian method. First, the uncertain nonlinear differential algebraic equation model is constructed for the power system. Then, the dissipative pseudo-generalized Hamiltonian realization of the system is established by means of variable transformation and prefeedback control. Finally, based on the obtained dissipative pseudo-generalized Hamiltonian realization, a brand new nonlinear robust controller is put forward. The proposed controller can effectively use the internal structure and the energy balance property of the power system. Simulation results demonstrate the effectiveness and robustness of the control scheme.     

具有扇形执行器的多机电力系统气门开度的时滞无关镇定

本文研究了具有扇形执行器的多机电力系统气门开度的时滞无关分散控制器和鲁棒分散控制器的设计问题.首先利用三角变换把非线性关联函数变换为子系统状态变量的二次有界不等式形式,然后基于Lyapunov稳定性理论,推导出闭环多机电力系统及其参数不确定系统渐近稳定的线性矩阵不等式(LMI)充分条件,最后以两机无穷大母线系统为例进行了仿真分析,验证了所提方法的有效性.     

互联非线性系统反馈主导控制设计方法及汽门开度控制应用

分析了电力系统非线性的数学性质,指出电力系统非线性是一种有界非线性.在此基础上,将反馈主导方法(feedback domination method,FDM)引入多机电力系统非线性控制.该方法与反馈线性化方法不同;反馈线性化方法是通过反馈将原非线性系统转化为线性系统,反馈主导方法则是通过反馈将原非线性系统转换为特定形式的非线性系统,该特定形式的非线性系统的动态由反馈引入的非线性部分主导.以多机系统非线性汽门控制问题为例,设计了反馈主导非线性汽门控制器,该控制器仅包含本地量测量,易于实现.数值仿真表明,多机系统反馈主导非线性汽门控制器可显著提高电力系统暂态稳定性.     

Non-linear decentralized saturated controller design for multi-machine power systems

A direct method of constructing a decentralized saturated controller is very important in the controller design of multimachine power systems. Among the existing designs the author first constructed a state feedback, then saturated the controller. However, the author could not prove that this saturated controller was valid. In this paper a multi-machine power system as a Hamiltonian control system with dissipation is first represented. Then using a Hamiltonian function a decentralized saturated excitation control scheme, which is a static measurable feedback, is proposed. Last, the design is discussed in detail on a three-machine power system. Simulations show that the saturated, simple control law works well.