基于BP神经网络的最优励磁控制器

设计了一种新型的基于BP神经网络的最优励磁控制器(NNOEC)。在线性最优励磁控制的基础上,利用4层BP神经网络对发电机的运行方式和系统所遭受的干扰类型进行辨识,通过对网络的训练,使得网络能够实时根据发电机的状态量来调节最优控制的反馈矩阵,以适应当前的运行点和所遭受的干扰。仿真结果表明,所设计的NNOEC在系统运行方式较大的变化范围内都能提供很好的控制性能,在大小扰动下均表现出很好的阻尼特性和良好的电压性能。     

基于在线辨识的实时最优励磁控制器

设计了一种在线实时最优励磁控制器（RTOEC）,其辨识器能够由发电机运行状态的变化采用非线性最小二乘法辨识法准确辨识出单机无穷大模型中的系统参数,从而可根据辨识结果及其系统所遭受的扰动,通过线性最优控制理论实时计算出线性最优励磁控制的反馈增益矩阵,以适应系统当前的运行点和所遭受的干扰。仿真结果表明,所设计的RTOEC能够适应系统运行状态的大范围变化,在大小扰动下均表现出良好的控制性能,有效提高了电力系统的静态和暂态稳定性。     

大型汽轮发电机励磁的自适应控制

本文提出了一种大型汽轮发电机励磁的自适应控制方案.该方案可以根据系统运行点的变化调整反馈增益矩阵,使系统保持设计点的动态品质.本文用数字计算机对自适应励磁控制器的效果进行了仿真研究,并与最优线性控制进行了比较.结果表明所设计的控制器能为系统提供良好的阻尼,显著地改善了系统的动态响应.动态品质及动态稳定性均优于基于二次型性能指标的最优控制.     

励磁与SMES协调控制中的静态偏移问题

针对汽轮发电机励磁与SM ES线性最优协调控制设计时出现的发电机端电压静态偏移问题,采用了积分线性最优控制设计方法。仿真表明:该控制规律能够很好地兼顾系统各状态量的动、静态特性,消除了发电机端电压的静态偏移,提高了系统的稳定运行能力。     

发电机励磁及SVC非线性最优协调控制

发电机励磁和静止无功补偿器(static var compensator,SVC)对远距离输电的稳定性有很大影响。为了提高系统在大扰动情况下的暂态稳定性,提出一种发电机励磁系统与SVC协调非线性最优控制方法。通过建立发电机励磁与SVC系统的综合模型,将微分几何反馈线性化理论与线性最优控制理论相结合,设计了发电机励磁与SVC系统的非线性最优协调控制规律。控制信号实现了本地化,避免了远距离的信号传输。仿真结果证明,该控制方法能同时改善系统的功角稳定性和电压稳定性。     

基于非线性最优和PID技术的综合励磁调节器研究

对于非线性系统的同步发电机而言，当它偏离系统工作点或系统发生较大扰动时，如果仍然采用基于PID技术的电力系统稳定器，就会出现误差。为此，可以将其用基于非线性最优控制技术的励磁调节器代替。但是，非线性最优控制调节器存在着对电压控制能力较弱的缺点。提出了一种能够将非线性最优励磁调节器和PID技术的电力系统稳定器有机结合的新型励磁调节器的设计原理，即把PID控制能在工作点有效控制和非线性最优控制能够精确描述同步发电机运行状态的优点结合起来，从而对发电机进行有效的控制。仿真验证表明：该方法是可行的。     

异步化同步发电机的最优励磁控制及其暂态分析研究

分析了异步化同步发电机的转子运动方程、励磁绕组动态方程及变频器频率调节暂态方程,从而建立了用于分析异步化同步发电机系统稳定性的暂态数学模型.对所建立的模型使用线性最优控制的方法,设计了异步化同步发电机系统的线性最优控制系统,仿真结果表明,变频器频率调节暂态方程是异步化同步发电机数学模型不可缺少的方程,并且所设计的励磁控制器能有效地改善系统的暂态稳定性.     

基于线性最优控制理论的励磁系统的设计及仿真

基于单机无穷大系统的线性化模型,结合线性最优控制理论建立了最优励磁控制器用的系统状态方程,求出线性最优励磁控制电力系统稳定器,用Matlab仿真软件在单机无穷大系统两种不同的运行状态下进行仿真,结果表明最优励磁控制具备了良好的电压性能,且给出了比AVR＋PSS更强的阻尼,表现出良好的动态特性。     

采用灰色预测控制算法的发电机最优励磁控制

在最优控制策略的基础上,提出了一种基于灰色预测控制算法的发电机最优励磁控制规律。采用GM(1,N)模型对各状态变量进行预测,根据最优控制理论求出含有预测信息的各状态变量的最优反馈增益,从而得到具有预测信息的最优控制量。灰色预测控制理论中灰色建模和“超前控制”的思想较好地弥补了线性最优控制理论中精确线性化和“事后控制”的不足。对单机无穷大系统的仿真结果表明,基于灰色预测控制算法的发电机最优励磁控制规律可明显改善电力系统在大小扰动下的动态特性,并且具有响应速度快的特点。     

EKF状态估计交流跟踪非线性L2励磁控制

针对传统非线性鲁棒自适应控制缺乏最优控制功能的不足,依据反演设计、直接反馈线性化和最优控制相关理论,提出了交流跟踪非线性鲁棒最优励磁控制方法。采用扩展卡尔曼滤波(EKF)估计和交流跟踪比较的方法,实现了用状态参数和发电机端电压的快速获取。依据估计和计算得到的状态参数,确定了励磁系统的运行点,最终实现了全运行状态的非线性鲁棒最优励磁控制。仿真结果表明:在动态条件下,EKF能够实现发电机状态的快速估计;交流跟踪基准电压信号能够快速跟踪发电机端电压的变化;非线性鲁棒最优自适应励磁控制既能实现不确定参数的自适应和L2增益干扰抑制,同时具备了传统反演设计不具备的最优控制功能。     

Neural-network-controlled superconducting magnetic energy storage for power system stabilization

It has been clarified that a superconducting magnetic energy storage (SMES) is very effective for power system stabilization. The control methods proposed for power system stabilization by SMES are the pole assignment, the optimal control, and so on, each of which, however, has its drawbacks. This paper is concerned with the power system stabilization by neural network control of the active power of SMES. First, the optimal stabilizing control of the SMES power for the model power system is calculated for various power system operating conditions and fault conditions. Then these optimal controls are used as training data for the neural network. The neural network used is a multilayer type with a feedback from the output layer to the input layer. The trained neural network is examined by untrained operating conditions and faults.     

基于神经网络的水轮机调节系统的自适应PID控制

基于有功功率反馈参与控制的水轮机调节系统,以几个典型工况下的最优ＰＩＤ系数作为训练样本,训练了一个三层ＢＰ神经网络,设计了一个用ＢＰ神经网络实现变参数的ＰＩＤ控制器;并构造了一个目标函数,设计了一个自适应神经元,利用神经元的自学习功能,在线优化控制器的输出,以期达到最优控制的目的。对简单电力系统的仿真结果表明,这种控制器可以达到较常规的变参数ＰＩＤ较好的控制效果,是实现水轮机调节系统自适应控制的一种可行的方法。     

一种基于离线策略表的实时变增益励磁控制器

设计了一种基于离线策略表的实时励磁控制器（RSLOEC）。利用发电机实际可能的运行样本依据最优控制原理离线形成反馈增益策略表。通过在线辨识出的样本组[Pe,Ut]经离线策略表插值拟合出最优反馈控制增益，以满足实时性的要求，从而弥补传统LOEC不能适应大干扰的明显缺陷，提高励磁系统的稳定性。给出了Matlab仿真软件包的实现及励磁系统采用RSLOEC提高稳定性的仿真结果。     

Experience replay–based output feedback Q‐learning scheme for optimal output tracking control of discrete‐time linear systems

This paper focuses on solving the adaptive optimal tracking control problem for discrete‐time linear systems with unknown system dynamics using output feedback. A Q‐learning‐based optimal adaptive control scheme is presented to learn the feedback and feedforward control parameters of the optimal tracking control law. The optimal feedback parameters are learned using the proposed output feedback Q‐learning Bellman equation, whereas the estimation of the optimal feedforward control parameters is achieved using an adaptive algorithm that guarantees convergence to zero of the tracking error. The proposed method has the advantage that it is not affected by the exploration noise bias problem and does not require a discounting factor, relieving the two bottlenecks in the past works in achieving stability guarantee and optimal asymptotic tracking. Furthermore, the proposed scheme employs the experience replay technique for data‐driven learning, which is data efficient and relaxes the persistence of excitation requirement in learning the feedback control parameters. It is shown that the learned feedback control parameters converge to the optimal solution of the Riccati equation and the feedforward control parameters converge to the solution of the Sylvester equation. Simulation studies on two practical systems have been carried out to show the effectiveness of the proposed scheme.     

葛洲坝二江电厂线性最优励磁控制器建模及参数优化

葛洲坝二江电厂线性最优励磁控制器以最优控制理论为基础，以机端电压，发电机有功出力和机端民量频率为状态量，以机组励磁电压为控制量，针对反馈增益的选择问题，在运用试探法进行仿真计算的基础上，从机组运行工况，转速测量和现场干扰等方面讨论了反馈增益国的选择原则，仿真计算和现场试验表明，所提出的模型和最优反馈增益是正确的，对提高华中电网的电压稳定水平是有益的，可以减少切换荷量。     

汽轮发电机组轴系扭振多指标非线性协调控制

为减少机电扰动对汽轮发电机组轴系扭振的影响,在单机无穷大系统中,建立了汽轮发电机组轴系、励磁和调速的六阶非线性状态空间数学模型。基于反馈精确线性化理论,设计了发电机组励磁和调速的多指标非线性协调控制(MINC)策略。同时与线性最优控制(LOC)方法做对比,仿真表明:采用MINC方法,当系统受到短路故障,调功和调压扰动时,不仅能更好地抑制汽轮机和发电机之间功角位移偏差的振荡,减少轴系扭振事故的发生,还可以兼顾各状态量的动、静态性能,提高电力系统稳定运行水平。     

Trapped mass estimation in automotive diesel engines based on in-cylinder pressure signal projection

Cylinder pressure signal provides key feedback information that allows for several engine monitoring and control capabilities. During the last few years, the use of cylinder pressure traces for advanced combustion strategies has become the focus of several research works. This is primarily due to the availability of reliable and inexpensive cylinder pressure sensors with expected durability that meets the vehicle lifetime. In this context, several approaches have been proposed to determine the engine trapped mass from the cylinder pressure measurements. A recent innovative approach for trapped charge determination based on a two-dimensional graphical signature is proposed in a previous work. The resulting estimator uses cylinder pressure signal as a unique input and allows to deduce the trapped mass on a cycle by cycle basis in steady and transient operating conditions. It has been validated in a wide range of engine operating conditions using instrumentation and industrial cylinder pressure sensors. This paper provides a theoretical framework and in-depth analysis for the signature based trapped mass estimator. A state-space model for in-cylinder conditions during the compression phase that complies with the signature modeling structure is developed. Extensive numerical investigations using an experimentally validated simulation platform are then performed. The objective is to select the optimal signature generation interval that reduces the impact of cycle to cycle fluctuations in terms of intake valve closing temperature and polytropic index. The obtained results are promising and clearly show the performance and robustness of the signature based trapped mass estimator that can provide relevant feedback information for adaptive engine control systems. It can be easily implemented for real-time monitoring and control in industrial automotive applications.     

An MPPT control scheme for a PV system utilizing limit cycle operation and its system design

This paper proposes a new simple maximum power point tracking (MPPT) control scheme for a PV system without using conventional “mountain climbing” optimum operating point searching technique. Although no information is needed on PV array, the generated output power is maximized by utilizing limit cycle phenomena occurring on the equilibrium/nonequilibrium boundary of system power flow. A parameter design procedure to determine operating period based on a theoretical model is presented. It has been found that the operating period of limit cycle is kept constant depending on the circuit and control parameters irrespective of the insolation conditions of PV array. Availability of the proposed new MPPT control scheme has been shown by simulation and experimental results. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(2): 67–75, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10134     

LCC谐振电路的优化移相控制

介绍一种采用移相调频优化控制方式的LCC谐振电路。在优化控制模式下电路实现软开关,降低开关损耗,同时改善变换器向电源反馈能量的过程,电源传输效率得到提高。详细分析了电路工作模式,利用基波分析的方法得到其数学模型,并采用数字锁相实现优化控制。实验结果证明该控制模式合理可行。