非均匀气隙永磁同步电机的有限时间混沌同步

针对非均匀气隙永磁同步电机(PMSM)混沌系统,提出一种改进的主动有限时间同步控制器.该控制器首先利用主动控制来实现动态误差系统非线性项和线性项的近似解耦,再通过有限时间稳定控制来实现驱动系统和相应系统的有限时间同步.通过仿真实验,验证了该控制器比传统的控制器具有更强的鲁棒性和快速响应能力.     

线性-滑模变结构的IPMSM直接转矩控制研究

为了提高内置式永磁同步电机(IPMSM)直接转矩控制系统的动态品质及鲁棒性,使系统在暂态、稳态过程中具有更优良的特性,提出了将直接转矩控制与线性-滑模变结构控制相结合的策略,分别采用转矩、磁链线性(PI)-滑模控制器取代了传统直接转矩控制中的滞环或PI控制器,该控制器分别根据转矩、磁链给定量与反馈量的误差动态调节平衡增益,使其实现线性控制与滑模开关控制的平衡关系,满足系统的控制需求。理论分析及实验结果表明,这种控制策略可极大地减小了磁链及转矩脉动,增大了调速范围,同时仍保持直接转矩控制固有的转矩快速响应特征,在负载恒定或突变条件下系统具有快速跟踪、鲁棒性强的优点,有效改善了系统的动、静态运行性能。     

基于非脆弱控制器设计的不确定模糊系统稳定性研究

研究不确定动态模糊系统的稳定性问题.提出一类不确定T-S动态模糊系统的非脆弱控制问题,并进行了控制器设计.首先给出不确定T-S动态模糊系统的模型;然后利用Lyapunov函数方法,研究连续不确定动态模糊系统的非脆弱控制器设计,得到基于LMI的不确定动态模糊系统的全局渐近稳定性条件.通过对一级倒立摆的不确定模糊非脆弱控制器设计的实例,表明了设计方法的可行性和有效性.     

具有有界控制输入线性多变量系统的渐近稳定性

基于连续时间系统向量比较定理,本文针对状态反馈控制器,带有观测器的状态反馈控制器和动态输出反馈控制器三种情况给出了控制输入有界时控制系统闭环渐近稳定性判据。     

连续混沌系统控制与同步的自适应方法

提出一种能大范围实现连续混沌系统控制与同步的连续自适应控制器。无论驱动系统处于何种状态 ,在连续自适应控制器控制下均可使响应系统按驱动系统给定轨道演化。该连续自适应控制器对系统参数不匹配及噪声干扰具有一定的鲁棒性。蔡氏电路混沌系统的数值仿真说明了所提出方法的有效性     

自然循环锅炉主蒸汽压力双值动态矩阵控制器

针对自然循环锅炉主蒸汽压力对象的大时滞和非线性的特性,将双值动态矩阵控制算法应用于锅炉燃烧系统蒸汽压力回路的控制中。考虑双值动态矩阵控制算法在模型失配和干扰影响下稳态精度低的问题,引入预测前馈补偿措施。基于分布式控制系统和可编程逻辑控制器编制程序实现了双值动态矩阵控制器,所设计的双值动态矩阵控制器模块具有可变采样和双向无扰动切换等功能。实验运行结果表明,双值动态矩阵控制计算量能满足快速采样频率的实时性要求,鲁棒稳定性、稳态精度、设定值跟踪速度、抗干扰能力和动态过渡过程均满足控制要求。     

基于LCL型有源电力滤波器的复合电流控制策略研究

针对传统电流控制策略存在高稳态精度与快速动态响应的矛盾,提出了一种基于LCL型有源电力滤波器的复合电流控制策略。该控制策略将比例积分控制和重复控制有机结合,在保证动态响应的基础上,利用PI控制器将控制模型补偿为稳定系统,使其在低频段具有良好的控制特性;利用重复控制器校正LCL型滤波器谐振峰和内环的固有相位滞后,实现电网谐波电流的快速跟踪与高精度补偿。实验结果表明,经过并联有源电力滤波器的谐波补偿,电网电流的总谐波失真明显减小,负载变化时并联有源电力滤波器可实现单周期快速响应,验证了所提出的复合电流控制策略的有效性。     

动态滑模控制在EAF电极调节系统中的应用

针对电弧炉电极调节系统的非线性、时变、模型不确定、大滞后等特点,结合高阶滑模和动态滑模控制的设计思想为其设计了一种动态滑模控制器,即通过微分环节构成新的切换函数,将不连续项转移到控制的一阶中,得到本质连续的动态滑模控制律,并将其应用到电弧炉电极调节系统中。对系统的阶跃响应和跟踪特性分别进行了仿真,仿真结果表明,所设计的动态滑模控制器不仅能使系统具有良好的动态性能和较强的跟踪特性,同时能有效地抑制系统的抖振,达到控制系统的动态品质要求。     

R(o)ssler混沌系统的自适应滑模控制

为了实现对R(o)ssler混沌系统的控制,使得系统的状态变量在有限时间内达到平衡点,将R(o)ssler混沌系统作为控制对象,提出了一种自适应滑模变结构控制策略,主要包括滑模面设计和自适应滑模控制率的设计.设计了一种比例积分滑模面,并通过李雅普诺夫稳定性理论证明了滑模动态方程的稳定性,为解决滑模控制器抖振问题设计了参数自适应的趋近律,有效地消除了滑模控制器的抖振.仿真结果显示,经自适应滑模控制后的R(o)ssler混沌系统状态能快速稳定地收敛到平衡点,并消除了控制器的抖振.结果证明该方法有效地实现了R(o)ssler混沌系统的控制,并具有良好的动态性能.     

连续非线性系统的神经网络α阶逆系统控制方法

对连续非线性系统,采用连续系统的设计方法,利用神经网络对非线性函数的逼近 能力加上用来表征系统动态特性的若干积分器,构造工程上可实现的原系统的神经网络α阶 逆系统(将α阶逆系统直接与原系统串接,构成α阶积分伪线性复合系统),并对α阶积分伪 线性复合系统设计线性控制器,实现对原非线性系统的有效控制.仿真结果表明,该方法适用 于较一般的线性、非线性连续系统,且结构简单,易于工程实现.     

State and mode feedback control strategy for discrete‐time Markovian jump linear systems with time‐varying controllable mode transition probability matrix

In this article, the state and mode feedback control strategy is investigated for the discrete‐time Markovian jump linear system (MJLS) with time‐varying controllable mode transition probability matrix (MTPM). This strategy, consisting of a state feedback controller and a mode feedback controller, is proposed to ensure MJLS's stability and meanwhile improve system performance. First, a mode‐dependent state feedback controller is designed to stabilize the MJLS based on the time‐invariant part of the MTPM such that it can still keep valid even if the MTPM is adjusted by the mode feedback control. Second, a generalized quadratic stabilization cost is put forward for evaluating MJLS's performance, which contains system state, state feedback controller, and mode feedback controller. To reduce the stabilization cost, a mode feedback controller is introduced to adjust each mode's occurrence probability by changing the time‐varying controllable part of MTPM. The calculation of such mode feedback controller is given based on a value‐iteration algorithm with its convergence proof. Compared with traditional state feedback control strategy, this state and mode feedback control strategy offers a new perspective for the control problem of general nonhomogeneous MJLSs. Numerical examples are provided to illustrate the validity of the proposed strategy.     

针对时变轨迹的非线性仿射系统的鲁棒近似最优跟踪控制

针对非线性连续系统难以跟踪时变轨迹的问题,本文首先通过系统变换引入新的状态变量从而将非线性系统的最优跟踪问题转化为一般非线性时不变系统的最优控制问题,并基于近似动态规划算法(ADP)获得近似最优值函数与最优控制策略.为有效地实现该算法,本文利用评价网与执行网来估计值函数及相应的控制策略,并且在线更新二者.为了消除神经网络近似过程中产生的误差,本文在设计控制器时增加一个鲁棒项;并且通过Lyapunov稳定性定理来证明本文提出的控制策略可保证系统跟踪误差渐近收敛到零,同时也验证在较小的误差范围内,该控制策略能够接近于最优控制策略.最后给出两个时变跟踪轨迹实例来证明该方法的可行性与有效性.     

线性连续时滞系统最优预见重复控制

针对一类线性连续时滞系统,提出一种最优预见重复控制设计方法.首先,通过一种等价变换,将被控时滞系统转化为无时滞系统.然后,利用L阶差分算子提升技巧,获得包含状态变量导数和跟踪误差的增广连续系统.在此基础上,通过定义一种新的性能指标,将预见重复控制设计问题转化为连续非自治系统的线性二次调节问题.进一步,基于最优控制理论,得到包含状态反馈、误差积分、重复控制、时滞补偿和预见补偿的最优预见重复控制器.该控制器包含了已有文献的多种控制器形式.最后,通过一个数值仿真实例,说明所提方法的有效性.     

A new sliding function for discrete predictive sliding mode control of time delay systems

The control of time delay systems is still an open area for research. This paper proposes an enhanced model predictive discrete-time sliding mode control with a new sliding function for a linear system with state delay. Firstly, a new sliding function including a present value and a past value of the state, called dynamic surface, is designed by means of linear matrix inequalities （LMIs）. Then, using this dynamic function and the rolling optimization method in the predictive control strategy, a discrete predictive sliding mode controller is synthesized. This new strategy is proposed to eliminate the undesirable effect of the delay term in the closed loop system. Also, the designed control strategy is more robust, and has a chattering reduction property and a faster convergence of the system s state. Finally, a numerical example is given to illustrate the effectiveness of the proposed control.     

A two-level control strategy with fuzzy logic for large-scale photovoltaic farms to support grid frequency regulation

This study proposes a two-level coordinated control strategy with fuzzy logic for appropriately adjusting the total active power supplied to a grid by large-scale photovoltaic (PV) farms in order to regulate grid frequency. For a solar farm, the strategy includes a central coordinating controller and many local controllers at PV power assemblies, treated as agents. In detail, the central controller uses a frequency regulation module based on a new automatic-tuning fuzzy-logic controller scheme to compute the appropriate reference values according to the total power needed. Then, the individual reference value for each local controller is determined. Each local controller governs all power-electronic converters installed at the PV agent to inject power into the grid according to the individual reference value received. Additionally, each local controller uses an algorithm to manage the state-of-charge of the battery bank installed at the agent so that it remains in the safe range of 20–80% while operating and close to the desired idle value of 50% at the steady state. Besides, a special control mode is developed and integrated into the overall strategy to aid rapid recovery of the grid frequency under emergency conditions. Numerical simulations demonstrate that the suggested strategy has the good response in terms of injecting an appropriate amount of power into the grid to regulate the frequency deviation into acceptable ranges of ±0.2 (Hz) in the transient state and ±0.05 (Hz) at the steady state, even when the weather conditions (solar radiation, air temperature), AC system load, and important control parameters of the grid suddenly change. Furthermore, the effectiveness in improving the grid-frequency stabilization by using the proposed strategy is validated within a four-area power system, where four PV farms are connected and the operating parameters of the grids at the areas are fairly different.     

基于扩张状态观测器和有限时间控制的感应电机直接转矩控制

对感应电机直接转矩控制系统中存在的干扰,本文结合扩张状态观测器(ESO)和有限时间控制(FTC)提出一种复合控制方法来提高系统的抗干扰能力.首先采用扩张状态观测器估算系统的扰动,用此观测值作为前馈量补偿到输入端;然后运用连续有限时间控制方法设计系统前向通道中的反馈控制器.文中对控制器的稳定性进行了证明.与传统的PI控制以及P+ESO控制方法进行仿真与实验结果比较,验证了方法的有效性.     

加热炉网络控制系统的最少拍响应控制策略

研究加热炉网络控制系统的最少拍响应控制策略。推导了加热炉网络控制系统的频域和离散型状态方程的数学模型,并采用时间戳神经网络,对不确定、时变的网络信息传输延时进行预测。重点研究了具有最少拍响应的数字控制器设计方法,导出了数字控制器控制算法。仿真结果表明,提出的控制算法实现了加热炉精确的温度控制,无稳态偏差,并具有良好的动、静态特性。     

Nonlinear inferential multi-rate control of Kappa number at multiple locations in a continuous pulp digester

The continuous pulp digester represents a large-scale, distributed parameter system. Control of the spatial profile of degree of cooking, characterized by the Kappa number, rather than its endpoint value can effectively control properties that are dependent on the history of cooking. However, profile control of such large-scale distributed parameter systems throws up new challenges in estimation and control. We design a nonlinear model predictive controller using a multi-rate extended Kalman filter to infer and control discrete points along the Kappa number profile. Both, the plant and controller models are based on first principles. The design is tested for significant mismatches in parameters, initial state errors, and stochastic disturbances in the entering wood composition.     

带有干扰观测器的高超声速飞行器滑模控制

针对高超声速飞行器非线性和易受干扰影响的特点,提出了带有扩张状态干扰观测器的连续滑模控制方法.在对飞行器非线性模型做线性化处理的基础上,设计了一种连续时间滑模控制器.该控制器在对不确定性和未知动态保持鲁棒性的基础上,消除了传统滑模中存在的抖振现象.对系统中存在的外加干扰,设计了扩张状态干扰观测器.将外加干扰作为系统的一个状态变量被估计出来,再将估计值用作滑模控制器的补偿量,进而达到消除外干扰的目的.在高超声速飞行器巡航飞行状态的基础上进行了仿真.仿真结果表明,所提出的方案能够满足控制要求.     

The preview control of a class of linear systems and its application in the fault-tolerant control theory

In the fault-tolerant control theory based on model following control, the desired signal of the control system is the output of a reference system. This paper is concerned with the design of the preview controller for a class of fault systems. A composite vector is introduced by including error vector, fault system state vector and reference system state vector. Then, we derived an augmented system from the known system equation, in which the reference input has equal status with the desired signal in the traditional preview control theory. Therefore, we can use the known theory to design the preview controller for the augmented system, then the preview controller of the original fault system can be obtained by the integration method. This paper strictly discusses the connection between stabilisation and detectability of the augmented system and the corresponding characteristics of the original system. Finally, by applying this theory to a real steam generator water level control system, it is found that the actions of the reference input preview and the fault signal preview can effectively eliminate the effect of the fault signal on the water level of the steam generator. The simulation shows the effectiveness of the controller designed.