Automatic tuning of robust constrained cross‐direction controllers

The paper machine cross‐directional (CD) process is a large‐scale spatially distributed system. It is known to be severely ill‐conditioned as the gain rolls down to zero for some of the process directions. Model uncertainties in the process are inevitable resulting in a challenging robust control design problem. CD actuators are subject to min–max constraints while slice lip actuators are subject to additional bending moment limits. Because of the large number of input constraints, the industrial practice is to tune the CD controller assuming inactive constraints. The robustness of CD feedback loops to model uncertainties under constrained internal model control satisfies an integral quadratic inequality. This work develops an automatic tuning algorithm that guarantees robust stability and performance of the constrained CD feedback loop. Spatial response models are identified in a prediction error frame delivering bounds on the CD process pseudo‐singular values. The CD controller is synthesized online through a linear matrix inequalities feasibility problem taking into consideration the modal space uncertainty rising from the uncertainties in the estimated parameters and the expected variations in the dynamic response. The developed tuning technique is suitable for paper machines producing different grades of paper as the CD process spatial and dynamic responses change for each grade. The performance of the tuned constrained internal model control controller is validated through comparing it to an industrial CD controller that has been implemented in paper mills as part of a commercial product. Copyright © 2015 John Wiley & Sons, Ltd.     

过热汽温的稳定自适应预测函数控制

针对火电厂锅炉过热蒸汽温度的动特性设计了一种基于Laguerre模型的稳定自适应预测函数控制器。通过对闭环系统状态方程的稳定性分析，依据Lyapunov稳定性定理得到了控制系统稳定的必要条件。对于不同负荷情况下模型发生跳变所引起的不稳定，该文提出一种衰减因子补偿校正方法，并使用混沌算法在线寻优调节衰减因子，提高了控制品质。仿真研究中根据多模型切换性能指标函数来判断模型跳变，当负荷变化时，在线辨识模型参数，得到较好的控制结果，证明该算法的有效性。     

A gain‐scheduled control algorithm for input constrained systems to track time‐varying references using controller state resets

In this paper, we propose a control law for a discrete‐time linear system with actuator saturation to track time‐varying reference signals. The proposed control law consists of a feedback controller and a target recalculation mechanism. The feedback controller includes an integrator to achieve zero steady‐state error in the case where the reference signal is constant. The feedback gains of the controller are parameterized by a single scheduling parameter. In the proposed control algorithm, when the tracking error is large, a modified reference signal is computed by the target recalculation mechanism so that feasibility of the algorithm and stability of the control system are guaranteed at all times. At this stage, the controller state is modified online so that the tracking control performance is improved. Further, when the tracking error becomes small, the scheduling parameter and the controller state are updated simultaneously so that the tracking control performance is improved. The problems of determining the scheduling parameter, the controller state, and the modified reference signal are reduced to convex optimization problems with linear matrix inequality constraints. The effectiveness of the proposed control method is shown through an experiment. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于深度置信网络状态最优反馈的智能发电控制策略

针对自动发电控制问题中的状态信息测取和最优发电控制策略的难题,结合深度置信网络与最优控制理论,提出了一种应用于自动发电控制领域的深度置信网络状态最优反馈算法。首先,设计了一种适用于发电控制问题的全状态最优反馈控制策略,并引入了深度置信网络学习全状态最优反馈控制特性,以深度置信网络的非线性表达能力弥补传统线性控制的不足,进而实现了非全状态信息反馈下的近似最优发电控制,有效解决了最优发电控制问题中的状态信息测取难题,同时提升了自动发电控制性能。在IEEE标准两区域系统的算例仿真结果表明,所提算法可以实现由自区域频率偏差与传输功率偏差组合反馈下的系统近似最优发电控制,验证了所提方法的有效性、可行性和强鲁棒性。     

Reduced‐order robust adaptive control design of uncertain SISO linear systems

In this paper, a stability and robustness preserving adaptive controller order‐reduction method is developed for a class of uncertain linear systems affected by system and measurement noises. In this method, we immediately start the integrator backstepping procedure of the controller design without first stabilizing a filtered dynamics of the output. This relieves us from generating the reference trajectory for the filtered dynamics of the output and thus reducing the controller order by n, n being the dimension of the system state. The stability of the filtered dynamics is indirectly proved via an existing state signal. The trade‐off for this order reduction is that the worst‐case estimate for the expanded state vector has to be chosen as a suboptimal choice rather than the optimal choice. It is shown that the resulting reduced‐order adaptive controller preserves the stability and robustness properties of the full‐order adaptive controller in disturbance attenuation, boundedness of closed‐loop signals, and output tracking. The proposed order‐reduction scheme is also applied to a class of single‐input single‐output linear systems with partly measured disturbances. Two examples are presented to illustrate the performance of the reduced‐order controller in this paper. Copyright © 2007 John Wiley & Sons, Ltd.     

One‐cycle controlled quadratic buck converter

The quadratic DC‐DC converter can broaden the voltage conversion ratio, which meets the requirements of wide input voltage. However, large‐scale variation of input voltage puts forward harsh requirements on ability to resist input disturbance of control strategy. Quadratic buck converter (QBC) is pulsed nonlinear dynamic systems, so the one‐cycle control strategy based on robustness principle may provide better rejection of power source than the linear feedback control. But the traditional one‐cycle controlled QBC (TOCCQBC) suffers from poor ability against load disturbance and steady‐state error. To overcome aforementioned shortages, an improved OCCQBC is proposed by adding inductor current to diode voltage as integral variable and introducing feedback of output voltage. The paper first introduces the working principle of the QBC, and second, the OCCQBC is presented. Then, a mathematical model using small signal analysis of the OCCQBC is established, and an experimental prototype with a power of 6 W is set up. Simulation and experimental results verify the correctness of the theoretical analysis and the feasibility of the strategy.     

基于遗传算法的永磁同步直线电机PID控制研究

由于永磁同步直线电机系统运行过程中参数摄动和负载扰动等问题的存在,传统 PID控制器无法满足高精度伺服控制系统的要求。设计出一种基于遗传算法(GA)优化的 PID 控制器,并通过 Simulink 对永磁同步直线电机控制系统进行建模和仿真实验。仿真和实验表明,采用 GA优化的PID控制器与传统的 PID控制器在指定速度和负载扰动条件下相比,具有更好的动态稳定性和跟踪性能,能有效抑制参数摄动的影响并对负载扰动具有较强的鲁棒性,实验结果也证明了方案的有效性和可行性。     

Robust control and data‐driven tuning of a hybrid integrator‐gain system with applications to wafer scanners

A hybrid integrator‐gain system is discussed that aims for improved low‐frequency disturbance rejection, while, at the same time, does not deteriorate overshoot and settling times when compared with a linear integrator. The hybrid integrator has similar phase advantages as the well‐known Clegg integrator but without inducing the discontinuous behavior resulting from resetting system state values. Optimal tuning of the controller parameters of the hybrid integrator is strongly influenced by machine‐specific properties and therefore favors a data‐driven optimization approach. However, as a time‐domain optimization algorithm can easily lead to nonrobust solutions in the sense of large peaking of the closed‐loop frequency response functions, frequency‐domain robustness constraints will be imposed. By means of an adaptive weighting filter design, the parameter updates are penalized upon violation of said robustness constraints. Posed in an unconstrained problem formulation, this is subsequently solved by applying a Gauss‐Newton–based parameter update scheme. Closed‐loop stability of the linear time‐invariant plant and controller in feedback connection with a hybrid integrator‐gain system element follows from a circle‐criterion‐like analysis, which is based on evaluating (measured) frequency response data. Measurement results obtained from an industrial wafer scanner demonstrate the effectiveness of the approach.     

直流配电网下垂参数小干扰稳定优化调控方法

以基于下垂控制的直流配电网为研究对象,推导建立了下垂控制模式下典型环状直流配电网的小信号状态空间模型,对传统下垂参数经济优化模型中存在的系统调控不稳定问题进行了分析,进而提出了考虑小干扰稳定约束的直流配电网下垂参数优化调控方法,以确定性预测场景和极端场景下直流配电网小信号状态方程的特征值谱横坐标作为系统小干扰稳定约束,来优化系统网损。此外,为求解该模型,针对传统算法中存在的易陷入局部最优解、特征值迭代误差积累和计算效率较低等问题,在序列非线性规划算法和遗传算法的基础上提出了改进策略。数值实验结果表明,该优化模型在保证系统小干扰稳定的前提下能较大程度地提升系统运行经济性,同时提高系统适应不确定源荷功率随机波动的鲁棒性;所提出的算法改进策略可以在保证优化结果可靠有效的前提下,提高算法的寻优能力和计算效率。     

全桥型DC/DC变换器的DMC-PID串级控制策略研究

研究了全桥型DC/DC变换器系统的控制方法。针对现有DC/DC变换器动态响应速度慢、抗干扰能力差的现状,提出了基于状态反馈精确线性化的动态矩阵控制-比例积分微分DMC-PID（dynamic matrix control-propor-tional integral differential）串级控制方法。应用状态空间平均法建立全桥型DC/DC变换器系统的非线性模型,通过状态反馈精确线性化后得到线性化系统。为使系统获得优良的控制性能,选取DMC-PID串级控制方法。该控制方法同时具备PID算法的鲁棒性和DMC算法的快速性和稳定性,能有效地解决电源输入电压大范围波动输出电压不能及时稳定的问题。通过仿真分析和实验验证了该方案能在各种扰动工作条件下实现对变换器输出精确、快速的控制。     

A new adaptive backstepping control algorithm for motion control systems — an implicit and symbolic computation approach

A new adaptive integral backstepping control algorithm for motion control systems is proposed. The design approach is non‐conventional in that it only implicitly incorporates error states into a design Lyapunov function and computes time derivative of the Lyapunov function symbolically to the point of getting parameter estimate update laws on which desirable structures are imposed. The closed‐loop error system turns out to be linear and time‐varying and can be reformulated as a linear–non‐linear cascade system. Uniform exponential stability or absolute stability can be achieved. The design is robust against system parameter variations. The effectiveness and robustness of the control algorithm are verified by numerical examples. Copyright © 2002 John Wiley & Sons, Ltd.     

Adaptive saturated finite‐time control algorithm for buck‐type DC‐DC converter systems

To enhance the convergent rate and robustness of buck‐type DC‐DC converter system, a new finite‐time voltage regulation control algorithm is proposed in this paper. First, an average state space‐based model is analyzed, which considers both the parameters uncertainties and the variations of load and input voltage. By using saturation finite‐time control theory, at the first step, in the absence of disturbance, a new fast voltage regulation control algorithm is designed, which can guarantee that the output voltage converges to the reference voltage in a finite time. Because the saturation constraint is considered during the controller design, the duty ratio function of the converter satisfies the constraint between 0 and 1. Second, in the presence of disturbance, a finite‐time convergent disturbance observer is designed to estimate the unknown disturbances in a finite time. Finally, a disturbance observer‐based finite‐time voltage regulation control algorithm is developed. Compared with PI (Proportional‐Integral) control algorithm, circuit simulations show that the proposed algorithm has a faster regulation performance and stronger robustness performance on disturbance rejection.     

基于逆系统内模算法的交流励磁发电机

在建立交流励磁发电机空间状态方程的基础上,运用逆系统方法将交流励磁发电机精确线性化成有功功率和无功功率两个一阶线性子系统,并运用内模控制算法对其进行优化以提高系统的稳定性。提出了交流励磁发电机的基于逆系统内模控制策略,并进行了仿真实验。仿真结果表明,该方法能够实现对发电输出功率的解耦控制,并具有更高的控制精确度和稳定性。     

基于CIM的配网理论线损在线计算系统

针对传统配电网线损计算系统实时性和准确性低,并且存在"信息孤岛"的问题,提出一种基于公共信息模型的配电网线损计算系统。该系统能够读取SCADA,GIS和DMIS等信息系统的数据,并通过XML和SVG语言实现数据交互。线损计算模块采用前推回代潮流算法充分利用采集到的实时数据进行计算,提高了计算的实时性和准确性。实例分析表明了系统的可行性与实用性。     

基于DMPC加权一致性算法的电池储能阵列分组控制策略

为了解决由多个电池单元组成的大容量电池储能阵列系统(BESAS)的优化运行问题,提出了一种基于分布式模型预测控制的加权一致性算法。首先,介绍了含风电场BESAS的构成,将多个电池储能单元划分为充电组和放电组,通过制定合理的组间协调策略,在不影响BESAS额定功率的前提下,提高储能系统的容量利用率和减少充/放电转换次数;然后,详细地介绍了所提分布式算法的计算过程,并将该算法应用于BESAS的分组控制过程,实现兼顾电池单元安全运行的功率自适应分配;最后,通过算例从算法性能和BESAS控制性能2个方面进行仿真验证,结果表明所提算法和分组控制策略在鲁棒性和控制效果方面均具有一定的优势和可行性。     

基于PI迭代学习的有源电力滤波器的电流控制方法

针对有源电力滤波器存在滤波效果不够理想这一问题。根据系统的参考信号是周期变化的特点．提出了一种基于PI型学习律的迭代学习控制算法。通过实施遗忘因子学习律增强系统鲁棒性的同时。引入了在最优目标下选择模糊参考电流误差的D型学习律前馈环节。并且利用PSIM软件对所提出方法和传统的滞环控制方法进行了仿真实验。从动态响应和控制精度两个方面做了比较。验证了所提出方法的可行性。     

The analysis of average sliding control method applied on Sheppard–Taylor power factor correction converter

This paper presents an average sliding control (ASC) method to be used in power factor correction (PFC) converters to decrease the total harmonic distortion (THD) of the input current by eliminating the input current harmonics. The ASC algorithm is adapted to digital signal processor due to its well-known properties such as robustness, stability and good regulation in a wide range of operating conditions. The control approach is operated in continuous conduction mode. In this approach, all the duty cycles required to achieve unity power factor in a half line period are calculated in advance using ASC method. The feed forward is also used in the control algorithm using rms value of the input voltage. The implementation of feed forward improves the converter performance to obtain a near unity power factor correction with a lower input current THD. The converter used in simulation and experimental studies is a Sheppard–Taylor PFC converter. The stability analysis of proposed control method is performed with the effect of changes in input voltage and load. In addition, the performance of ASC method is compared with UC3854AN traditional analog PFC control method. The experiments performed in the laboratory for different cases of operation verify the theoretical and simulation studies performed in MATLAB/Simulink. The experimental results are satisfied by IEC 61000-3-2 Current Harmonic Standard.     

永磁同步电机自抗扰控制系统设计及扩张状态观测器参数特性分析

针对传统永磁同步电机矢量控制系统采用的 PI速度控制算法存在参数鲁棒性差 抗干扰能力弱等问题, 提出了一种基千一阶线性自抗扰控制( LADRC) 速度控制器的永磁同步电机矢量控制方案。 分析了线性扩展状态观测器 ( LESO) 的跟踪收敛性能和噪声滤波性能。 然后总结了 LESO的带宽参数设置规则。 最后通过仿真验证了 LADRC速度控制器的性能和 LESO带宽参数设置规则的有效性。