基于模糊PID控制的光伏系统最大功率点跟踪

由于光伏系统的输出功率随着外界环境和负载的变化而变化,为了提高光伏系统的效率,需要对其进行最大功率点跟踪[1]。模糊控制属于有差控制,在最大功率点附近仍有震荡的存在,为了进一步改进跟踪性能,提出将模糊PID控制代替模糊控制。根据控制对象建立合适的控制规则表、PID控制器,实现参数的在线优化。仿真结果表明,改进方法能快速、准确地跟踪光伏电池的最大功率点,避免在最大功率点的震荡,同时提高转换效率。     

H∞Fuzzy State‐Feedback Control Plus State‐Derivative‐Feedback Control Synthesis for Photovoltaic Systems

This paper addresses the problem of designing an H_∞fuzzy state‐ feedback (SF) plus state‐derivative‐feedback (SDF) control system for photovoltaic (PV) systems based on a linear matrix inequality (LMI) approach. The TS fuzzy controller is designed on the basis of the Takagi‐Sugeno (TS) fuzzy model. The sufficient condition is found such that the system with the fuzzy controller is asymptotically stable and an H_∞performance is satisfied. First, a dc/dc buck converter is considered to regulate the power output by controlling state and state‐derivative variables of PV systems. The dynamic model of PV systems is approximated by the TS fuzzy model in the form of nonlinear systems. Then, based on a well‐known Lyapunov functional approach, the synthetic is formulated of an H_∞fuzzy SF plus SDF control law, which guarantees the L₂‐gain from an exogenous input to the regulated output to be less than or equal to some prescribed value. Finally, to show effectiveness, the simulation of the PV systems with the proposed control is assessed by the computer programme. The proposed control method shows good performance for power output and high stability for the PV system.     

Static Output Feedback Control for Interval Type‐2 T‐S Fuzzy Systems Based on Fuzzy Lyapunov Functions

This study aims to design an interval type‐2 (IT2) fuzzy static output feedback controller to stabilize the IT2 Takagi‐Sugeno (T‐S) fuzzy system. Conservative results may be obtained when a common quadratic Lyapunov function is utilized to investigate the stability of T‐S fuzzy systems. A fuzzy Lyapunov function is employed in this study to analyze the stability of the IT2 fuzzy closed‐loop system formed by the IT2 T‐S fuzzy model and the IT2 fuzzy static output feedback controller. Stability conditions in the form of linear matrix inequalities are derived. Several slack matrices are introduced to further reduce the conservativeness of stability analysis. The membership‐function shape‐dependent analysis approach is also employed to relax the stability results. The numerical examples illustrate the effectiveness of the proposed conditions.     

Cooperative Adaptive Fuzzy Output Feedback Control for Synchronization of Nonlinear Multi‐Agent Systems in the Presence of Input Saturation

This paper considers the leader‐following synchronization problem of nonlinear multi‐agent systems with unmeasurable states in the presence of input saturation. Each follower is governed by a class of strict‐feedback systems with unknown nonlinearities and the information of the leader can be accessed by only a small fraction of followers. An auxiliary system is introduced and its states are used to design the cooperative controllers for counteracting the effect of input saturation. By using fuzzy logic systems to approximate the unknown nonlinearities, local adaptive fuzzy observers are designed to estimate the unmeasurable states. Dynamic surface control (DSC) is employed to design distributed adaptive fuzzy output feedback controllers. The developed controllers guarantee that the outputs of all followers synchronize to that of the leader under directed communication graphs. Based on Lyapunov stability theory, it is proved that all signals in the closed‐loop systems are semiglobally uniformly ultimately bounded (SGUUB), and the tracking error converges to a small neighborhood of the origin. An example is provided to show the effectiveness of the proposed control approach.     

光伏发电系统中蓄电池充放电状态的模糊控制

提出一种基于模糊控制的光伏发电系统蓄电池充放电状态控制策略,可克服常规控制方法存在的缺点。控制策略中取蓄电池的端电压、端电压变化和温度变化作为输入变量,蓄电池的充放电状态作为输出变量。由蓄电池的端电压、端电压变化和温度的变化经模糊推理得到蓄电池的充放电状态。该控制策略能提高蓄电池充放电状态判断的准确性。在充分利用太阳能电池阵列输出能量的同时达到提高蓄电池使用寿命的目的。     

DSP+PLC主从结构实现电压和无功模糊控制策略

从中、小型变电站的数学模型入手，通过数学模型地推导，指出单一的PLC控制在无人变电站控制决策中无法高速处理数据的局限，由此提出以DSP PLC主从式结构实现无人变电站的电压和无功模糊智能自动控制策略。具体介绍了采用DSP为计算核心完成基于模糊边界的电压、无功九域图控制策略判断，由PLC完成具体的电气控制操作的实施方案，并且详细介绍了DSP和PLC之间的通信实现。     

基于模糊神经网络的自适应流量反馈控制策略研究

介绍了一种由工控机、PLC、触摸屏、传感器组成的机场油库油泵模糊神经网络控制系统,阐述了该系统的工作原理和设计过程。     

基于DSP28335的有源电力滤波器测控系统设计

为解决有源电力滤波器在现场工作中的准确监测与可靠控制问题,设计并实现了一种基于DSP28335的有源电力滤波器测控系统.主要对数据采集模块、通信模块、人机交互模块的硬件电路进行了详细介绍,对监测参数计算、SPI通信、故障处理的软件功能进行了阐述,给出了硬件结构和软件流程.实验结果表明系统满足设计要求,实现了对有源电力滤波器实时准确监测并可靠控制的目的.     

Recursive Back‐Stepping Design of An Adaptive Fuzzy Controller for Strict Output Feedback Nonlinear Systems

In this paper, a back‐stepping adaptive fuzzy controller is proposed for strict output feedback nonlinear systems. The unknown nonlinearity and external disturbances of such systems are considered. We assume that only the output of the system is available for measurement. As a result, two filters are constructed to estimate the states of strict output feedback systems. Since fuzzy systems can uniformly approximate nonlinear continuous functions to arbitrary accuracy, the adaptive fuzzy control theory combined with a tuning function scheme is developed to derive the control laws of strict output feedback systems that possess unknown functions. Moreover, the H∞ performance condition is introduced to attenuate the effect of the modeling error and external disturbances. Finally, an example is simulated in order to confirm the applicability of the proposed method.     

Dynamic Output‐Feedback Control for T‐S Fuzzy Systems with Input Time‐Varying Delay

This paper considers the problem of the control for T‐S fuzzy systems with input time‐varying delay via dynamic output feedback. Firstly, by applying the reciprocally convex approach, new delay‐dependent sufficient condition for performance analysis is obtained. Then, a less conservative condition for the existence of the controllers is given in terms of linear matrix inequalities (LMIs). Moreover, in the considered system, the time‐delay term is included in the measured output. This results in the difficulty in designing the controllers being increased and the obtained results being applied to a wider class of fuzzy systems than the most existing ones. The main contribution of this work lies in the application of the reciprocally convex inequality and the time‐delay term included in the measured output. Finally, the advantages and effectiveness of the present results are shown by several numerical examples.     

基于模糊观测器T-S模型和自适应模糊逻辑系统的一类非线性系统的H∞控制

针对一类非线性系统，把模糊T-S模型和自适应模糊逻辑系统两类模糊逻辑方式结合起来，提出了一种基于观测器的控制方案．首先，应用模糊T-S模型对非线性系统建模，设计观测器来观测系统状态；由线性矩阵不等式得到模糊模型的控制律．其次，应用自适应模糊逻辑系统作为补偿器来补偿建模误差．证明了闭环系统满足期望的性能．仿真结果表明了该方案的可行性．     

基于模糊逻辑算法的纯电动客车起步加速能力优化与再生制动控制

日益严重的环境问题促使城市交通向着清洁、高效和可持续的方向发展,同时也促进了新能源交通技术的推广和应用。随着电池和电机驱动技术的发展,纯电动客车也受到越来越多的关注。起步加速能力和可再生制动是纯电动公交车区别于传统内燃机车的两个方面。由于加速踏板信号响应与驱动电机响应较快,理论上纯电动客车的加速性能要优于传统内燃机车。再生制动是一种降低能耗、提高续驶里程的重要技术手段。文章基于模糊逻辑算法,设计了驱动扭矩控制策略对驱动工况下的纯电动客车起步加速能力进行优化。同时,针对纯电动客车制动工况设计了能量回收策略。结果表明,驱动扭矩控制策略可使纯电动客车起步加速时间从19.7 s减小至19.25 s,制动能量回收策略在中国典型城市公交路况下使能量消耗减少11%。     

Novel Optimal Design Approach for Output‐Feedback H∞ Control of Vehicle Active Seat‐Suspension System

In this paper, the output‐feedback control problem of a vehicle active seat‐suspension system is investigated. A novel optimal design approach for an output‐feedback H_∞ controller is proposed. The main objective of the controller is to minimize the seat vertical acceleration to improve vehicle ride comfort. First, the human body and the seat are considered in the modeling of a vehicle active suspension system, which makes the model more precise. Other constraints, such as tire deflection, suspension deflection and actuator saturation, are also considered. Then the output‐feedback control strategy is adopted since some state variables, such as body acceleration and body deflection, are unavailable. A concise and effective approach for an output‐feedback H_∞ optimal control is presented. The desired controller is obtained by solving the corresponding linear matrix inequalities (LMIs) and by the calculation of equations proposed in this paper. Finally, a numerical example is presented to show the effectiveness and advantages of the proposed controller design approach.     

Robust Adaptive Fuzzy Control of Nonlinear Systems with Unknown and Time‐Varying Saturation

In this paper, a robust adaptive fuzzy control approach is proposed for a class of nonlinear systems in strict‐feedback form with the unknown time‐varying saturation input. To deal with the time‐varying saturation problem, a novel controller separation approach is proposed in the literature to separate the desired control signal from the practical constrained control input. Furthermore, an optimized adaptation method is applied to the dynamic surface control design to reduce the number of adaptive parameters. By utilizing the Lyapunov synthesis, the fuzzy logic system technique and the Nussbaum function technique, an adaptive fuzzy control algorithm is constructed to guarantee that all the signals in the closed‐loop control system remain semiglobally uniformly ultimately bounded, and the tracking error is driven to an adjustable neighborhood of the origin. Finally, some numerical examples are provided to validate the effectiveness of the proposed control scheme in the literature.     

基于SCADA的配电站电压无功实时监控

提出一种基于ＳＣＡＤＡ的综合控制变压器分接头和并联电容器组的模糊线性规划方法,进行配电站电压无功实时监控。通过推导配电站二次母线电压Ｖ２的方程,建立各物理量的录属函数及模糊目标函数;运用９域图和线性规划方法,得到使Ｖ２偏差最小的最优调控策略,该 实际应用中取得了良好的效果。     

自适应模糊PID控制在火电厂给水加药中的应用

高参数、大容量机组成为火电厂发展的趋势,为了保证机组的安全经济运行,对热力系统汽水指标的控制提出了更严格的要求.而调节锅炉给水水质的加药过程具有大滞后、非线性、时变等特性,常规的控制方法难以获得满意的控制效果.针对火电厂给水加药系统的特点,将模糊控制引入到锅炉给水加药控制系统中,提出将模糊控制与常规PID控制相结合的思路,设计自适应模糊PID控制模型,仿真研究了控制器的动态性能.仿真结果表明,该方法具有较好的动态品质和调节精度.现场运行实验结果也表明了该方法的有效性.     

Simultaneous Design of Parallel Distributed Output Feedback and Anti‐windup Compensators for Constrained Takagi‐Sugeno Fuzzy Systems

This paper is devoted to developing a novel approach to deal with constrained continuous‐time nonlinear systems in the form of Takagi‐Sugeno fuzzy models. Here, the disturbed systems are subject to both input and state constraints. The one‐step design method is used to simultaneously synthesize the dynamic output feedback controller and its anti‐windup strategy. A parameter‐dependent version of the generalized sector condition is used together with Lyapunov stability theory to derive linear matrix inequality design conditions. Based on this result and for different design specifications, the synthesis of an anti‐windup based dynamic output feedback controller is expressed on the form of convex optimization problems. A physically motivated example is given to illustrate the effectiveness of the proposed method.     

Stabilization of Hybrid Systems by Feedback Control Based on Discrete‐Time State and Mode Observations

Recently, a kind of feedback control based on discrete‐time state observations was proposed to stabilize continuous‐time hybrid stochastic systems in the mean‐square sense. We find that the feedback control there still depends on the continuous‐time observations of the mode. However, it usually costs to identify the current mode of the system in practice. So we can further improve the control to reduce the control cost by identifying the mode at discrete times when we make observations for the state. In this paper, we aim to design such a type of feedback control based on the discrete‐time observations of both state and mode to stabilize the given hybrid stochastic differential equations (SDEs) in the sense of mean‐square exponential stability. Moreover, a numerical example is given to illustrate our results.     

Globally Stable Adaptive Tracking Control for Uncertain Strict‐Feedback Systems Based on Neural Network Approximation

This paper addresses the problem of globally stable adaptive neural tracking control for a class of strict‐feedback nonlinear systems. Compared with the existing works, the salient properties of the proposed scheme are given as follows. First, a novel switching controller is developed, which consists of a traditional adaptive neural controller and an extra robust controller to pull back the transient outside of the approximation domain. Second, only two adaptive parameters need to be tuned online, and the computational burden is considerably alleviated in practice. Third, to design the desired switching controller via the backstepping technique, a novel switching function, which has continuous derivatives up to the nth order, is constructed. It is shown that the system output converges to a small neighborhood of the reference signal and the closed‐loop system is globally stable. Finally, an example is provided to verify the effectiveness of the proposed control method.