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1.
How to design a set of optimal distributed load frequency controllers for a multi-area interconnected power system is an important but still challenging issue in the field of modern electric power systems. This paper presents an adaptive population extremal optimization-based extended distributed model predictive load frequency control method called PEO-EDMPC for a multi-area interconnected power system. The key idea behind the proposed method is formulating the dynamic load frequency control issue of each area power system as an extended distributed discrete-time state-space model based on an extended state vector, obtaining a distributed dynamic extended predictive model, and rolling optimization of real-time control output signal by adopting an adaptive population extremal optimization algorithm, where the fitness is evaluated by the weighted sum of square predicted errors and square future control values. The superiority of the proposed PEO-EDMPC method to a traditional distributed model predictive control method, a population extremal optimization-based distributed proportional-integral control algorithm and a traditional distributed integral control method is demonstrated by the simulation studies on two-area and three-area interconnected power systems in cases of normal, perturbed system parameters and dynamical load disturbances.  相似文献   

2.
This paper considers a class of optimal control problems governed by Markov jump systems. Our focus is to develop a computational method, based on the control parametrization approach, for solving this class of optimal control problems. Due to the existence of the continuous-time Markov chain, the optimal control problem under consideration is a stochastic optimal control problem, and hence the control parametrization technique cannot be applied directly. For this, a derandomization approach is introduced to obtain a representative deterministic optimal control problem. Then, the control parametrization method is applied to obtain an approximate finite dimensional optimization problem which can be computed numerically using the gradient-based optimization method. For this, the gradient formulas of the cost function and the constraint functions with respect to control variables are derived. Finally, a practical application involving a RLC circuit model is solved using the method proposed.  相似文献   

3.
In the islanded microgrid (MG), to improve the control effect of the output voltages of DERs and keep the economical operation of MG, a consensus-based economic hierarchical control strategy is proposed in this paper. The corresponding control structure is divided into physical and cyber layers, where the cyber layer is mainly composed by communicators. In these two layers, there are two main designs: the consensus-based primary control (CBPC) method and the secondary control (CBSC) method. In CBPC: Firstly, the undirected communication path among communicators is designed by path planning. Then, based on the constructed path, an economic P–U droop control method considering with line loss and flexible load is realized by using consensus control. In CBSC: Firstly, a cyber-physical vulnerability assessment method is designed. Based on this method, the DER with the lowest vulnerability is selected to be connected with the “virtual leader”. And when the data transmission behavior of the undirected communication path is selected, the undirected network can be transferred as a directed network. Thus, it can make the virtual leader-following consensus control (VLFCC) and the secondary control on voltage accomplished. Finally, the simulation results show the effectiveness of the proposed strategy.  相似文献   

4.
In this paper, a numerical method to solve nonlinear optimal control problems with terminal state constraints, control inequality constraints and simple bounds on the state variables, is presented. The method converts the optimal control problem into a sequence of quadratic programming problems. To this end, the quasilinearization method is used to replace the nonlinear optimal control problem with a sequence of constrained linear-quadratic optimal control problems, then each of the state variables is approximated by a finite length Chebyshev series with unknown parameters. The method gives the information of the quadratic programming problem explicitly (The Hessian, the gradient of the cost function and the Jacobian of the constraints). To show the effectiveness of the proposed method, the simulation results of two constrained nonlinear optimal control problems are presented.  相似文献   

5.
Control performance of the industrial process is inevitably influenced by the measurement noises and non-Gaussian external disturbances. This influence has not been fully considered in the traditional variance-based controller design. To reduce the influence, a novel scheme that can enhance the control performance is developed by integrating dynamic data reconciliation (DDR) into minimum rational entropy control (MREC) in this paper. Firstly, the influence of measurement noise is fully considered, and a novel DDR method is proposed to deal with the minimum entropy control (MEC) process such that the influence of measurement noise can be reduced, and the control performance will be improved. Then, based on the DDR-MREC performance index, a benchmark for evaluating the control performance of non-Gaussian systems is established. Finally, the proposed control performance assessment (CPA) method is applied to the wind energy conversion system and compared with the CPA method based on DDR-minimum variance control. The experimental results have demonstrated that the proposed new method is more effective than existing works.  相似文献   

6.
The requirement for An electrical grid-connected wind turbine is that the synchronous generator speed is stable within a required speed range for the electrical grid. In this paper, a hydraulic wind turbine (HWT) system is considered, and the working principle and working conditions of the HWT are introduced. A novel speed control method is proposed in this paper, using both a proportional flow control valve and a variable displacement motor, which are adjusted in combination to control the speed of the HWT. By establishing a state space model of the HWT and solving the nonlinear system with a feedback linearization method, a bivariate tracking controller is constructed to realize accurate speed control under fluctuating wind speed and the load disturbance conditions. The effectiveness of the control method is verified by simulation, but experimental results highlight problems with the method. The theoretical controller is simplified to reduce sensitivity to measurement noise and modeling error. The control effect has been improved to some extent, but it is limited. Based on these results, combined with the sliding mode variable structure control method and the feedback linearization method to solve the problem of measurement noise and modeling error, and the effectiveness of the control law is finally verified experimentally. It lays a theoretical foundation for the practical application of HWT.  相似文献   

7.
Stabilization problem for a linear plant with time delay control is considered. A new method of the sliding mode control design minimizing the effects of system disturbances is presented. It is based on a combination of the well-known predictor-based sliding mode control algorithm with the recently developed invariant ellipsoid method. The theoretical results are supported by numerical simulations.  相似文献   

8.
In this article, the fault-tolerant control is investigated for the spacecraft attitude control system described by a linearized model with Markovian switching. First, the evolution of sudden failures of the spacecraft’s actuators is described by a Markov process. Then, the mathematical model of the spacecraft attitude control system with the Markov jump characteristic fault is established. Taking the uncertainty of the system model and external interference into consideration, a fault-tolerant control scheme is proposed for the established spacecraft attitude control system with the Markov jump characteristic fault by using the sliding mode control technique. Compared with some existing sliding mode controller design methods, the proposed method requires a less total number of LMIs to be solved. The stability and reachability of the resulting closed-loop system under the presented sliding mode control scheme are proven by applying the Lyapunov stability theory. Finally, some simulation results are provided to show the effectiveness and advantages of the proposed control method for spacecraft attitude control.  相似文献   

9.
An adaptive dynamic programming controller based on backstepping method is designed for the optimal tracking control of hypersonic flight vehicles. The control input is divided into two parts namely stable control and optimal control. First, the back-stepping method is exploited via neural networks (NNs) to estimate unknown functions. Then, the computational load is reduced by the minimal-learning-parameter (MLP) scheme. To avoid the problem of “explosion of terms”, a first-order filter is adopted. Next, the optimal controller is designed based on the adaptive dynamic programming. In order to solve the Hamiltonian equation, NNs estimators are introduced to approximate performance indicators, achieving the approximate optimal control of hypersonic flight vehicles. Finally, the effectiveness and advantages of the control method are verified by simulation results.  相似文献   

10.
This article proposes a novel explicit-time and explicit-accuracy adaptive fuzzy control for a state-constrained nonlinear nonstrict-feedback uncertain system. This method can explicitly parameterize the upper bound of settling-time with low initial control input under a bounded initial condition. Meanwhile, this method can also explicitly parameterize the upper bound of accuracy while achieving low control input based on the adaptive fuzzy dynamic-approximation theorem. Firstly, a novel generalized explicit-time stability system is proposed by introducing the boundary gain term to render the time-parameter explicit, this method can solve the input conservatism problem caused by the unbounded-state gain term of traditional fixed/prdefined-time function. Then, according to the universal fuzzy approximation theorem, the novel dynamic relationship of adaptive fuzzy logic system between approximation error and adaptive parameters is presented. This relationship can lead to the adaptive fuzzy dynamic-approximation theorem, and an adaptive law designed by this theorem can realize the Lyapunov stability of adaptive control system under a Lasalle invariant set. In the end, a novel adaptive fuzzy control scheme is proposed by the generalized explicit-time function and adaptive fuzzy dynamic-approximation theorem. This scheme can achieve the explicit-time stability by the human-like activation function, and the accuracy can be parameterized by Lyapunov synthesis. Compared with other existing fixed/prdefined-time adaptive fuzzy control methods, the proposed explicit-time and explicit-accuracy controller achieves a significant reduction in the initial control input. Theoretical analysis and simulation results validate the effectiveness of the proposed method.  相似文献   

11.
A novel adaptive control with σ-modification for uncertain nonlinear systems is proposed in the paper. The application of conventional adaptive control is severely limited by the problems of construction of Lyapunov function and parameter drift because of non-parametric uncertainties. The proposed adaptive control that is on the basis of the immersion and invariance theory and σ-modification can be used to deal with these problems to some extent. It turns out to be a structured design method without requiring a Lyapunov function in the design level and robust to non-parametric uncertainties. Moreover, constrained command filter backstepping is adopted to meet the amplitude and rate constraints on the states and actuators. The uniformly ultimately bounded stability of the closed-loop system has been analyzed by Lyapunov theory with parametric and non-parametric uncertainties of the controlled model. To demonstrate the design flexibility, the method is applied to the position tracking control system design of a mass-damper-spring system and the flight control system design of a scramjet-powered air-breathing hypersonic vehicle. Finally, the effectiveness of the proposed adaptive control method is illustrated by numerical simulations.  相似文献   

12.
《Journal of The Franklin Institute》2022,359(18):11068-11088
The formation control problem with time-varying characteristics is investigated for the time-delayed nonlinear multi-agent systems against actuator attacks. A neural-network-based adaptive control method is constructed to achieve the desired control objective, which is outputs of the followers can complete the desired transformation of formation configuration. To eliminate the influence of malicious attacks on the actuators, an actuator attacks defense strategy is proposed to resist false data injection attacks occurred in the actuator. The uncertainty of the dynamics caused by nonlinear functions is resolved by the neural-network approximate method. The problem of the time delay is handled by an improved Lyapunov-Krasovskii functional approach, which can also avoid the singularity problem that may occur during the construction of the control method. Based on the Lyapunov stability theory, it is proved that all signals of closed-loop systems are semi-globally stable and the formation error can converge to a small neighborhood of the origin. Finally, the results of simulations are provided to verify the feasibility of the theoretical analysis and the effectiveness of the proposed control method.  相似文献   

13.
In this work, a new design method of model predictive control (MPC) is proposed for uncertain systems with input constraints. By using a new method to deal with actuator constraints, our method can reduce the conservativeness. For the design of the robust MPC controllers, a sequence of feedback control laws is used and a parameter-dependent Lyapunov function is chosen to further reduce the conservativeness. The effectiveness and performance of our MPC design method are demonstrated by an example.  相似文献   

14.
In this paper, a fixed-time dual closed-loop attitude control method is investigated for a quadrotor unmanned aerial vehicle. Firstly, a fixed-time adaptive fast super-twisting disturbance observer is presented for estimating the unknown external disturbance. A modified adaptive law is employed based on an equivalent control method to obtain proper observer gains. Secondly, a fixed-time controller is designed by using a universal barrier Lyapunov function to satisfy asymmetric tracking error constraints. Then, a tracking differentiator is utilised to arrange the transition process. Finally, the implementation of the developed method in a quadrotor unmanned aerial vehicle is performed. Through stability analysis and simulation results, the effectiveness and superiority of the proposed fixed-time control method are validated.  相似文献   

15.
This paper investigates the prescribed-time containment control problem for multi-agent systems with high-order nonlinear dynamics under a directed communication topology. Firstly, in view of the fact that only some follower agents can directly access the state information of multiple leader agents, a prescribed-time distributed observer is put forward to estimate the convex hull spanned by these leaders. Then, with the help of the distributed observer, a novel containment control method is developed for each follower based on a time-varying scaling function, so that all followers can converge to the convex hull spanned by the states of multiple leaders within a prescribed time. The comparison with the finite-time and fixed-time control methods differs in that the convergence time of the method proposed in this paper is independent of the initial conditions and control parameters and can be arbitrarily preassigned according to actual needs. Finally, an example is given to demonstrate the usefulness of the prescribed-time containment control method.  相似文献   

16.
基于线性二次型最优控制在结构振动控制中的研究   总被引：1，自引：0，他引：1  
动力设备在工作过程中引起的振动对设备运行的可靠性、安全性及周围环境都会产生重要影响,因此寻求抑制振动有效控制方法具有重要意义。本文介绍了线性二次型（LQR）最优控制方法,以三层振动体为研究对象,采用数值计算和仿真相结合的方法,分析探讨了线性二次型最优控制在振动控制中的明显优势。  相似文献   

17.
This article studies the neuroadaptive full-state constraints control problem for a class of electromagnetic active suspension systems (EASSs). First, the original constraint system with arbitrary initial values is transformed into a new constraint system with zero initial values by using the shift function method. Then, a new kind of cotangent-type nonlinear state-dependent transition function is constructed to solve the asymmetric time-varying full-state constraints control problem, which eliminates the limitation that the virtual controller needs to satisfy the feasibility conditions in the previous full-state constraints control based on Barrier Lyapunov Function (BLF) and Integral BLF. Furthermore, the neural networks (NNs) are used as nonlinear function approximators to deal with the unknown nonlinear dynamics of EASSs, a neuroadaptive full-state constraints control design method is proposed under the Backstepping recursive design framework. Finally, the effectiveness of the proposed method is verified by a simulation of EASSs with road disturbances.  相似文献   

18.
Traditional control method of air–fuel ratio (AFR) of aero engine cannot meet the performance requirement of fuel-powered unmanned aerial vehicle (UAV), which may lead to efficiency reduction and emission increase. In order to improve the control accuracy, this paper proposes a new AFR control method based on fuzzy-PID. We analyze the control results under different working conditions by using adaptive fuzzy-PID. Through simulation and experimental studies, we can draw the conclusions as follows: compared with PID control method, firstly, AFR control error can be reduced by 80% in normal condition; secondly, the control error is reduced by 55% in rapid acceleration condition; in addition, the control error can be reduced by 71% in continuous disturbance condition; comparison results with existing Fuzzy-PID also show that the improved controller has advantage in terms of resisting rapid and continuous interferences; moreover, in practical application of fuzzy-PID control, the highest AFR errors are about 3%. In normal condition, the error is reduced from 5 to 1% compared with PID control, which demonstrates the effectiveness of the improved fuzzy-PID control model. This research can be a reference in the application of UAV aero engine control.  相似文献   

19.
In this paper, the tracking control problem of uncertain Euler–Lagrange systems under control input saturation is studied. To handle system uncertainties, a leakage-type (LT) adaptive law is introduced to update the control gains to approach the disturbance variations without knowing the uncertainty upper bound a priori. In addition, an auxiliary dynamics is designed to deal with the saturation nonlinearity by introducing the auxiliary variables in the controller design. Lyapunov analysis verifies that based on the proposed method, the tracking error will be asymptotically bounded by a neighborhood around the origin. To demonstrate the proposed method, simulations are finally carried out on a two-link robot manipulator. Simulation results show that in the presence of actuator saturation, the proposed method induces less chattering signal in the control input compared to conventional sliding mode controllers.  相似文献   

20.
本文对航空发动机控制系统设计课程实验教学提出了新的建议和思考。随着国际先进航空发动机控制新技术的发展,基于快速原型的发动机控制系统以及系统综合控制规律设计方法已成为必然趋势,航空发动机控制系统设计专业教学必须做出适应性的对策与措施,以满足教学内容对专业发展需求。借助一些关键发动机仿真试验平台的建设,通过课程实验环节使得学生熟悉了解航空发动机控制系统设计新方法,是一条可行的航空发动机控制专业教学改革途径。  相似文献   

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