Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of tw...Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.展开更多
This paper proposes a comprehensive design scheme for the extremum seeking control(ESC)of the unmanned aerial vehicle(UAV)close formation flight.The proposed design scheme combines a Newton-Raphson method with an exte...This paper proposes a comprehensive design scheme for the extremum seeking control(ESC)of the unmanned aerial vehicle(UAV)close formation flight.The proposed design scheme combines a Newton-Raphson method with an extended Kalman filter(EKF)to dynamically estimate the optimal position of the following UAV relative to the leading UAV.To reflect the wake vortex effects reliably,the drag coefficient induced by the wake vortex is considered as a performance function.Then,the performance function is parameterized by the first-order and second-order terms of its Taylor series expansion.Given the excellent performance of nonlinear estimation,the EKF is used to estimate the gradient and the Hessian matrix of the parameterized performance function.The output feedback of the proposed scheme is determined by iterative calculation of the Newton-Raphson method.Compared with the traditional ESC and the classic ESC,the proposed design scheme avoids the slow continuous time integration of the gradient.This allows a faster convergence of relative position extremum.Furthermore,the proposed method can provide a smoother command during the seeking process as the second-order term of the performance function is taken into account.The convergence analysis of the proposed design scheme is accomplished by showing that the output feedback is a supermartingale sequence.To improve estimation performance of the EKF,a improved pigeon-inspired optimization(IPIO)is proposed to automatically tune the noise covariance matrix.Monte Carlo simulations for a three-UAV close formation show that the proposed design scheme is robust to the initial position of the following UAV.展开更多
The suppression of combustion instabilities using the extremum seeking algorithm(ESA) is analyzed.A function model of the pressure oscillation and the mean fuel–air ratio in the combustion chamber is derived and impl...The suppression of combustion instabilities using the extremum seeking algorithm(ESA) is analyzed.A function model of the pressure oscillation and the mean fuel–air ratio in the combustion chamber is derived and implies an extremum relation between the oscillation amplitude of the pressure and the mean fuel–air ratio.Hence, the control system of combustion instabilities can be considered as an extremum seeking control system(ESCS). All traditional ESCSs employ a separate design method, which divides the design of the ESA from the controller design. It is thus difficult for traditional ESCSs to achieve optimal performance of the control system. To solve this problem, an integrated extremum seeking control method for ESCSs is proposed. Using this integrated control, the minimal oscillation amplitude of the pressure is realized by adaptively seeking the optimal mean fuel–air ratio. Hence, this design method can effectively suppress combustion instabilities in aeroengines. By comparing simulation results, the effectiveness of the proposed method is validated.展开更多
针对极值搜索控制系统(Extremum seeking control systems,ESCSs)设计中,极值搜索算法与控制器采取单独设计时易导致系统难以发挥其最佳性能,而现有的一体化设计方法却存在需要根据被控对象和具体的极值搜索算法进行不同形式的一体化建...针对极值搜索控制系统(Extremum seeking control systems,ESCSs)设计中,极值搜索算法与控制器采取单独设计时易导致系统难以发挥其最佳性能,而现有的一体化设计方法却存在需要根据被控对象和具体的极值搜索算法进行不同形式的一体化建模的问题,以块控型的极值搜索控制系统为研究对象,提出了一套通用的极值搜索控制系统的一体化控制方法.首先针对块控型极值搜索控制系统,采用反馈线性化设计思想,构建出系统的伪虚拟控制量;然后以极值搜索算法得到的搜索变量作为其输入量,设计多层神经网络(Multilayer neural networks,MNNs)逼近由近似模型与实际模型之间的差异而导致的误差项、状态变量的极值和极值的变化率,同时运用自适应参数和鲁棒项函数抵消神经网络逼近误差的影响;最后利用反演控制方法求取出系统的虚拟控制量和实际控制量.此一体化控制方法确保系统的状态跟踪误差、输出量与其极值之间的误差、极值搜索变量的跟踪误差以及神经网络各参数的估计误差均有界且指数收敛至系统原点的一个有限邻域内,且理论分析和仿真结果都验证了此方法的有效性.展开更多
文摘Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.
基金supported by the National Natural Science Foundation of China(Grant Nos.91948204,U20B2071,T2121003 and U1913602)Open Fund/Postdoctoral Fund of the Laboratory of Cognition and Decision Intelligence for Complex Systems,Institute of Automation,Chinese Academy of Sciences(Grant No.CASIA-KFKT-08)。
文摘This paper proposes a comprehensive design scheme for the extremum seeking control(ESC)of the unmanned aerial vehicle(UAV)close formation flight.The proposed design scheme combines a Newton-Raphson method with an extended Kalman filter(EKF)to dynamically estimate the optimal position of the following UAV relative to the leading UAV.To reflect the wake vortex effects reliably,the drag coefficient induced by the wake vortex is considered as a performance function.Then,the performance function is parameterized by the first-order and second-order terms of its Taylor series expansion.Given the excellent performance of nonlinear estimation,the EKF is used to estimate the gradient and the Hessian matrix of the parameterized performance function.The output feedback of the proposed scheme is determined by iterative calculation of the Newton-Raphson method.Compared with the traditional ESC and the classic ESC,the proposed design scheme avoids the slow continuous time integration of the gradient.This allows a faster convergence of relative position extremum.Furthermore,the proposed method can provide a smoother command during the seeking process as the second-order term of the performance function is taken into account.The convergence analysis of the proposed design scheme is accomplished by showing that the output feedback is a supermartingale sequence.To improve estimation performance of the EKF,a improved pigeon-inspired optimization(IPIO)is proposed to automatically tune the noise covariance matrix.Monte Carlo simulations for a three-UAV close formation show that the proposed design scheme is robust to the initial position of the following UAV.
基金supported by the National Natural Science Foundation of China(60674090)
文摘The suppression of combustion instabilities using the extremum seeking algorithm(ESA) is analyzed.A function model of the pressure oscillation and the mean fuel–air ratio in the combustion chamber is derived and implies an extremum relation between the oscillation amplitude of the pressure and the mean fuel–air ratio.Hence, the control system of combustion instabilities can be considered as an extremum seeking control system(ESCS). All traditional ESCSs employ a separate design method, which divides the design of the ESA from the controller design. It is thus difficult for traditional ESCSs to achieve optimal performance of the control system. To solve this problem, an integrated extremum seeking control method for ESCSs is proposed. Using this integrated control, the minimal oscillation amplitude of the pressure is realized by adaptively seeking the optimal mean fuel–air ratio. Hence, this design method can effectively suppress combustion instabilities in aeroengines. By comparing simulation results, the effectiveness of the proposed method is validated.
