This paper is concerned with the estimation problem for discrete-time stochastic linear systems with possible single unit delay and multiple packet dropouts. Based on a proposed uncertain model in data transmission, a...This paper is concerned with the estimation problem for discrete-time stochastic linear systems with possible single unit delay and multiple packet dropouts. Based on a proposed uncertain model in data transmission, an optimal full-order filter for the state of the system is presented, which is shown to be of the form of employing the received outputs at the current and last time instants. The solution to the optimal filter is given in terms of a Riccati difference equation governed by two binary random variables. The optimal filter is reduced to the standard Kalman filter when there are no random delays and packet dropouts. The steady-state filter is also investigated. A sufficient condition for the existence of the steady-state filter is given. The asymptotic stability of the optimal filter is analyzed.展开更多
This paper addresses the problem of distributed secondary control for islanded AC microgrids with external disturbances.By using a full-order sliding-mode(FOSM)approach,voltage regulation and frequency restoration are...This paper addresses the problem of distributed secondary control for islanded AC microgrids with external disturbances.By using a full-order sliding-mode(FOSM)approach,voltage regulation and frequency restoration are achieved in finite time.For voltage regulation,a distributed observer is proposed for each distributed generator(DG)to estimate a reference voltage level.Different from some conventional observers,the reference voltage level in this paper is accurately estimated under directed communication topologies.Based on the observer,a new nonlinear controller is designed in a backstepping manner such that an FOSM surface is reached in finite time.On the surface,the voltages of DGs are regulated to the reference level in finite time.For frequency restoration,a distributed controller is further proposed such that a constructed FOSM surface is reached in finite time,on which the frequencies of DGs are restored to a reference level in finite time under directed communication topologies.Finally,case studies on a modified IEEE 37-bus test system are conducted to demonstrate the effectiveness,the robustness against load changes,and the plug-and-play capability of the proposed controllers.展开更多
A parametric approach to robust fault detection in linear systems with unknown disturbances is presented. The residual is generated using full-order state observers (FSO). Based on an analytical solution to a type o...A parametric approach to robust fault detection in linear systems with unknown disturbances is presented. The residual is generated using full-order state observers (FSO). Based on an analytical solution to a type of Sylvester matrix equations, the parameterization of the observer gain matrix is given. In terms of the design degrees of freedom provided by the parametric observer design and a group of introduced parameter vectors, a sufficient and necessary condition for fullorder state observer design with disturbance decoupling is then established. By properly constraining the design parameters according to this proposed condition, the effect of the disturbance on the residual signal is also decoupled, and a simple algorithm is developed. The presented approach offers all the degrees of design freedom. Finally, a numerical example illustrates the effect of the proposed approach.展开更多
In this paper, a full-order observer which can be fully decoupled from the unknown inputs as the conventional full-order observer does is designed by using auxiliary outputs, but the requirement of the matching condit...In this paper, a full-order observer which can be fully decoupled from the unknown inputs as the conventional full-order observer does is designed by using auxiliary outputs, but the requirement of the matching condition is removed. The procedure of calculating the parameter matrices of the full-order observer is also presented. Compared with the existing auxiliary outputs based sliding-mode observers, the designed observer has a simpler design procedure, which is systematic and does not involve solving linear matrix inequalities. The simulation results show that the proposed method is effective.展开更多
In this paper, a full-order sliding mode control based on extended state observer(FSMC+ESO) is proposed for high-order nonlinear system with unknown system states and uncertainties.The extended state observer(ESO) is ...In this paper, a full-order sliding mode control based on extended state observer(FSMC+ESO) is proposed for high-order nonlinear system with unknown system states and uncertainties.The extended state observer(ESO) is employed to estimate both the unknown system states and uncertainties so that the restriction that the system states should be completely measurable is relaxed,and a full-order sliding mode controller is designed based on the ESO estimation to overcome the chattering problem existing in ordinary reduced-order sliding mode control. Simulation results show that the proposed method facilitates the practical application with respect to good tracking performance and chattering elimination.展开更多
在“双碳”背景下,风电作为零碳电力和新能源发电的主力军,在助力社会全面绿色低碳转型方面发挥了关键性作用。在保证发电稳定的前提下实现风能的最大化利用,提升风力发电系统发电量至为重要。文中针对永磁同一步风力发电系统的最大功...在“双碳”背景下,风电作为零碳电力和新能源发电的主力军,在助力社会全面绿色低碳转型方面发挥了关键性作用。在保证发电稳定的前提下实现风能的最大化利用,提升风力发电系统发电量至为重要。文中针对永磁同一步风力发电系统的最大功率跟踪(maximum power point tracking, MPPT)问题进行研究。首先建立了永磁同步风力发电系统的机理仿真模型,用两电平双PWM全功率换流器连接风力发电机与电网。然后基于以上模型,分别设计了整数阶PI控制器、分数阶PI"控制器、模糊分数阶PP控制器以实现MPPT控制。最后对以上控制策略进行了仿真研究。结果表明,无论在阶跃风速还是随机风速下,模糊分数阶PU控制器相较于其他两种均具有更出色的MPPT性能与更强的鲁棒性。展开更多
文中以三端口柔性多状态开关(soft open point,SOP)为研究对象,建立考虑参数摄动的SOP数学模型,并基于虚拟控制技术,提出一种全阶滑模控制方法以增强系统的抗干扰能力。母线电压控制系统由母线电压与电流两个反馈回路构成,其控制器均采...文中以三端口柔性多状态开关(soft open point,SOP)为研究对象,建立考虑参数摄动的SOP数学模型,并基于虚拟控制技术,提出一种全阶滑模控制方法以增强系统的抗干扰能力。母线电压控制系统由母线电压与电流两个反馈回路构成,其控制器均采用全阶滑模(full-order sliding-mode,FOSM)控制方法设计以增强系统的动态性能和对参数摄动的鲁棒性。基于虚拟控制技术设计的外环控制器能完全补偿由参数摄动引起的非匹配不确定性干扰,设计的积分型控制律完全消除了滑模抖振,保证电流给定信号完全平滑。有功功率与无功功率控制器设计均采用全阶终端滑模(full-order terminal sliding mode,FOTSM),保证目标功率精确跟踪的同时,减小了输出功率脉动。最后,在MATLAB/Simulink中搭建三端口SOP的仿真模型,仿真结果验证了在SOP系统参数摄动情况下所提控制算法的有效性和优越性。展开更多
基金supported by Agency for Science,Technology and Research Grant(SERC)(No.0521010037)Natural Science Foundation of China(No.60874062,60828006)NSFC-Guangdong Joint Foundation(No.U0735003)
文摘This paper is concerned with the estimation problem for discrete-time stochastic linear systems with possible single unit delay and multiple packet dropouts. Based on a proposed uncertain model in data transmission, an optimal full-order filter for the state of the system is presented, which is shown to be of the form of employing the received outputs at the current and last time instants. The solution to the optimal filter is given in terms of a Riccati difference equation governed by two binary random variables. The optimal filter is reduced to the standard Kalman filter when there are no random delays and packet dropouts. The steady-state filter is also investigated. A sufficient condition for the existence of the steady-state filter is given. The asymptotic stability of the optimal filter is analyzed.
基金supported in part by the Australian Research Council Discovery Project(DP160103567)the program of Jiangsu Specially-Appointed Professor(RK043STP19001)+1 种基金the fund of high-level talents at NJUPT(XK0430919039)the fund of scientific and technological innovation projects for overseas students in Nanjing(RK043NLX19004)。
文摘This paper addresses the problem of distributed secondary control for islanded AC microgrids with external disturbances.By using a full-order sliding-mode(FOSM)approach,voltage regulation and frequency restoration are achieved in finite time.For voltage regulation,a distributed observer is proposed for each distributed generator(DG)to estimate a reference voltage level.Different from some conventional observers,the reference voltage level in this paper is accurately estimated under directed communication topologies.Based on the observer,a new nonlinear controller is designed in a backstepping manner such that an FOSM surface is reached in finite time.On the surface,the voltages of DGs are regulated to the reference level in finite time.For frequency restoration,a distributed controller is further proposed such that a constructed FOSM surface is reached in finite time,on which the frequencies of DGs are restored to a reference level in finite time under directed communication topologies.Finally,case studies on a modified IEEE 37-bus test system are conducted to demonstrate the effectiveness,the robustness against load changes,and the plug-and-play capability of the proposed controllers.
基金This work was supported by the National Natural Science Foundation of China (No. 60374024)the Program for Changjiang Scholars andInnovative Research Team in University.
文摘A parametric approach to robust fault detection in linear systems with unknown disturbances is presented. The residual is generated using full-order state observers (FSO). Based on an analytical solution to a type of Sylvester matrix equations, the parameterization of the observer gain matrix is given. In terms of the design degrees of freedom provided by the parametric observer design and a group of introduced parameter vectors, a sufficient and necessary condition for fullorder state observer design with disturbance decoupling is then established. By properly constraining the design parameters according to this proposed condition, the effect of the disturbance on the residual signal is also decoupled, and a simple algorithm is developed. The presented approach offers all the degrees of design freedom. Finally, a numerical example illustrates the effect of the proposed approach.
基金Supported by the National Natural Science Foundation of China(No.61203299)
文摘In this paper, a full-order observer which can be fully decoupled from the unknown inputs as the conventional full-order observer does is designed by using auxiliary outputs, but the requirement of the matching condition is removed. The procedure of calculating the parameter matrices of the full-order observer is also presented. Compared with the existing auxiliary outputs based sliding-mode observers, the designed observer has a simpler design procedure, which is systematic and does not involve solving linear matrix inequalities. The simulation results show that the proposed method is effective.
基金supported by the National Natural Science Foundation of China under Grant No.61403343the China Postdoctoral Science Foundation funded project under Grant No.2015M580521
文摘In this paper, a full-order sliding mode control based on extended state observer(FSMC+ESO) is proposed for high-order nonlinear system with unknown system states and uncertainties.The extended state observer(ESO) is employed to estimate both the unknown system states and uncertainties so that the restriction that the system states should be completely measurable is relaxed,and a full-order sliding mode controller is designed based on the ESO estimation to overcome the chattering problem existing in ordinary reduced-order sliding mode control. Simulation results show that the proposed method facilitates the practical application with respect to good tracking performance and chattering elimination.
文摘在“双碳”背景下,风电作为零碳电力和新能源发电的主力军,在助力社会全面绿色低碳转型方面发挥了关键性作用。在保证发电稳定的前提下实现风能的最大化利用,提升风力发电系统发电量至为重要。文中针对永磁同一步风力发电系统的最大功率跟踪(maximum power point tracking, MPPT)问题进行研究。首先建立了永磁同步风力发电系统的机理仿真模型,用两电平双PWM全功率换流器连接风力发电机与电网。然后基于以上模型,分别设计了整数阶PI控制器、分数阶PI"控制器、模糊分数阶PP控制器以实现MPPT控制。最后对以上控制策略进行了仿真研究。结果表明,无论在阶跃风速还是随机风速下,模糊分数阶PU控制器相较于其他两种均具有更出色的MPPT性能与更强的鲁棒性。