This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elim...This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power supply.This method effectively reduces the residual grounding current.To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was designed.An online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection locations.Furthermore,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time.Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults.Compared to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.展开更多
The mechanical horizontal platform(MHP)system exhibits a rich chaotic behavior.The chaotic MHP system has applications in the earthquake and offshore industries.This article proposes a robust adaptive continuous contr...The mechanical horizontal platform(MHP)system exhibits a rich chaotic behavior.The chaotic MHP system has applications in the earthquake and offshore industries.This article proposes a robust adaptive continuous control(RACC)algorithm.It investigates the control and synchronization of chaos in the uncertain MHP system with time-delay in the presence of unknown state-dependent and time-dependent disturbances.The closed-loop system contains most of the nonlinear terms that enhance the complexity of the dynamical system;it improves the efficiency of the closed-loop.The proposed RACC approach(a)accomplishes faster convergence of the perturbed state variables(synchronization errors)to the desired steady-state,(b)eradicates the effect of unknown state-dependent and time-dependent disturbances,and(c)suppresses undesirable chattering in the feedback control inputs.This paper describes a detailed closed-loop stability analysis based on the Lyapunov-Krasovskii functional theory and Lyapunov stability technique.It provides parameter adaptation laws that confirm the convergence of the uncertain parameters to some constant values.The computer simulation results endorse the theoretical findings and provide a comparative performance.展开更多
An adaptive control scheme is presented,which can simultaneously realize vibration suppression and compliance control for flexible joint robot(FJR).The proposed control scheme provides a unified formulation for both v...An adaptive control scheme is presented,which can simultaneously realize vibration suppression and compliance control for flexible joint robot(FJR).The proposed control scheme provides a unified formulation for both vibration suppression mode,where FJR tracks the desired position with little vibration,and compliance mode,in which FJR presents passive.Instead of designing multiple controllers and switching between them,both modes are integrated into a single controller,and the transition between two modes is smooth and stable.The stability of the closed-loop system is theoretically proven via the Lyapunov method,with the considering the dynamics uncertainties in both link side and motor side.Simulation results are presented to illustrate good performances of the proposed control scheme.展开更多
Aiming at the robustness issue in high-speed trains(HSTs)operation control,this article proposes a model-free adaptive control(MFAC)scheme to suppress disturbance.Firstly,the dynamic linearization data model of train ...Aiming at the robustness issue in high-speed trains(HSTs)operation control,this article proposes a model-free adaptive control(MFAC)scheme to suppress disturbance.Firstly,the dynamic linearization data model of train system under the action of measurement disturbance is given,and the Kalman filter(KF)based on this model is derived under the minimum variance estimation criterion.Then,according to the KF,an anti-interference MFAC scheme is designed.This scheme only needs the input and output data of the controlled system to realize the MFAC of the train under strong disturbance.Finally,the simulation experiment of CRH380A HSTs is carried out and compared with the traditional MFAC and the MFAC with attenuation factor.The proposed control algorithm can effectively suppress the measurement disturbance,and obtain smaller tracking error and larger signal to noise ratio with better applicability.展开更多
A DC grid based on half-bridge modular multilevel converters(HB-MMC)is a feasible means to realize the friendly grid connection of renewable energy.To solve problems such as the high cost and technical difficulty of D...A DC grid based on half-bridge modular multilevel converters(HB-MMC)is a feasible means to realize the friendly grid connection of renewable energy.To solve problems such as the high cost and technical difficulty of DC circuit breakers(DCCB),a coordinated control method for fault current suppression of DC grid connecting wind power is proposed.The key influencing factors of DC fault current are revealed by fault characteristics analysis,and an adaptive current-limiting control method for MMC is proposed,whose parameter selection principles are designed to ensure the safe operation of equipment while achieving effective suppression of fault current.In addition,a novel configuration method of dissipative resistors with the current-limiting function is proposed,which can solve the problem of surplus power in the DC grid and reduce the current stress of converter valves.Based on this,a coordination scheme of dissipative resistors,the adaptive current-limiting control method,and DCCBs are proposed to block fault current,effectively reducing the manufacturing difficulty and cost of DCCB.Finally,a four-terminal DC grid simulation model is built based on the RTLAB OP5600 real-time digital simulation platform,and the effectiveness and feasibility of the proposed methods are verified.展开更多
基金the Natural Science Foundation of Fujian,China(No.2021J01633).
文摘This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power supply.This method effectively reduces the residual grounding current.To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was designed.An online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection locations.Furthermore,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time.Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults.Compared to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.
文摘The mechanical horizontal platform(MHP)system exhibits a rich chaotic behavior.The chaotic MHP system has applications in the earthquake and offshore industries.This article proposes a robust adaptive continuous control(RACC)algorithm.It investigates the control and synchronization of chaos in the uncertain MHP system with time-delay in the presence of unknown state-dependent and time-dependent disturbances.The closed-loop system contains most of the nonlinear terms that enhance the complexity of the dynamical system;it improves the efficiency of the closed-loop.The proposed RACC approach(a)accomplishes faster convergence of the perturbed state variables(synchronization errors)to the desired steady-state,(b)eradicates the effect of unknown state-dependent and time-dependent disturbances,and(c)suppresses undesirable chattering in the feedback control inputs.This paper describes a detailed closed-loop stability analysis based on the Lyapunov-Krasovskii functional theory and Lyapunov stability technique.It provides parameter adaptation laws that confirm the convergence of the uncertain parameters to some constant values.The computer simulation results endorse the theoretical findings and provide a comparative performance.
基金supported by the National Key R&D Program of China(No.2017YFB1300400)the National Natural Science Foundation of China(No. 51805107)
文摘An adaptive control scheme is presented,which can simultaneously realize vibration suppression and compliance control for flexible joint robot(FJR).The proposed control scheme provides a unified formulation for both vibration suppression mode,where FJR tracks the desired position with little vibration,and compliance mode,in which FJR presents passive.Instead of designing multiple controllers and switching between them,both modes are integrated into a single controller,and the transition between two modes is smooth and stable.The stability of the closed-loop system is theoretically proven via the Lyapunov method,with the considering the dynamics uncertainties in both link side and motor side.Simulation results are presented to illustrate good performances of the proposed control scheme.
基金The authors thank the anonymous reviewers for their valuable suggestions.This work is supported by funds National Natural Science Foundation of China(Grants No.52162048,61991404 and 62003138)National Key Research and Development Program of China(Grant No.2020YFB1713703)Jiangxi Graduate Innovation Fund Project(Grant No.YC2021-S446).
文摘Aiming at the robustness issue in high-speed trains(HSTs)operation control,this article proposes a model-free adaptive control(MFAC)scheme to suppress disturbance.Firstly,the dynamic linearization data model of train system under the action of measurement disturbance is given,and the Kalman filter(KF)based on this model is derived under the minimum variance estimation criterion.Then,according to the KF,an anti-interference MFAC scheme is designed.This scheme only needs the input and output data of the controlled system to realize the MFAC of the train under strong disturbance.Finally,the simulation experiment of CRH380A HSTs is carried out and compared with the traditional MFAC and the MFAC with attenuation factor.The proposed control algorithm can effectively suppress the measurement disturbance,and obtain smaller tracking error and larger signal to noise ratio with better applicability.
基金supported in part by the National Natural Science Foundation of China under Grant 52207078in part by the Joint Funds of the National Natural Science Foundation of China under Grant U2066208.
文摘A DC grid based on half-bridge modular multilevel converters(HB-MMC)is a feasible means to realize the friendly grid connection of renewable energy.To solve problems such as the high cost and technical difficulty of DC circuit breakers(DCCB),a coordinated control method for fault current suppression of DC grid connecting wind power is proposed.The key influencing factors of DC fault current are revealed by fault characteristics analysis,and an adaptive current-limiting control method for MMC is proposed,whose parameter selection principles are designed to ensure the safe operation of equipment while achieving effective suppression of fault current.In addition,a novel configuration method of dissipative resistors with the current-limiting function is proposed,which can solve the problem of surplus power in the DC grid and reduce the current stress of converter valves.Based on this,a coordination scheme of dissipative resistors,the adaptive current-limiting control method,and DCCBs are proposed to block fault current,effectively reducing the manufacturing difficulty and cost of DCCB.Finally,a four-terminal DC grid simulation model is built based on the RTLAB OP5600 real-time digital simulation platform,and the effectiveness and feasibility of the proposed methods are verified.
