Uneven power distribution,transient voltage,and frequency deviations are observed in the photovoltaic storage hybrid inverter during the switching between grid-connected and island modes.In response to these issues,th...Uneven power distribution,transient voltage,and frequency deviations are observed in the photovoltaic storage hybrid inverter during the switching between grid-connected and island modes.In response to these issues,this paper proposes a grid-connected/island switching control strategy for photovoltaic storage hybrid inverters based on the modified chimpanzee optimization algorithm.The proposed strategy incorporates coupling compensation and power differentiation elements based on the traditional droop control.Then,it combines the angular frequency and voltage amplitude adjustments provided by the phase-locked loop-free pre-synchronization control strategy.Precise pre-synchronization is achieved by regulating the virtual current to zero and aligning the photovoltaic storage hybrid inverter with the grid voltage.Additionally,two novel operators,learning and emotional behaviors are introduced to enhance the optimization precision of the chimpanzee algorithm.These operators ensure high-precision and high-reliability optimization of the droop control parameters for photovoltaic storage hybrid inverters.A Simulink model was constructed for simulation analysis,which validated the optimized control strategy’s ability to evenly distribute power under load transients.This strategy effectively mitigated transient voltage and current surges during mode transitions.Consequently,seamless and efficient switching between gridconnected and island modes was achieved for the photovoltaic storage hybrid inverter.The enhanced energy utilization efficiency,in turn,offers robust technical support for grid stability.展开更多
To solve the problem of large positioning error and discontinuous positioning of special forces members when moving in cross-region indoors and outdoors, and to compensate for the linearization error and local converg...To solve the problem of large positioning error and discontinuous positioning of special forces members when moving in cross-region indoors and outdoors, and to compensate for the linearization error and local convergence problem that may exist in the extended Kalman filter(EKF)in nonlinear systems, that is,the iterative results may be trapped in a local optimum situation, a seamless indoor-outdoor switching localization algorithm based on cubature Kalman filter (CKF) is proposed. CKF does not require the computation of Jacobian matrices, which can improve computational efficiency and filtering accuracy to a certain extent. In the system, an inertial measurement unit (IMU) is employed to correct the positioning errors of ultra-wideband (UWB)and BeiDou navigation satellite system(BDS).The positioning data from UWB and BeiDou in cross-region are weighted fused and then fused with the data from the IMU using CKF to obtain the final accurate positioning information. This study designs a scene-switching mechanism to achieve seamless switching between indoor and outdoor positioning scenes. By jointly analyzing the positioning accuracy of UWB and BeiDou,the positioning scene is determined, and appropriate counting thresholds are set to avoid frequent erroneous scene switches. Experimental results show that the proposed algorithm achieves a positioning accuracy of approximately 21.7 cm in cross-region,which can enable seamless integration of indoor and outdoor positioning,avoid positioning jumps, and enhance positioning accuracy.展开更多
With the rapid development of renewable energy,power system inertia is gradually decreasing,threatening the stability of system frequency.Grid-forming(GF)-based wind turbines(WTs)equipped with active inertia response ...With the rapid development of renewable energy,power system inertia is gradually decreasing,threatening the stability of system frequency.Grid-forming(GF)-based wind turbines(WTs)equipped with active inertia response are key to addressing the problem of low-inertia power systems.However,existing researches have focused on the inertia response of GF-based WTs in the maximum power point tracking(MPPT)range,while lacking the discussion on the control and implementation of inertia response in other operating ranges.Therefore,this paper proposes an inertia response control method for permanent magnet synchronous generator(PMSG)-based WTs across the full wind speed range based on inertia synchronization control(IsynC).By analyzing the characteristics of the inertia response and safe operating boundaries of the WT at different operational stages,a control method for the smooth speed transition of the WT across different operating ranges is proposed.By utilizing a composite judgment logic based on the DC voltage rate of change and rotor speed,an adaptive inertia response for different operating modes is achieved.Single and multiple PMSG-WT simulation models are built in PSCAD/EMTDC to simulate the proposed full wind speed range inertia response control and its operational characteristics.The results demonstrate that this method enables the selective inertia response of WTs across the full wind speed range,effectively enhancing the frequency support capabilities of renewable energy generation systems.展开更多
The multi-port energy router(ER)is an effective topology for integrating train traction load,AC load,the energy storage system and photovoltaic(PV)energy.The start and stop process of urban rail transit trains and the...The multi-port energy router(ER)is an effective topology for integrating train traction load,AC load,the energy storage system and photovoltaic(PV)energy.The start and stop process of urban rail transit trains and the access of distributed energy sources to rail transit ER lead to serious fluctuations of DC bus power,so it is necessary to route energy between different ports,involving multi-operating modes,while seamless switching is a major challenge.In this paper,a hierarchical coordinated control strategy is proposed to enable the multi-port ER to operate in a coor-dinated fashion under the conditions of train parking,acceleration,constant power driving and deceleration,and to switch seamlessly under various working conditions.The energy central dispatching layer sends working condi-tion instructions by sampling the state information of each port,while the microgrid control layer adopts central-ized control,receiving upper working condition instructions and sending drive signals to the local control layers to maintain the balanced energy flow of each port.In the local control layers,the PV adopts the improved perturbation and observation method of power control(PC-P&O),while the ES system adopts voltage loop control with an SOC influence factor,voltage loop control with switching factor and power loop control according to the different working conditions,so as to transmit the required train load power accurately and maintain the stability of the DC bus voltage.Finally,the effectiveness of the proposed hierarchical coordination control is verified by MATLAB/Simulink simulations.展开更多
The Tianwen-1 probe,used in China’s first Mars exploration mission,features multiple flight phases,numerous spatial pointing constraints,and complex working modes.During the braking and capture process,it faces chall...The Tianwen-1 probe,used in China’s first Mars exploration mission,features multiple flight phases,numerous spatial pointing constraints,and complex working modes.During the braking and capture process,it faces challenges such as uplink or downlink command delay,unique capture window,post-control“occultation”,short-time significant change in speed increment,and interference caused by low-frequency and low-damping solid–liquid flexible coupling oscillations.Therefore,high reliability,high autonomy,and high precision are required for the braking and capture process.As the executor of braking and capture control,the GNC(guidance,navigation,and control)subsystem of the orbiter employs an online orbit control strategy reconstruction method based on arc loss compensation to realize high reliability,the main engine anomaly recognition and a seamless switching scheme to realize high autonomy,and the attitude–orbit coupling control algorithm with thrust direction compensation to realize high-precision speed increment control.According to the on-orbit flight validation of the Tianwen-1 probe,the GNC subsystem of the orbiter has completed the braking and capture control task reliably and autonomously with millimeter-per-second-level accuracy,effectively ensuring the successful execution of subsequent landing and patrol tasks.This paper analyzes the online orbit control strategy reconstruction method,anomaly recognition and seamless switching method,and thrust vector control method of the braking and capture process and offers valuable insights for future interplanetary exploration flight control.展开更多
基金received funding from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_1633)2023 University Student Innovation and Entrepreneurship Training Program(202311463009Z)+1 种基金Changzhou Science and Technology Support Project(CE20235045)Open Project of Jiangsu Key Laboratory of Power Transmission&Distribution Equipment Technology(2021JSSPD12).
文摘Uneven power distribution,transient voltage,and frequency deviations are observed in the photovoltaic storage hybrid inverter during the switching between grid-connected and island modes.In response to these issues,this paper proposes a grid-connected/island switching control strategy for photovoltaic storage hybrid inverters based on the modified chimpanzee optimization algorithm.The proposed strategy incorporates coupling compensation and power differentiation elements based on the traditional droop control.Then,it combines the angular frequency and voltage amplitude adjustments provided by the phase-locked loop-free pre-synchronization control strategy.Precise pre-synchronization is achieved by regulating the virtual current to zero and aligning the photovoltaic storage hybrid inverter with the grid voltage.Additionally,two novel operators,learning and emotional behaviors are introduced to enhance the optimization precision of the chimpanzee algorithm.These operators ensure high-precision and high-reliability optimization of the droop control parameters for photovoltaic storage hybrid inverters.A Simulink model was constructed for simulation analysis,which validated the optimized control strategy’s ability to evenly distribute power under load transients.This strategy effectively mitigated transient voltage and current surges during mode transitions.Consequently,seamless and efficient switching between gridconnected and island modes was achieved for the photovoltaic storage hybrid inverter.The enhanced energy utilization efficiency,in turn,offers robust technical support for grid stability.
基金supported by the Shaanxi Provincial Key Research and Development Program under Grant 2021GY-022.
文摘To solve the problem of large positioning error and discontinuous positioning of special forces members when moving in cross-region indoors and outdoors, and to compensate for the linearization error and local convergence problem that may exist in the extended Kalman filter(EKF)in nonlinear systems, that is,the iterative results may be trapped in a local optimum situation, a seamless indoor-outdoor switching localization algorithm based on cubature Kalman filter (CKF) is proposed. CKF does not require the computation of Jacobian matrices, which can improve computational efficiency and filtering accuracy to a certain extent. In the system, an inertial measurement unit (IMU) is employed to correct the positioning errors of ultra-wideband (UWB)and BeiDou navigation satellite system(BDS).The positioning data from UWB and BeiDou in cross-region are weighted fused and then fused with the data from the IMU using CKF to obtain the final accurate positioning information. This study designs a scene-switching mechanism to achieve seamless switching between indoor and outdoor positioning scenes. By jointly analyzing the positioning accuracy of UWB and BeiDou,the positioning scene is determined, and appropriate counting thresholds are set to avoid frequent erroneous scene switches. Experimental results show that the proposed algorithm achieves a positioning accuracy of approximately 21.7 cm in cross-region,which can enable seamless integration of indoor and outdoor positioning,avoid positioning jumps, and enhance positioning accuracy.
基金supported in part by the National Key R&D Program of China(No.2022YFB2402703).
文摘With the rapid development of renewable energy,power system inertia is gradually decreasing,threatening the stability of system frequency.Grid-forming(GF)-based wind turbines(WTs)equipped with active inertia response are key to addressing the problem of low-inertia power systems.However,existing researches have focused on the inertia response of GF-based WTs in the maximum power point tracking(MPPT)range,while lacking the discussion on the control and implementation of inertia response in other operating ranges.Therefore,this paper proposes an inertia response control method for permanent magnet synchronous generator(PMSG)-based WTs across the full wind speed range based on inertia synchronization control(IsynC).By analyzing the characteristics of the inertia response and safe operating boundaries of the WT at different operational stages,a control method for the smooth speed transition of the WT across different operating ranges is proposed.By utilizing a composite judgment logic based on the DC voltage rate of change and rotor speed,an adaptive inertia response for different operating modes is achieved.Single and multiple PMSG-WT simulation models are built in PSCAD/EMTDC to simulate the proposed full wind speed range inertia response control and its operational characteristics.The results demonstrate that this method enables the selective inertia response of WTs across the full wind speed range,effectively enhancing the frequency support capabilities of renewable energy generation systems.
基金supported by the Chinese National Natural Science Foundation (grant number 51977039 and 51950410593).
文摘The multi-port energy router(ER)is an effective topology for integrating train traction load,AC load,the energy storage system and photovoltaic(PV)energy.The start and stop process of urban rail transit trains and the access of distributed energy sources to rail transit ER lead to serious fluctuations of DC bus power,so it is necessary to route energy between different ports,involving multi-operating modes,while seamless switching is a major challenge.In this paper,a hierarchical coordinated control strategy is proposed to enable the multi-port ER to operate in a coor-dinated fashion under the conditions of train parking,acceleration,constant power driving and deceleration,and to switch seamlessly under various working conditions.The energy central dispatching layer sends working condi-tion instructions by sampling the state information of each port,while the microgrid control layer adopts central-ized control,receiving upper working condition instructions and sending drive signals to the local control layers to maintain the balanced energy flow of each port.In the local control layers,the PV adopts the improved perturbation and observation method of power control(PC-P&O),while the ES system adopts voltage loop control with an SOC influence factor,voltage loop control with switching factor and power loop control according to the different working conditions,so as to transmit the required train load power accurately and maintain the stability of the DC bus voltage.Finally,the effectiveness of the proposed hierarchical coordination control is verified by MATLAB/Simulink simulations.
基金supported by the National Natural Science Foundation of China(Grant No.11672126).
文摘The Tianwen-1 probe,used in China’s first Mars exploration mission,features multiple flight phases,numerous spatial pointing constraints,and complex working modes.During the braking and capture process,it faces challenges such as uplink or downlink command delay,unique capture window,post-control“occultation”,short-time significant change in speed increment,and interference caused by low-frequency and low-damping solid–liquid flexible coupling oscillations.Therefore,high reliability,high autonomy,and high precision are required for the braking and capture process.As the executor of braking and capture control,the GNC(guidance,navigation,and control)subsystem of the orbiter employs an online orbit control strategy reconstruction method based on arc loss compensation to realize high reliability,the main engine anomaly recognition and a seamless switching scheme to realize high autonomy,and the attitude–orbit coupling control algorithm with thrust direction compensation to realize high-precision speed increment control.According to the on-orbit flight validation of the Tianwen-1 probe,the GNC subsystem of the orbiter has completed the braking and capture control task reliably and autonomously with millimeter-per-second-level accuracy,effectively ensuring the successful execution of subsequent landing and patrol tasks.This paper analyzes the online orbit control strategy reconstruction method,anomaly recognition and seamless switching method,and thrust vector control method of the braking and capture process and offers valuable insights for future interplanetary exploration flight control.
