In bistaic acoustic testing, there will be strong direct blast interference. An algorithm based on signal phase-matching array processing that rejects direct blast interference in bistatic acoustic testing has been st...In bistaic acoustic testing, there will be strong direct blast interference. An algorithm based on signal phase-matching array processing that rejects direct blast interference in bistatic acoustic testing has been studied, through which the object scattering signal is accurately extracted. Characteristics of bistatic acoustic testing and signal phase matching processing principle are fully integrated in this algorithm. Firstly, the direct blast interference is calculated from the receiving signal based on three subarrays signal phase matching processing. Secondly, the direct blast is rejected by subtraction from the receiving signal. In this way the limitations of the high signal to noise ratio that signal phase matching processing required for direct calculating the object scattering signal can be avoided. Simulation and sea trial results show that, when the ratio of signal to interference is greater than -20 dB, this algorithm of direct blast interference rejection based phase matching signal processing can accurately extract the object scattering signal.展开更多
The equalization management system is an essential guarantee for the safe,stable,and efficient operation of the power battery pack,mainly composed of the topology of the equalization circuit and the corresponding cont...The equalization management system is an essential guarantee for the safe,stable,and efficient operation of the power battery pack,mainly composed of the topology of the equalization circuit and the corresponding control strategy.This article proposes a novel active balancing control strategy to address the issue of individual cell energy imbalance in battery packs.Firstly,to achieve energy equalization under complex conditions,a two-layer equalization circuit topology is designed,and the efficiency and loss of energy transfer in the equalization process are studied.Furthermore,a directed graph-based approach was proposed to represent the circuit topology equivalently as a multi-weighted network.Combined with a multi-weighted optimal matching algorithm,aims to determine the optimal energy transfer path and reduce equalization losses.In addition,a fuzzy controller that can dynamically adjust the equalization current with the state parameter of the cell as the input condition is designed to optimize the equalization efficiency.Matlab/Simulink software is used to build and simulate the model.The experimental results indicate that,under the same static state,the newly proposed control strategy improves efficiency by 6.08%and enhances equalization speed by 42.03%compared to the maximum value equalization method.The method also effectively improves energy utilization under the same charging and discharging states.展开更多
Alternating direction implicit finite difference time domain （ADI-FDTD） method is unconditionally stable and the maximum time step is not limited by the Courant stability condition, but rather by numerical error. Co...Alternating direction implicit finite difference time domain （ADI-FDTD） method is unconditionally stable and the maximum time step is not limited by the Courant stability condition, but rather by numerical error. Compared with the conventional FDTD method, the time step of ADI-FDTD can be enlarged arbitrarily and the CPU cost can be reduced. 2D perfectly matched layer （PML） absorbing boundary condition is proposed to truncate computation space for ADI-FDTD in dispersive media using recursive convolution（RC） method and the 2D PML formulations for dispersive media are derived. ADI-FDTD formulations for dispersive media can be obtained from the simplified PML formulations. The scattering of target in dispersive soil is simulated under sine wave and Gaussian pulse excitations and numerical results of ADI-FDTD with PML are compared with FDTD. Good agreement is observed. At the same time the CPU cost for ADI-FDTD is obviously reduced.展开更多
基金supported by the Foundation of Key Laboratory for Underwater Test & Control Technology under Grant No.9140C260201110C26
文摘In bistaic acoustic testing, there will be strong direct blast interference. An algorithm based on signal phase-matching array processing that rejects direct blast interference in bistatic acoustic testing has been studied, through which the object scattering signal is accurately extracted. Characteristics of bistatic acoustic testing and signal phase matching processing principle are fully integrated in this algorithm. Firstly, the direct blast interference is calculated from the receiving signal based on three subarrays signal phase matching processing. Secondly, the direct blast is rejected by subtraction from the receiving signal. In this way the limitations of the high signal to noise ratio that signal phase matching processing required for direct calculating the object scattering signal can be avoided. Simulation and sea trial results show that, when the ratio of signal to interference is greater than -20 dB, this algorithm of direct blast interference rejection based phase matching signal processing can accurately extract the object scattering signal.
基金supported by the Natural Science Foundation of Hebei Province(Grant No.F2023502011 and E2023502026)the Chongqing Natural Science Foundation(Grant No.CSTB2023NSCQMSX0359).
文摘The equalization management system is an essential guarantee for the safe,stable,and efficient operation of the power battery pack,mainly composed of the topology of the equalization circuit and the corresponding control strategy.This article proposes a novel active balancing control strategy to address the issue of individual cell energy imbalance in battery packs.Firstly,to achieve energy equalization under complex conditions,a two-layer equalization circuit topology is designed,and the efficiency and loss of energy transfer in the equalization process are studied.Furthermore,a directed graph-based approach was proposed to represent the circuit topology equivalently as a multi-weighted network.Combined with a multi-weighted optimal matching algorithm,aims to determine the optimal energy transfer path and reduce equalization losses.In addition,a fuzzy controller that can dynamically adjust the equalization current with the state parameter of the cell as the input condition is designed to optimize the equalization efficiency.Matlab/Simulink software is used to build and simulate the model.The experimental results indicate that,under the same static state,the newly proposed control strategy improves efficiency by 6.08%and enhances equalization speed by 42.03%compared to the maximum value equalization method.The method also effectively improves energy utilization under the same charging and discharging states.
文摘Alternating direction implicit finite difference time domain （ADI-FDTD） method is unconditionally stable and the maximum time step is not limited by the Courant stability condition, but rather by numerical error. Compared with the conventional FDTD method, the time step of ADI-FDTD can be enlarged arbitrarily and the CPU cost can be reduced. 2D perfectly matched layer （PML） absorbing boundary condition is proposed to truncate computation space for ADI-FDTD in dispersive media using recursive convolution（RC） method and the 2D PML formulations for dispersive media are derived. ADI-FDTD formulations for dispersive media can be obtained from the simplified PML formulations. The scattering of target in dispersive soil is simulated under sine wave and Gaussian pulse excitations and numerical results of ADI-FDTD with PML are compared with FDTD. Good agreement is observed. At the same time the CPU cost for ADI-FDTD is obviously reduced.
