Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound so...Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given.展开更多
Battery energy storage systems bolster power grids’absorption capacity,however,battery safety issues remain a formidable challenge.Timely and pre-cise fault diagnosis,coupled with early-stage fault warn-ings,is cruci...Battery energy storage systems bolster power grids’absorption capacity,however,battery safety issues remain a formidable challenge.Timely and pre-cise fault diagnosis,coupled with early-stage fault warn-ings,is crucial.This study introduces an eigen decompo-sition-based multi-fault diagnosis approach for lithi-umion battery packs,enabling online diagnosis of short circuits,electrical connection faults,and voltage sensor malfunctions.By incorporating an interleaved measurement topology,precise fault type differentiation is achieved.Eigenvector matching analysis is employed to increase sensitivity to fault characteristics and enhance robustness.The interleaved topology can be seamlessly integrated using common voltage measurement solutions,eliminating the need for additional design complexities,while sensor number redundancy enhances fault tolerance of battery management systems(BMS).A cloud-side collaboration method is proposed,where the BMS functions as an edge device for specific data computations,while the parameters are fine-tuned by the server through big data analytics.This approach circumvents cumbersome server calculations,thereby curbing server cost escalation.The edge computing process is divided into two steps,with partial calculations often sufficient to evaluate battery safety,thus reducing the computational load on edge devices.Several battery tests are conducted,and the results confirm the method’s capability,feasibility,and validity in early-stage fault diagnosis.展开更多
A new quasi-orthogonal space-time block code （QO-STBC） scheme, based on eigen value decomposition （EVD）, is explored in this paper. The new scheme can significantly reduce the QO-STBC decoding complexity at receiv...A new quasi-orthogonal space-time block code （QO-STBC） scheme, based on eigen value decomposition （EVD）, is explored in this paper. The new scheme can significantly reduce the QO-STBC decoding complexity at receiver and achieves better bit-error rate （BER） performance as well. With EVD manipulations, the detection matrix and the channel matrix can be redefined to remove all interference terms which come from other antennas, and therefore the conventional maximum likelihood （ML） decoding method with less complexity can be applied. Moreover the new scheme improves the BER performance significantly. Theoretical analysis and simulation results are presented in this paper to show the validation of this new scheme.展开更多
文摘Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given.
基金supported in part by the National Natural Science Foundation of China(No.62133007)Shandong Provincial Key Research and Development Program(No.2024CXPT052).
文摘Battery energy storage systems bolster power grids’absorption capacity,however,battery safety issues remain a formidable challenge.Timely and pre-cise fault diagnosis,coupled with early-stage fault warn-ings,is crucial.This study introduces an eigen decompo-sition-based multi-fault diagnosis approach for lithi-umion battery packs,enabling online diagnosis of short circuits,electrical connection faults,and voltage sensor malfunctions.By incorporating an interleaved measurement topology,precise fault type differentiation is achieved.Eigenvector matching analysis is employed to increase sensitivity to fault characteristics and enhance robustness.The interleaved topology can be seamlessly integrated using common voltage measurement solutions,eliminating the need for additional design complexities,while sensor number redundancy enhances fault tolerance of battery management systems(BMS).A cloud-side collaboration method is proposed,where the BMS functions as an edge device for specific data computations,while the parameters are fine-tuned by the server through big data analytics.This approach circumvents cumbersome server calculations,thereby curbing server cost escalation.The edge computing process is divided into two steps,with partial calculations often sufficient to evaluate battery safety,thus reducing the computational load on edge devices.Several battery tests are conducted,and the results confirm the method’s capability,feasibility,and validity in early-stage fault diagnosis.
文摘A new quasi-orthogonal space-time block code （QO-STBC） scheme, based on eigen value decomposition （EVD）, is explored in this paper. The new scheme can significantly reduce the QO-STBC decoding complexity at receiver and achieves better bit-error rate （BER） performance as well. With EVD manipulations, the detection matrix and the channel matrix can be redefined to remove all interference terms which come from other antennas, and therefore the conventional maximum likelihood （ML） decoding method with less complexity can be applied. Moreover the new scheme improves the BER performance significantly. Theoretical analysis and simulation results are presented in this paper to show the validation of this new scheme.
