Optical skyrmions represent a novel frontier in topological optics with diverse generation methods emerging recently,offering significant potential for robust optical information processing,high-density data storage,a...Optical skyrmions represent a novel frontier in topological optics with diverse generation methods emerging recently,offering significant potential for robust optical information processing,high-density data storage,and other advanced photonic technologies.However,significant challenges persist in understanding their topological robustness under perturbations and in achieving flexible on-demand topologically controlled generation,both of which are essential for real-world applications.Here,we propose the theory of topological protection degrees to classify the robustness of the topological texture of optical skyrmions under perturbations,distinguishing between strong and weak protection.Then,we demonstrate the electrical generation of topologically tunable optical skyrmions through a controllable modulation scheme with common optical elements.Building upon this,we experimentally validate the proposed topological protection degrees under complex perturbations.Our work lays a foundational framework for future research on topological stability of optical skyrmions and paves the way for their applications in data transmission and storage.展开更多
This paper presents a comparative performance analysis of a new five-phase fault-tolerant flux-switching permanent-magnet(FT-FSPM)motor for high-reliability applications under the two most popular control schemes,name...This paper presents a comparative performance analysis of a new five-phase fault-tolerant flux-switching permanent-magnet(FT-FSPM)motor for high-reliability applications under the two most popular control schemes,namely,field-oriented control(FOC)and direct torque control(DTC)based on stator-flux orientation.Firstly,the new motor topology and structural characteristics are briefly presented.Secondly,the d-and q-axis for the FT-FSPM motor are defined,which is crucial to the mathematical model and control scheme,and the mathematical models are derived.Then,two control schemes,i.e.,FOC and DTC,and the main system are proposed.The operational principles of the two control schemes are presented,and space vector pulse width modulation(SVPWM)based on four neighboring vectors is adopted to reduce current harmonics and torque ripples.Finally,the simulated and experimental results are given,and performance analysis of the two control schemes are compared and discussed.The results reveal that FOC scheme has the sinusoidal phase current and low torque ripples,while the DTC scheme has fast dynamic response,verifying the effectiveness of the two proposed control schemes.This paper is a primary investigation for more possible improvements in the control schemes of the five-phase FS-FTPM motor.展开更多
基金National Natural Science Foundation of China(12174122)Natural Science Foundation of Guangdong Province(2022A1515011482,2024A1515010556)+2 种基金Singapore Ministry of Education(MOE)AcRF Tier 1 grants(RG157/23,RT11/23)Singapore Agency for Science,Technology and Research(A*STAR)MTC Individual Research Grants(M24N7c0080)Nanyang Assistant Professorship Start Up grant。
文摘Optical skyrmions represent a novel frontier in topological optics with diverse generation methods emerging recently,offering significant potential for robust optical information processing,high-density data storage,and other advanced photonic technologies.However,significant challenges persist in understanding their topological robustness under perturbations and in achieving flexible on-demand topologically controlled generation,both of which are essential for real-world applications.Here,we propose the theory of topological protection degrees to classify the robustness of the topological texture of optical skyrmions under perturbations,distinguishing between strong and weak protection.Then,we demonstrate the electrical generation of topologically tunable optical skyrmions through a controllable modulation scheme with common optical elements.Building upon this,we experimentally validate the proposed topological protection degrees under complex perturbations.Our work lays a foundational framework for future research on topological stability of optical skyrmions and paves the way for their applications in data transmission and storage.
基金Supported by Key Research and Development Program of Jiangsu Province under Grant BE2018107,Natural Science Foundation of Jiangsu Province under Grant BK20171298Natural Science Foundation of Jiangsu Higher Education Institutions under Grant 18KJB470008.
文摘This paper presents a comparative performance analysis of a new five-phase fault-tolerant flux-switching permanent-magnet(FT-FSPM)motor for high-reliability applications under the two most popular control schemes,namely,field-oriented control(FOC)and direct torque control(DTC)based on stator-flux orientation.Firstly,the new motor topology and structural characteristics are briefly presented.Secondly,the d-and q-axis for the FT-FSPM motor are defined,which is crucial to the mathematical model and control scheme,and the mathematical models are derived.Then,two control schemes,i.e.,FOC and DTC,and the main system are proposed.The operational principles of the two control schemes are presented,and space vector pulse width modulation(SVPWM)based on four neighboring vectors is adopted to reduce current harmonics and torque ripples.Finally,the simulated and experimental results are given,and performance analysis of the two control schemes are compared and discussed.The results reveal that FOC scheme has the sinusoidal phase current and low torque ripples,while the DTC scheme has fast dynamic response,verifying the effectiveness of the two proposed control schemes.This paper is a primary investigation for more possible improvements in the control schemes of the five-phase FS-FTPM motor.
