In the context of induction motor control, there are various control strategies used to separately control torque and flux. One common approach is known as Field-Oriented Control (FOC). This technique involves transfo...In the context of induction motor control, there are various control strategies used to separately control torque and flux. One common approach is known as Field-Oriented Control (FOC). This technique involves transforming the three-phase currents and voltages into a rotating reference frame, commonly referred to as the “dq” frame. In this frame, the torque/speed and flux components are decoupled, allowing for independent control, by doing so, the motor’s speed can be regulated accurately and maintain a constant flux which is crucial to ensure optimal motor performance and efficiency. The research focused on studying and simulating a field-oriented control system using fuzzy control techniques for an induction motor. The aim was to address the issue of parameter variations, particularly the change in rotor resistance during motor operation, which causes the control system to deviate from the desired direction. This deviation implies to an increase in the magnetic flux value, specifically the flux component on the q-axis. By employing fuzzy logic techniques to regulate flux vector’s components in the dq frame, this problem was successfully resolved, ensuring that the magnetic flux value remains within the nominal limits. To enhance the control system’s performance, response speed, and efficiency of the motor, sliding mode controllers were implemented to regulate the current in the inner loop. The simulation results demonstrated the proficiency of the proposed methodology.展开更多
The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlle...The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.展开更多
Cylindrical vector beams and vortex beams,two types of typical singular optical beams characterized by axially symmetric polarization and helical phase front,possess the unique focusing property and the ability of car...Cylindrical vector beams and vortex beams,two types of typical singular optical beams characterized by axially symmetric polarization and helical phase front,possess the unique focusing property and the ability of carrying orbital angular momentum.We discuss the formation mechanisms of such singular beams in few-mode fibers under the vortex basis and show recent advances in generating techniques that are mainly based on long-period fiber gratings,mode-selective couplers,offset-spliced fibers,and tapered fibers.The performances of cylindrical vector beams and vortex beams generated in fibers and fiber lasers are summarized and compared to give a comprehensive understanding of singular beams and to promote their practical applications.展开更多
Published online:14 August 2023 A matrix-vector multiplication(MVM)optical signal processor based on mode division multiplexing(MDM)was proposed and demon-strated in the current work,which is composed of a mode multip...Published online:14 August 2023 A matrix-vector multiplication(MVM)optical signal processor based on mode division multiplexing(MDM)was proposed and demon-strated in the current work,which is composed of a mode multiplexer,a multimode beam splitter,a mode demultiplexer,a modulator ar-ray and combiners.In addition,the characteristics of MDM obviate the need for multiple wavelengths and therefore multiple laser light sources are unneeded,which greatly reduces the complexity and cost.A 4×4 MDM-MVM was realized on a standard silicon-on-insulator(SOI)platform.Combined with the off-chip light source and photode-tectors(PDs),4-level modulation has been demonstrated,and each level of the output signal could represent 2 bits of information.展开更多
Rabi oscillations express a phenomenon of periodic conversion between two wave states in a coupled system.The finding of Rabi oscillation has led to important applications in many different disciplines.Despite great p...Rabi oscillations express a phenomenon of periodic conversion between two wave states in a coupled system.The finding of Rabi oscillation has led to important applications in many different disciplines.Despite great progress,it is still unknown whether the Rabi oscillating state can be excited in the framework of the higher-order vector vortex regime.Here,we demonstrate in theory that the higher-order vector vortex light beams can be Rabi oscillating during evolution in an optical coupling system.This new classical oscillating state of light is characterized by a topologically shaped wavefront and coupled with spatially varying polarization.The vector vortex state exhibits a harmonic oscillatory property in the resonant and nonresonant conditions but differs greatly in Rabi oscillating frequencies.During Rabi oscillation,the complex state maintains its topology and intensity profile,while its intrinsic polarization pattern varies adiabatically in a periodic manner.We present an interpretation of the Rabi oscillation of the higher-order wave states in terms of the coupled-mode theory.Furthermore,we reveal a symmetry-protected transition between two Rabi oscillating modes,driven by a slowly varying phase mismatch.This Rabi transition has not been reported in either quantum mechanics or any other physical setting.This work advances the research of Rabi oscillation into the higher-order regime,and it may lead to novel applications in classical and quantum optics.展开更多
文摘In the context of induction motor control, there are various control strategies used to separately control torque and flux. One common approach is known as Field-Oriented Control (FOC). This technique involves transforming the three-phase currents and voltages into a rotating reference frame, commonly referred to as the “dq” frame. In this frame, the torque/speed and flux components are decoupled, allowing for independent control, by doing so, the motor’s speed can be regulated accurately and maintain a constant flux which is crucial to ensure optimal motor performance and efficiency. The research focused on studying and simulating a field-oriented control system using fuzzy control techniques for an induction motor. The aim was to address the issue of parameter variations, particularly the change in rotor resistance during motor operation, which causes the control system to deviate from the desired direction. This deviation implies to an increase in the magnetic flux value, specifically the flux component on the q-axis. By employing fuzzy logic techniques to regulate flux vector’s components in the dq frame, this problem was successfully resolved, ensuring that the magnetic flux value remains within the nominal limits. To enhance the control system’s performance, response speed, and efficiency of the motor, sliding mode controllers were implemented to regulate the current in the inner loop. The simulation results demonstrated the proficiency of the proposed methodology.
基金supported by the National Natural Science Foundation of China(62073019)。
文摘The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.
基金This work was supported by the National Key R&D Program of China(2017YFA0303800)the National Natural Science Foundation of China(11874300,11634010,61575162,61805277,61675169,91950207)+1 种基金the Fundamental Research Funds for the Central Universities(3102017AX009,3102019PY002,3102019JC008)the Natural Science Basic Research Program of Shaanxi(2018JM6013,2019JQ-447).
文摘Cylindrical vector beams and vortex beams,two types of typical singular optical beams characterized by axially symmetric polarization and helical phase front,possess the unique focusing property and the ability of carrying orbital angular momentum.We discuss the formation mechanisms of such singular beams in few-mode fibers under the vortex basis and show recent advances in generating techniques that are mainly based on long-period fiber gratings,mode-selective couplers,offset-spliced fibers,and tapered fibers.The performances of cylindrical vector beams and vortex beams generated in fibers and fiber lasers are summarized and compared to give a comprehensive understanding of singular beams and to promote their practical applications.
基金supported by National Major Research and Devel-opment Program(2021YFB2801703)National Natural Science Foundation of China(62135011&62105286)+1 种基金“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C01103)the Fundamental Research Funds for the Central Universities.
文摘Published online:14 August 2023 A matrix-vector multiplication(MVM)optical signal processor based on mode division multiplexing(MDM)was proposed and demon-strated in the current work,which is composed of a mode multiplexer,a multimode beam splitter,a mode demultiplexer,a modulator ar-ray and combiners.In addition,the characteristics of MDM obviate the need for multiple wavelengths and therefore multiple laser light sources are unneeded,which greatly reduces the complexity and cost.A 4×4 MDM-MVM was realized on a standard silicon-on-insulator(SOI)platform.Combined with the off-chip light source and photode-tectors(PDs),4-level modulation has been demonstrated,and each level of the output signal could represent 2 bits of information.
基金National Natural Science Foundation of China(11974146 and 62175091)Guangzhou Municipal Science and Technology Project(201904010094)+1 种基金Key-Area Research and Development Program of Guangdong Province(2020B090922006)the Pearl River talent project(2017GC010280).
文摘Rabi oscillations express a phenomenon of periodic conversion between two wave states in a coupled system.The finding of Rabi oscillation has led to important applications in many different disciplines.Despite great progress,it is still unknown whether the Rabi oscillating state can be excited in the framework of the higher-order vector vortex regime.Here,we demonstrate in theory that the higher-order vector vortex light beams can be Rabi oscillating during evolution in an optical coupling system.This new classical oscillating state of light is characterized by a topologically shaped wavefront and coupled with spatially varying polarization.The vector vortex state exhibits a harmonic oscillatory property in the resonant and nonresonant conditions but differs greatly in Rabi oscillating frequencies.During Rabi oscillation,the complex state maintains its topology and intensity profile,while its intrinsic polarization pattern varies adiabatically in a periodic manner.We present an interpretation of the Rabi oscillation of the higher-order wave states in terms of the coupled-mode theory.Furthermore,we reveal a symmetry-protected transition between two Rabi oscillating modes,driven by a slowly varying phase mismatch.This Rabi transition has not been reported in either quantum mechanics or any other physical setting.This work advances the research of Rabi oscillation into the higher-order regime,and it may lead to novel applications in classical and quantum optics.
