With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling an...With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling and mode switching analysis of EHA used in the primary flight control actuation systems of large aircraft,addressing the challenges associated with mode switching.First,we analyze the functional architecture and operational characteristics of multi-mode EHA,and sumarize the operating modes and implementation methods.Based on the EHA system architecture,we then develop a theoretical mathematical model and a simulation model.Using the simulation model,we analyze the performance of the EHA during normal operation.Finally,the performance of the EHA during mode switching under various functional switching scenarios is investigated.The results indicate that the EHA meets the performance requirements in terms of accuracy,bandwidth,and load capacity.Additionally,the hydraulic cylinder operates smoothly during the EHA mode switching,and the response time for switching between different modes is less than the specified threshold.These findings validate the system performance of multi-mode EHA,which helps to improve the reliability of EHA and the safety of aircraft flight control systems.展开更多
In order to enhance the safety of autonomous driving vehicles,this work focuses on the issue of automatic-to-manual mode transition in the column electric power steering(C-EPS)system.First,we utilized an extended stat...In order to enhance the safety of autonomous driving vehicles,this work focuses on the issue of automatic-to-manual mode transition in the column electric power steering(C-EPS)system.First,we utilized an extended state observer to estimate the driver's steering torque and designed a steering mode transition unit.Second,we validated the mode switching function through an experimental platform.The results indicated that when using the extended state observer for torque estimation,the steering wheel angle and lower input angle errors were approximately±0.5%.The input and observed torque curves were closely aligned,demonstrating excellent tracking capability of the system.In addition,by adopting a steering mode conversion unit,the switch from autonomous control to manual control has been obtained,achieving a smooth and minimal change in steering wheel angle without significant bumps.The experimental results demonstrate that the designed mode switching strategy has the advantages of speed and smoothness,and has strong practical value.展开更多
The photovoltaic(PV)output process is inherently complex,often disrupted by a multitude of meteoro-logical factors,while conventional detection methods at PV power stations prove inadequate,compromising prediction acc...The photovoltaic(PV)output process is inherently complex,often disrupted by a multitude of meteoro-logical factors,while conventional detection methods at PV power stations prove inadequate,compromising prediction accuracy.To address this challenge,this paper introduces a power prediction method that leverages modal switching(MS),weight factor adjustment(WFA),and parallel long short-term memory(PALSTM).Initially,historical PV power station data is categorized into distinct modes based on global horizontal irradiance and converted solar angles.Correlation analysis is then employed to evaluate the impact of various meteorological factors on PV power,selecting those with strong correlations for each specific mode.Subsequently,the weights of meteorological parameters are optimized and adjusted,and a PALSTM neural network is constructed,with its parallel modal parameters refined through training.Depending on the prediction time and input data mode characteristics,the appropriate mode channel is selected to forecast PV power station generation.Ultimately,the feasibility of this method is validated through an illustrative analysis of measured data from an Australian PV power station.Comparative test results underscore the method’s advantages,particularly in scenarios where existing detection methods are lacking and meteorological factors frequently fluctuate,demonstrating its superior prediction accuracy and stability.展开更多
Based on analyzing the structure and working principle on electric vehicles （EVs） with dual motors coupled by planetarY gears, the control strategy of mode switching was proposed. The power interruption problem on E...Based on analyzing the structure and working principle on electric vehicles （EVs） with dual motors coupled by planetarY gears, the control strategy of mode switching was proposed. The power interruption problem on EVs with automatic mechanical transmission （AMT） shifting was resolved. Based on the speed-torque characteristics of the planetary gears and the principle of the auxiliary motor＇ s zero speed braking, control features of mode switching were introduced. The mode shifting between the main motor mode and dual motors coupled driving were studied. Matlab/Simulink was adopted as a platform to develop the simulation model of EVs with dual motors drive system and 3 gears AMT. Simulation results demonstrated that the power interruption of dual motors drive system was solved during mode switching. The power requirements of EVs were satisfied, too.展开更多
The control strategy is firstly the first braking power according to the fuzzy control algorithm, considering the speed, the battery SOC and the battery maximum charging power limit to obtain the maximum braking speed...The control strategy is firstly the first braking power according to the fuzzy control algorithm, considering the speed, the battery SOC and the battery maximum charging power limit to obtain the maximum braking speed, thus the secondary distribution of the hydraulic braking torque. Then the brake control strategy can reduce the impact of the EV braking mode conversion process, and meet the braking demand and brake safety, which proves the effectiveness of the control strategy. In order to ensure the braking stability of the vehicle and further improve the energy utilization rate of electric vehicles, the vehicle speed refueling controller, battery charging state and braking force are used as the energy variables, and the braking force distribution coefficient is taken as the output variable. The braking power distribution coefficient is recommended, considering the stability requirements of the engine, battery, and braking system, to distribute mechanical braking and engine regeneration to the front and rear axles of the machine. Simulation of the developed regenerative braking strategy is analyzed and incorporated into the AVL cruise park model. The results show that this strategy improves braking stability and comfort over the classical ECE curve control strategy, increasing FTP75 by 17.22% compared to the classical ECE curve control strategy展开更多
Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typi...Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typical DC distribution network with multiple voltage levels is considered as a research object.It is proposed that the interface converters between DC buses with different voltage levels be implemented through the series-parallel combination of full-bridge LLC resonant converters.To realize the decentralized self-discipline control of DC voltage under various working conditions,different slack buses are prepared according to the voltage ranges of the DC buses,and the voltage regulation modes of the DC distribution network are divided into main voltage regulation mode,backup voltage regulation mode,and off-grid voltage droop regulation mode.By introducing a voltage coefficient related to DC voltage deviation as a basis for mode switching,the voltage fluctuations caused by slow switching between control modes in the method of traditional voltage margin control is reduced,facilitating fast and smooth switching between different voltage regulation modes.Finally,a simulation model for DC distribution networks is constructed utilizing MATLAB/Simulink.Simulation results verify the effectiveness and feasibility of the proposed voltage regulation modes and switching methods for DC distribution networks.Finally,an experimental platform is also constructed to verify the feasibility of the mode switching method proposed in this paper.展开更多
Industrial parks(IPs)play a crucial role in facilitating economic efficiency and comprehensive energy utilization in the industrial age.At the same time,multi-energy coupling and management of various types of energy ...Industrial parks(IPs)play a crucial role in facilitating economic efficiency and comprehensive energy utilization in the industrial age.At the same time,multi-energy coupling and management of various types of energy in IP have become serious challenges.In this paper,combined heat and power unit(CHP)model considering operation mode switching characteristics is formulated by exploring its internal composition to improve output flexibility of the energy supply side.Then,heat and electricity integrated energy system(HE-IES)optimal dispatch and pricing model are established,taking electricity and heat demand response strategy and steam thermal inertia property into account.Based on the above models,a mixed-integer bilinear programming framework is designed to coordinate the day-ahead operation and pricing strategy of the HE-IES in the IP.The scenario study is carried out on a practical industrial park in Southern China.Numerical results indicate the proposed mechanism can effectively improve IP’s energy utilization and economic efficiency.展开更多
The power split hybrid electric vehicle(HEV)adopts a power coupling configuration featuring dual planetary gearsets and multiple clutches,enabling diverse operational modes through clutch engagement and disengagement....The power split hybrid electric vehicle(HEV)adopts a power coupling configuration featuring dual planetary gearsets and multiple clutches,enabling diverse operational modes through clutch engagement and disengagement.The multi-clutch configuration usually involves the collaboration of two clutches during the transient mode switching process,thereby substantially elevating control complexity.This study focuses on power split HEVs that integrate multi-clutch mechanisms and investigates how different clutch collaboration manners impact the characteristics of transient mode switching.The powertrain model for the power-split HEV is established utilizing matrix-based methodologies.Through the formulation of clutch torque curves and clutch collaboration models,this research systematically explores the effects of clutch engagement timing and the duration of clutch slipping state on transient mode switching behaviors.Building upon this analysis,an optimization problem for control parameters pertaining to the two collaborative clutches is formulated.The simulated annealing algorithm is employed to optimize these control parameters.Simulation results demonstrate that the clutch collaboration manners have a great influence on the transient mode switching performance.Compared with the pre-calibrated benchmark and the optimal solution derived by the genetic algorithm,the maximal longitudinal jerk and clutch slipping work during the transient mode switching process is reduced obviously with the optimal control parameters derived by the simulated annealing algorithm.The study provides valuable insights for the dynamic coordinated control of the power-split HEVs featuring complex clutch collaboration mechanisms.展开更多
The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque d...The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque distribution is established under different working conditions to improve vehicle power and lateral stability.The anticipated demand torque is initially determined based on the structural characteristics and operational principles of the plant protection machine.Subsequently,a hierarchical control framework is devised by incorporating a formulated switching control strategy.Finally,a simulation model for torque distribution control strategy between shafts is developed on the Matlab/Simulink platform,followed by simulation and experimental verification.The results are presented as follows:the inter-shaft torque distribution strategy established in this paper increases the average longitudinal acceleration by 0.13 m/s^(2) and 0.14 m/s^(2) under the control of low and high to low adhesion road surfaces,respectively.Under the control of the single-line shifting condition,the yaw velocity can successfully follow the expected value with a maximum value of 0.61 rad/s.The side deflection angle of the center of mass does not exceed 2.8°,which can follow the ideal trajectory and improve power and safety.展开更多
We report the observation of electric field induced random lasing in a dye doped liquid crystal system. This was achieved by using a liquid crystal host with negative dielectric anisotropy doped with laser dye PM 597 ...We report the observation of electric field induced random lasing in a dye doped liquid crystal system. This was achieved by using a liquid crystal host with negative dielectric anisotropy doped with laser dye PM 597 in a 75 μm cell with a homeotropic alignment layer. In the absence of an applied field, only amplified spontaneous emission was observed since the liquid crystal orientation was uniform. However, application of a field resulted in a fieldinduced planar-like configuration with local nonuniformity in liquid crystal orientation. This led to random lasing in the energized state(voltage greater than a transition threshold). The onset of lasing occurs by application of either a spatially homogenous or a spatially inhomogeneous electric field across the liquid crystal. The characteristics of the emission spectra as a function of different(i) dye concentration and(ii) applied voltage were investigated using nanosecond pulsed laser excitation at 532 nm. The effects of using an inhomogeneous field were compared to the use of a homogenous field and reported. It is shown that the spatial configuration can be used to alter the emission spectra of the system. The work is used to suggest a new configuration, referred to here as"reverse mode," for liquid crystal-based random lasers. This new configuration may provide additional avenues for their use in commercial devices.展开更多
Mode-division multiplexing technology has been proposed as a crucial technique for enhancing communication capacity and alleviating growing communication demands.Optical switching,which is an essential component of op...Mode-division multiplexing technology has been proposed as a crucial technique for enhancing communication capacity and alleviating growing communication demands.Optical switching,which is an essential component of optical communication systems,enables information exchange between channels.However,existing optical switching solutions are inadequate for addressing flexible information exchange among the mode channels.In this study,we introduced a flexible mode switching system in a multimode fibre based on an optical neural network chip.This system utilised the flexibility of on-chip optical neural networks along with an all-fibre orbital angular momentum(OAM)mode multiplexer-demultiplexer to achieve mode switching among the three OAM modes within a multimode fibre.The system adopted an improved gradient descent algorithm to achieve training for arbitrary 3×3 exchange matrices and ensured maximum crosstalk of less than-18.7 dB,thus enabling arbitrary inter-mode channel information exchange.The proposed optical-neural-network-based mode-switching system was experimentally validated by successfully transmitting different modulation formats across various modes.This innovative solution holds promise for providing effective optical switching in practical multimode communication networks.展开更多
Electric-hydraulic hybrid power steering(E-HHPS)system,a novel device with multiple modes for commercial electric vehicles,is designed to realize both superior steering feel and high energy efficiency.However,inconsis...Electric-hydraulic hybrid power steering(E-HHPS)system,a novel device with multiple modes for commercial electric vehicles,is designed to realize both superior steering feel and high energy efficiency.However,inconsistent steering perfor-mance occurs in the mode-switching process due to different dynamic characteristics of electric and hydraulic components,which even threatens driving safety.In this paper,mode-switching strategy and dynamic compensation control method are proposed for the E-HHPS system to eliminate the inconsistency of steering feel,which comprehensively considers ideal assistance characteristics and energy consumption of the system.Then,the influence of disturbances on system stability is analyzed,and H_(∞)robust controller is employed to guarantee system robustness and stability.The experimental results dem-onstrate that the proposed strategy can provide a steering system with natural steering feel without apparent inconsistency and effectively minimize energy consumption.展开更多
This paper explores and proposes a design solution of an integrated skip cycle mode （SCM） control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V proces...This paper explores and proposes a design solution of an integrated skip cycle mode （SCM） control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V process. In order to meet the requirement of a wide temperature range and high yields of products, the schematic extracted from the layout is simulated with five process corners at 27℃ and 90℃. Simulation results demonstrate that the proposed integrated circuit is immune to noise and achieves skipping cycle control when switching mode power supply （SMPS） works with low load or without load.展开更多
To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot(ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of...To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot(ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of the legarm chain. When the robot performs a task, reconfigurable configuration and mode switching can be achieved using this joint. In contrast from traditional quadruped robots, this robot can stack in a designated area to optimize the occupied volume in a nonworking state. Kinematics modeling and dynamics modeling are established to evaluate the mechanical properties for multiple modes. All working modes of the robot are classified, which can be defined as deployable mode, locomotion mode and operation mode. Based on the stability margin and mechanical modeling, switching analysis and evaluation between each mode is carried out. Finally, the prototype experimental results verify the function realization and switching stability of multimode and provide a design method to integrate and perform multimode for quadruped robots with deployable characteristics.展开更多
The chattering characteristic of sliding mode control isanalyzed when it is applied in distributed control systems （DCSs）.For a DCS with random time delay and packet dropout, a discreteswitching system model with ti...The chattering characteristic of sliding mode control isanalyzed when it is applied in distributed control systems （DCSs）.For a DCS with random time delay and packet dropout, a discreteswitching system model with time varying sampling period isconstructed based on the time delay system method. The reachinglaw based sliding mode controller is applied in the proposedsystem. The exponential stability condition in the form of linearmatrix inequality is figured out based on the multi-Lyaponov functionmethod. Then, the chattering characteristic is analyzed for theswitching system, and a chattering region related with time varyingsampling period and external disturbance is proposed. Finally, numericalexamples are given to illustrate the validity of the analysisresult.展开更多
A power train dynamics model of a coaxial parallel hybrid electric vehicle （HEV） was built for different clutch operating states. With the state vector constituted by the motor rotation speed and the clutch transmit...A power train dynamics model of a coaxial parallel hybrid electric vehicle （HEV） was built for different clutch operating states. With the state vector constituted by the motor rotation speed and the clutch transmitting torque at two successive time steps, a discrete state space model for estimating the clutch transmitting torque was built, and the Kalman filtering algorithm was used to estimate the clutch transmitting torque. The Matlab/Simulink was employed to simulate the clutch transmitting torque for two mode-switch processes. Estimation errors were analyzed through compa- ring the estimated and simulated values of the clutch torque. Impact of the noise covariance and the sample time on clutch torque estimation errors were explored. The results show that the developed estimation method can be used to estimate the clutch transmitting torque for HEV with good accura- cy. The results are useful for torque direct control of automatic diaphragm clutches.展开更多
At present,solar thermal power generation is in the demonstration stage,and the large-scale production is affected by many factors.In view of the characteristics of different operating modes of photothermal power gene...At present,solar thermal power generation is in the demonstration stage,and the large-scale production is affected by many factors.In view of the characteristics of different operating modes of photothermal power generation,it is analyzed that the turbine needs to be started and stopped frequently due to different operating modes,which will lead to the instability of the output energy and the reduction of power generation efficiency.In this paper,the dynamic equation of energy conversion process is established by using the law of conservation of energy and conservation of mass.Combined with the logic switching criterion of the system,the system model was established by using the extended differential Petri net,and the validity and accuracy of the model were verified.Through the Petri net model of the system,the system’s working mode switching and power generation situation are analyzed due to the difference of direct normal irradiation intensity(DNI).Finally,the accuracy of the model is proved by comparing it with experimental data of the photovoltaic and thermal demonstration projects that have been connected to the grid.展开更多
An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liqu...An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liquid ratios(Q_(g)/Q_(l))and mixture velocities(vm)are non-intrusively and simultaneously captured by high-speed cameras.Both the in-plane and out-of-plane responses of the catenary riser are excited in all considered cases.The slug flow characteristics,including translational velocities,slug lengths,recurrence frequencies,and pressure variations,are analyzed and dis-cussed,as are the dynamic responses of the riser in terms of the amplitudes,space-varying frequency,and modal weight.The dominant modal response based on the root-mean-square amplitude profiles does not match that based on the dominant frequency.Three mode switching types are identified based on the RMS amplitude profiles and the dominant frequency.When vm is small,no mode switching(NMS)is observed in either the in-plane or out-of-plane responses.For mode switching I(MS I),the switching between the first and second modes in the in-plane response is induced by slug flow with different recurrence frequencies in cases of large Q_(g)/Q_(l).However,there is no mode switching in the out-of-plane response.The switching between the first and third modes for the in-plane response and the second and fourth modes for the out-of-plane response(MS II)occurs in cases of relatively high vm and low Q_(g)/Q_(l).展开更多
In order to realize the modular design of the microgrid,this paper proposed a new modular topology for the AC-DC mixed microgrid.In that topology,the AC microgrid unit and the DC microgrid unit were packaged together ...In order to realize the modular design of the microgrid,this paper proposed a new modular topology for the AC-DC mixed microgrid.In that topology,the AC microgrid unit and the DC microgrid unit were packaged together by the back-to-back converter.The battery-supercapacitor hybrid energy storage system was connected to the DC bus of back-to-back converter.By the reasonable design on the battery-supercapacitor hybrid system,the energy storage system could supply the rapid power and energy support for the microgrid spontaneously.The mathematical model and the control algorithm of that microgrid topology were studied.By the simulation analysis,it can be concluded that AC-DC mixed modular microgrid topology could operate steadily on both the grid-connected mode and the isolated mode.Furthermore,we can conclude by the simulation that the designed modular microgrid could operate uninterrupted when the microgrid topology switched from the grid-connected mode to the isolated mode.The seamless switching became the natural property for the modular microgrid.As a result,the modular microgrid topology can be considered as a usual power/load module to realize the friendly power interaction with the power grid.展开更多
Plasmonic metasurfaces,featuring broadband nonlinear optical responses and exceptional light-field manipulation capabilities,facilitate the passive Q-switching and mode-locking operation of a laser resonator as a satu...Plasmonic metasurfaces,featuring broadband nonlinear optical responses and exceptional light-field manipulation capabilities,facilitate the passive Q-switching and mode-locking operation of a laser resonator as a saturable absorber(SA)and thus enable the generation of short-and ultrashort pulses.Here,for the first time,to our knowledge,we successfully fabricate a transmission-type mid-infrared plasmonic metasurface SA composed of gold nanostructures on the fluoride substrate,leveraging localized resonance enhancement.Its nonlinear optical(NLO)properties are characterized by a home-made~2.78μm pulsed Z-scan system,demonstrating a remarkable modulation depth of up to 30%.By integrating the plasmonic metasurface SA into a simple linear-cavity Er:ZBLAN fiber laser,stable Q-switched mode-locking(QML)operation is achieved with a maximum average output power of 224 mW at 2.78μm.The output exhibits a Q-switched envelope of 768 ns containing mode-locking pulses with 51.42 ps duration at the fundamental repetition rate of 24.5 MHz.This work further expands the application of plasmonic metasurface SAs to the mid-IR wavelength region,by utilizing their enhanced NLO responses and tailored spectral characteristics,enabling them as a core component for next-generation mid-IR ultrafast lasers.展开更多
基金supported by the Chinese Civil Aircraft Project(No.MJ-2017-S49).
文摘With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling and mode switching analysis of EHA used in the primary flight control actuation systems of large aircraft,addressing the challenges associated with mode switching.First,we analyze the functional architecture and operational characteristics of multi-mode EHA,and sumarize the operating modes and implementation methods.Based on the EHA system architecture,we then develop a theoretical mathematical model and a simulation model.Using the simulation model,we analyze the performance of the EHA during normal operation.Finally,the performance of the EHA during mode switching under various functional switching scenarios is investigated.The results indicate that the EHA meets the performance requirements in terms of accuracy,bandwidth,and load capacity.Additionally,the hydraulic cylinder operates smoothly during the EHA mode switching,and the response time for switching between different modes is less than the specified threshold.These findings validate the system performance of multi-mode EHA,which helps to improve the reliability of EHA and the safety of aircraft flight control systems.
基金Supported by the National Natural Science Foundation of China(52172324)Key Research and Development Plan of Shaanxi Province(2021GY-285,2021SF-483)+1 种基金Science and Technology Project of Shaanxi Provincial Department of Transport(21-20K,20-38T)Fundamental Research Funds for the Central Universities,CHD(300102323501)。
文摘In order to enhance the safety of autonomous driving vehicles,this work focuses on the issue of automatic-to-manual mode transition in the column electric power steering(C-EPS)system.First,we utilized an extended state observer to estimate the driver's steering torque and designed a steering mode transition unit.Second,we validated the mode switching function through an experimental platform.The results indicated that when using the extended state observer for torque estimation,the steering wheel angle and lower input angle errors were approximately±0.5%.The input and observed torque curves were closely aligned,demonstrating excellent tracking capability of the system.In addition,by adopting a steering mode conversion unit,the switch from autonomous control to manual control has been obtained,achieving a smooth and minimal change in steering wheel angle without significant bumps.The experimental results demonstrate that the designed mode switching strategy has the advantages of speed and smoothness,and has strong practical value.
基金This work was supported in part by the Natural Science Foundation of Henan Province,and the specific grant number is 232300420301the initial of author is P.L.,the URL to the sponsors’websites is https://kjt.henan.gov.cn/(accessed on 09 February 2025)And this work was also supported in part by the Fundamental Research Funds for the Universities of Henan Province,and the specific grant number is NSFRF220425,the initial of author is P.L.,the URL to sponsors websites is http://app.hnkjt.gov.cn/web/index.do(accessed on 09 February 2025).
文摘The photovoltaic(PV)output process is inherently complex,often disrupted by a multitude of meteoro-logical factors,while conventional detection methods at PV power stations prove inadequate,compromising prediction accuracy.To address this challenge,this paper introduces a power prediction method that leverages modal switching(MS),weight factor adjustment(WFA),and parallel long short-term memory(PALSTM).Initially,historical PV power station data is categorized into distinct modes based on global horizontal irradiance and converted solar angles.Correlation analysis is then employed to evaluate the impact of various meteorological factors on PV power,selecting those with strong correlations for each specific mode.Subsequently,the weights of meteorological parameters are optimized and adjusted,and a PALSTM neural network is constructed,with its parallel modal parameters refined through training.Depending on the prediction time and input data mode characteristics,the appropriate mode channel is selected to forecast PV power station generation.Ultimately,the feasibility of this method is validated through an illustrative analysis of measured data from an Australian PV power station.Comparative test results underscore the method’s advantages,particularly in scenarios where existing detection methods are lacking and meteorological factors frequently fluctuate,demonstrating its superior prediction accuracy and stability.
基金Supported by Doctoral Fund of Ministry of Education of China(20101101110012)the National Natural Science Foundationof China(51175040)
文摘Based on analyzing the structure and working principle on electric vehicles （EVs） with dual motors coupled by planetarY gears, the control strategy of mode switching was proposed. The power interruption problem on EVs with automatic mechanical transmission （AMT） shifting was resolved. Based on the speed-torque characteristics of the planetary gears and the principle of the auxiliary motor＇ s zero speed braking, control features of mode switching were introduced. The mode shifting between the main motor mode and dual motors coupled driving were studied. Matlab/Simulink was adopted as a platform to develop the simulation model of EVs with dual motors drive system and 3 gears AMT. Simulation results demonstrated that the power interruption of dual motors drive system was solved during mode switching. The power requirements of EVs were satisfied, too.
文摘The control strategy is firstly the first braking power according to the fuzzy control algorithm, considering the speed, the battery SOC and the battery maximum charging power limit to obtain the maximum braking speed, thus the secondary distribution of the hydraulic braking torque. Then the brake control strategy can reduce the impact of the EV braking mode conversion process, and meet the braking demand and brake safety, which proves the effectiveness of the control strategy. In order to ensure the braking stability of the vehicle and further improve the energy utilization rate of electric vehicles, the vehicle speed refueling controller, battery charging state and braking force are used as the energy variables, and the braking force distribution coefficient is taken as the output variable. The braking power distribution coefficient is recommended, considering the stability requirements of the engine, battery, and braking system, to distribute mechanical braking and engine regeneration to the front and rear axles of the machine. Simulation of the developed regenerative braking strategy is analyzed and incorporated into the AVL cruise park model. The results show that this strategy improves braking stability and comfort over the classical ECE curve control strategy, increasing FTP75 by 17.22% compared to the classical ECE curve control strategy
基金supported by Fundamental Research Funds for the Central Universities(No.2019JBM057)。
文摘Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typical DC distribution network with multiple voltage levels is considered as a research object.It is proposed that the interface converters between DC buses with different voltage levels be implemented through the series-parallel combination of full-bridge LLC resonant converters.To realize the decentralized self-discipline control of DC voltage under various working conditions,different slack buses are prepared according to the voltage ranges of the DC buses,and the voltage regulation modes of the DC distribution network are divided into main voltage regulation mode,backup voltage regulation mode,and off-grid voltage droop regulation mode.By introducing a voltage coefficient related to DC voltage deviation as a basis for mode switching,the voltage fluctuations caused by slow switching between control modes in the method of traditional voltage margin control is reduced,facilitating fast and smooth switching between different voltage regulation modes.Finally,a simulation model for DC distribution networks is constructed utilizing MATLAB/Simulink.Simulation results verify the effectiveness and feasibility of the proposed voltage regulation modes and switching methods for DC distribution networks.Finally,an experimental platform is also constructed to verify the feasibility of the mode switching method proposed in this paper.
基金supported by the National Natural Science Foundation of China(No.52177077)by the Science and Technology Project of State Grid Jiangsu Electric Power Co.,Ltd.,Grant J20210148.
文摘Industrial parks(IPs)play a crucial role in facilitating economic efficiency and comprehensive energy utilization in the industrial age.At the same time,multi-energy coupling and management of various types of energy in IP have become serious challenges.In this paper,combined heat and power unit(CHP)model considering operation mode switching characteristics is formulated by exploring its internal composition to improve output flexibility of the energy supply side.Then,heat and electricity integrated energy system(HE-IES)optimal dispatch and pricing model are established,taking electricity and heat demand response strategy and steam thermal inertia property into account.Based on the above models,a mixed-integer bilinear programming framework is designed to coordinate the day-ahead operation and pricing strategy of the HE-IES in the IP.The scenario study is carried out on a practical industrial park in Southern China.Numerical results indicate the proposed mechanism can effectively improve IP’s energy utilization and economic efficiency.
基金funded by the National Natural Science Foundation of China(Grant No.51905219,No.52272368)the Postdoctoral Science Foundation of China(Grant No.2023M731444)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(2020QNRC001)the Key Research and Development Program of Zhenjiang City(No.GY2021001)the Project of Faculty of Agricultural Equipment of Jiangsu University(No.NZXB20210103).
文摘The power split hybrid electric vehicle(HEV)adopts a power coupling configuration featuring dual planetary gearsets and multiple clutches,enabling diverse operational modes through clutch engagement and disengagement.The multi-clutch configuration usually involves the collaboration of two clutches during the transient mode switching process,thereby substantially elevating control complexity.This study focuses on power split HEVs that integrate multi-clutch mechanisms and investigates how different clutch collaboration manners impact the characteristics of transient mode switching.The powertrain model for the power-split HEV is established utilizing matrix-based methodologies.Through the formulation of clutch torque curves and clutch collaboration models,this research systematically explores the effects of clutch engagement timing and the duration of clutch slipping state on transient mode switching behaviors.Building upon this analysis,an optimization problem for control parameters pertaining to the two collaborative clutches is formulated.The simulated annealing algorithm is employed to optimize these control parameters.Simulation results demonstrate that the clutch collaboration manners have a great influence on the transient mode switching performance.Compared with the pre-calibrated benchmark and the optimal solution derived by the genetic algorithm,the maximal longitudinal jerk and clutch slipping work during the transient mode switching process is reduced obviously with the optimal control parameters derived by the simulated annealing algorithm.The study provides valuable insights for the dynamic coordinated control of the power-split HEVs featuring complex clutch collaboration mechanisms.
基金The research is funded partially by the Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province(Grant No.CX(22)3101)the National Key R&D Program(Grant No.2022YFD2001204)+1 种基金the International Science and Technology Cooperation Project of Jiangsu Province(Grant No.BZ2022002)the Natural Science Foundation of Jiangsu Province(Grant No.BK20210407).
文摘The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque distribution is established under different working conditions to improve vehicle power and lateral stability.The anticipated demand torque is initially determined based on the structural characteristics and operational principles of the plant protection machine.Subsequently,a hierarchical control framework is devised by incorporating a formulated switching control strategy.Finally,a simulation model for torque distribution control strategy between shafts is developed on the Matlab/Simulink platform,followed by simulation and experimental verification.The results are presented as follows:the inter-shaft torque distribution strategy established in this paper increases the average longitudinal acceleration by 0.13 m/s^(2) and 0.14 m/s^(2) under the control of low and high to low adhesion road surfaces,respectively.Under the control of the single-line shifting condition,the yaw velocity can successfully follow the expected value with a maximum value of 0.61 rad/s.The side deflection angle of the center of mass does not exceed 2.8°,which can follow the ideal trajectory and improve power and safety.
文摘We report the observation of electric field induced random lasing in a dye doped liquid crystal system. This was achieved by using a liquid crystal host with negative dielectric anisotropy doped with laser dye PM 597 in a 75 μm cell with a homeotropic alignment layer. In the absence of an applied field, only amplified spontaneous emission was observed since the liquid crystal orientation was uniform. However, application of a field resulted in a fieldinduced planar-like configuration with local nonuniformity in liquid crystal orientation. This led to random lasing in the energized state(voltage greater than a transition threshold). The onset of lasing occurs by application of either a spatially homogenous or a spatially inhomogeneous electric field across the liquid crystal. The characteristics of the emission spectra as a function of different(i) dye concentration and(ii) applied voltage were investigated using nanosecond pulsed laser excitation at 532 nm. The effects of using an inhomogeneous field were compared to the use of a homogenous field and reported. It is shown that the spatial configuration can be used to alter the emission spectra of the system. The work is used to suggest a new configuration, referred to here as"reverse mode," for liquid crystal-based random lasers. This new configuration may provide additional avenues for their use in commercial devices.
基金supported by the National Natural Science Foundation of China(NSFC)(62125503,62261160388)Natural Science Foundation of Hubei Province of China(2023AFA028)+1 种基金Key R&D Program of Hubei Province of China(2020BAB001,2021BAA024)Innovation Project of Optics Valley Laboratory(OVL2021BG004).
文摘Mode-division multiplexing technology has been proposed as a crucial technique for enhancing communication capacity and alleviating growing communication demands.Optical switching,which is an essential component of optical communication systems,enables information exchange between channels.However,existing optical switching solutions are inadequate for addressing flexible information exchange among the mode channels.In this study,we introduced a flexible mode switching system in a multimode fibre based on an optical neural network chip.This system utilised the flexibility of on-chip optical neural networks along with an all-fibre orbital angular momentum(OAM)mode multiplexer-demultiplexer to achieve mode switching among the three OAM modes within a multimode fibre.The system adopted an improved gradient descent algorithm to achieve training for arbitrary 3×3 exchange matrices and ensured maximum crosstalk of less than-18.7 dB,thus enabling arbitrary inter-mode channel information exchange.The proposed optical-neural-network-based mode-switching system was experimentally validated by successfully transmitting different modulation formats across various modes.This innovative solution holds promise for providing effective optical switching in practical multimode communication networks.
基金supported by the Jiangsu Key R&D Plan under Grants BE2022053-3.
文摘Electric-hydraulic hybrid power steering(E-HHPS)system,a novel device with multiple modes for commercial electric vehicles,is designed to realize both superior steering feel and high energy efficiency.However,inconsistent steering perfor-mance occurs in the mode-switching process due to different dynamic characteristics of electric and hydraulic components,which even threatens driving safety.In this paper,mode-switching strategy and dynamic compensation control method are proposed for the E-HHPS system to eliminate the inconsistency of steering feel,which comprehensively considers ideal assistance characteristics and energy consumption of the system.Then,the influence of disturbances on system stability is analyzed,and H_(∞)robust controller is employed to guarantee system robustness and stability.The experimental results dem-onstrate that the proposed strategy can provide a steering system with natural steering feel without apparent inconsistency and effectively minimize energy consumption.
文摘This paper explores and proposes a design solution of an integrated skip cycle mode （SCM） control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V process. In order to meet the requirement of a wide temperature range and high yields of products, the schematic extracted from the layout is simulated with five process corners at 27℃ and 90℃. Simulation results demonstrate that the proposed integrated circuit is immune to noise and achieves skipping cycle control when switching mode power supply （SMPS） works with low load or without load.
基金Supported by National Natural Science Foundation of China (Grant Nos. 52375003, 52205006)National Key R&D Program of China (Grant No. 2019YFB1309600)。
文摘To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot(ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of the legarm chain. When the robot performs a task, reconfigurable configuration and mode switching can be achieved using this joint. In contrast from traditional quadruped robots, this robot can stack in a designated area to optimize the occupied volume in a nonworking state. Kinematics modeling and dynamics modeling are established to evaluate the mechanical properties for multiple modes. All working modes of the robot are classified, which can be defined as deployable mode, locomotion mode and operation mode. Based on the stability margin and mechanical modeling, switching analysis and evaluation between each mode is carried out. Finally, the prototype experimental results verify the function realization and switching stability of multimode and provide a design method to integrate and perform multimode for quadruped robots with deployable characteristics.
基金supported by the National Natural Science Fundation of China(5147618751506221)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(2015JQ51792015JM5207)
文摘The chattering characteristic of sliding mode control isanalyzed when it is applied in distributed control systems （DCSs）.For a DCS with random time delay and packet dropout, a discreteswitching system model with time varying sampling period isconstructed based on the time delay system method. The reachinglaw based sliding mode controller is applied in the proposedsystem. The exponential stability condition in the form of linearmatrix inequality is figured out based on the multi-Lyaponov functionmethod. Then, the chattering characteristic is analyzed for theswitching system, and a chattering region related with time varyingsampling period and external disturbance is proposed. Finally, numericalexamples are given to illustrate the validity of the analysisresult.
基金Supported by the National High Technology Research and Development Program of China(863Program)(2012AA111104)
文摘A power train dynamics model of a coaxial parallel hybrid electric vehicle （HEV） was built for different clutch operating states. With the state vector constituted by the motor rotation speed and the clutch transmitting torque at two successive time steps, a discrete state space model for estimating the clutch transmitting torque was built, and the Kalman filtering algorithm was used to estimate the clutch transmitting torque. The Matlab/Simulink was employed to simulate the clutch transmitting torque for two mode-switch processes. Estimation errors were analyzed through compa- ring the estimated and simulated values of the clutch torque. Impact of the noise covariance and the sample time on clutch torque estimation errors were explored. The results show that the developed estimation method can be used to estimate the clutch transmitting torque for HEV with good accura- cy. The results are useful for torque direct control of automatic diaphragm clutches.
基金supported by the Science Technology Project of State Grid Corporation of China(Grant No.52272219000 V)the Major Science and Technology Project of Gansu Province(Grant No.20ZD7GF011).
文摘At present,solar thermal power generation is in the demonstration stage,and the large-scale production is affected by many factors.In view of the characteristics of different operating modes of photothermal power generation,it is analyzed that the turbine needs to be started and stopped frequently due to different operating modes,which will lead to the instability of the output energy and the reduction of power generation efficiency.In this paper,the dynamic equation of energy conversion process is established by using the law of conservation of energy and conservation of mass.Combined with the logic switching criterion of the system,the system model was established by using the extended differential Petri net,and the validity and accuracy of the model were verified.Through the Petri net model of the system,the system’s working mode switching and power generation situation are analyzed due to the difference of direct normal irradiation intensity(DNI).Finally,the accuracy of the model is proved by comparing it with experimental data of the photovoltaic and thermal demonstration projects that have been connected to the grid.
基金financially supported by the National Natural Science Foundation of China(Grant No.52301338)the Sichuan Science and Technology Program(Grant No.2024NSFSC0968).
文摘An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liquid ratios(Q_(g)/Q_(l))and mixture velocities(vm)are non-intrusively and simultaneously captured by high-speed cameras.Both the in-plane and out-of-plane responses of the catenary riser are excited in all considered cases.The slug flow characteristics,including translational velocities,slug lengths,recurrence frequencies,and pressure variations,are analyzed and dis-cussed,as are the dynamic responses of the riser in terms of the amplitudes,space-varying frequency,and modal weight.The dominant modal response based on the root-mean-square amplitude profiles does not match that based on the dominant frequency.Three mode switching types are identified based on the RMS amplitude profiles and the dominant frequency.When vm is small,no mode switching(NMS)is observed in either the in-plane or out-of-plane responses.For mode switching I(MS I),the switching between the first and second modes in the in-plane response is induced by slug flow with different recurrence frequencies in cases of large Q_(g)/Q_(l).However,there is no mode switching in the out-of-plane response.The switching between the first and third modes for the in-plane response and the second and fourth modes for the out-of-plane response(MS II)occurs in cases of relatively high vm and low Q_(g)/Q_(l).
文摘In order to realize the modular design of the microgrid,this paper proposed a new modular topology for the AC-DC mixed microgrid.In that topology,the AC microgrid unit and the DC microgrid unit were packaged together by the back-to-back converter.The battery-supercapacitor hybrid energy storage system was connected to the DC bus of back-to-back converter.By the reasonable design on the battery-supercapacitor hybrid system,the energy storage system could supply the rapid power and energy support for the microgrid spontaneously.The mathematical model and the control algorithm of that microgrid topology were studied.By the simulation analysis,it can be concluded that AC-DC mixed modular microgrid topology could operate steadily on both the grid-connected mode and the isolated mode.Furthermore,we can conclude by the simulation that the designed modular microgrid could operate uninterrupted when the microgrid topology switched from the grid-connected mode to the isolated mode.The seamless switching became the natural property for the modular microgrid.As a result,the modular microgrid topology can be considered as a usual power/load module to realize the friendly power interaction with the power grid.
基金National Natural Science Foundation of China(62205213,12304478,62405194)Natural Science Foundation of Hunan Province(2025JJ60405)+3 种基金Natural Science Foundation of Guangdong Province(2023ZDZX3022,2024A1515012152)Fund of University of South China(231RGC011)Science and Technology Planning Project of Shenzhen Municipality(JCYJ20220818100019040,JCYJ20230808105713028)Guangdong Province Key Construction Discipline Scientific Research Capacity Improvement Project(2021ZDJS107)。
文摘Plasmonic metasurfaces,featuring broadband nonlinear optical responses and exceptional light-field manipulation capabilities,facilitate the passive Q-switching and mode-locking operation of a laser resonator as a saturable absorber(SA)and thus enable the generation of short-and ultrashort pulses.Here,for the first time,to our knowledge,we successfully fabricate a transmission-type mid-infrared plasmonic metasurface SA composed of gold nanostructures on the fluoride substrate,leveraging localized resonance enhancement.Its nonlinear optical(NLO)properties are characterized by a home-made~2.78μm pulsed Z-scan system,demonstrating a remarkable modulation depth of up to 30%.By integrating the plasmonic metasurface SA into a simple linear-cavity Er:ZBLAN fiber laser,stable Q-switched mode-locking(QML)operation is achieved with a maximum average output power of 224 mW at 2.78μm.The output exhibits a Q-switched envelope of 768 ns containing mode-locking pulses with 51.42 ps duration at the fundamental repetition rate of 24.5 MHz.This work further expands the application of plasmonic metasurface SAs to the mid-IR wavelength region,by utilizing their enhanced NLO responses and tailored spectral characteristics,enabling them as a core component for next-generation mid-IR ultrafast lasers.
