Efficient torque allocation in over-actuated vehicles poses a central challenge in the domain of advanced vehicle control.These vehicles,featuring redundant actuators,provide an exceptional avenue for enhancing perfor...Efficient torque allocation in over-actuated vehicles poses a central challenge in the domain of advanced vehicle control.These vehicles,featuring redundant actuators,provide an exceptional avenue for enhancing performance,stability,and efficiency.This paper presents a pioneering tendency for torque allocation in the context of over-actuated vehicles,particularly inwheel motor(IWM)driven electric vehicles.We introduce a systematic methodology grounded in analytical modeling,allowing for the efficient reconciliation of multiple,often conflicting objectives.The explicit functions are analytically modeled to enhance stability and energy economy.Additionally,a fuzzy logic-based torque allocation strategy is developed and compared,along with other literature methods,with the analytical models.Simulations are conducted in a joint simulation between Simulink/MATLAB and SCANeR Studio vehicle dynamics simulator,followed by validation on a real-world dataset.Our findings elucidate the proficiency of the analytical models on vehicle performance,stability,computational efficiency,and energy consumption.展开更多
We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate...We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate that the efficiency of the spin-orbit torque increases nearly linearly with the repetition number n,which is in excellent agreement with the spin Hall effect of the Pt_(0.75)Ti_(0.25)being essentially the only source of the observed spin-orbit torque.The perpendicular magnetic anisotropy field is also substantially enhanced by more than a factor of 2 as n increases from 1 to6.The[Pt_(0.75)Ti_(0.25)/Co-Ni multilayers/Ta]_n superlattice additionally exhibits deterministic,low-current-density magnetization switching despite the very large total layer thicknesses.The unique combination of strong spin-orbit torque,robust perpendicular magnetic anisotropy,low-current-density switching,and excellent high thermal stability makes the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice a highly compelling material candidate for ultrafast,energy-efficient,and long-data-retention spintronic technologies.展开更多
Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to smal...Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to small particles within the dipole regime or specific light fields,thereby lacking universality and sometimes leading to ambiguity.To overcome these limitations,we establish a fully analytical and comprehensive framework for optical force/torque based on the Cartesian multipole expansion theory,which is applicable to arbitrary-sized bi-isotropic(chiral)spherical particles immersed in arbitrary monochromatic optical fields.Rigorous expressions are thus derived,which explicitly bridge the optical force/torque with particle-propertydependent coefficients and“force/torque source”quantities characterizing the incident light structures.Such quantities identify the ultimate physical origins of optical force/torque and are systematically classified into four categories based on their parity(P)and duality(D)symmetries.Each category interacts selectively with particles exhibiting specific P and D(a)symmetries,thus inducing distinct optical forces or torques with characteristic physical behaviors.This classification establishes the mutual symmetry-breaking criteria necessary for both particles and light beams to generate optical force/torque,offering a physics-based roadmap for engineering optical manipulations such as chirality sorting,light-driven micromotors,and beyond.展开更多
Passive torque servo system (PTSS) simulates aerodynamic load and exerts the load on actuation system, but PTSS endures position coupling disturbance from active motion of actuation system, and this inherent disturban...Passive torque servo system (PTSS) simulates aerodynamic load and exerts the load on actuation system, but PTSS endures position coupling disturbance from active motion of actuation system, and this inherent disturbance is called extra torque. The most important issue for PTSS controller design is how to eliminate the influence of extra torque. Using backstepping technique, adaptive fuzzy torque control (AFTC) algorithm is proposed for PTSS in this paper, which reflects the essential characteristics of PTSS and guarantees transient tracking performance as well as final tracking accuracy. Takagi-Sugeno (T-S) fuzzy logic system is utilized to compensate parametric uncertainties and unstructured uncertainties. The output velocity of actuator identified model is introduced into AFTC aiming to eliminate extra torque. The closed-loop stability is studied using small gain theorem and the control system is proved to be semiglobally uniformly ultimately bounded. The proposed AFTC algorithm is applied to an electric load simulator (ELS), and the comparative experimental results indicate that AFTC controller is effective for PTSS.展开更多
The direct torque control theory has achieved great success in the control ofinduction motors. However, in the DTC drive system of Permanent Magnet Synchronous Machine (PMSM)proposed a few years ago, there are many ba...The direct torque control theory has achieved great success in the control ofinduction motors. However, in the DTC drive system of Permanent Magnet Synchronous Machine (PMSM)proposed a few years ago, there are many basic theoretical problems that must be clarified. Thispaper describes an investigation about the effect of the zero voltage space vectors in the DTCsystem of PMSM and points out that if using the zero voltage space vectors rationally, not only canthe DTC system be driven successfully but also the torque ripple is reduced and the performance ofthe system is improved. This paper also studies the sensorless technique in the DTC system of PMSMand configures the DTC system of PMSM with sensorless technique including zero voltage spacevectors. Numerical simulations and experimental tests have proved the theory correct. In thecondition of sensor-less, the DTC system of PMSM is wide-rangely speed adjusting, and the ratio ofspeed adjustment is 1: 100.展开更多
Existing research on the traction control system（TCS） mainly focuses on control methods, such as the PID control, fuzzy logic control, etc, aiming at achieving an ideal slip rate of the drive wheel over long control...Existing research on the traction control system（TCS） mainly focuses on control methods, such as the PID control, fuzzy logic control, etc, aiming at achieving an ideal slip rate of the drive wheel over long control periods. The initial output of the TCS （referred to as the torque base in this paper）, which has a great impact on the driving performance of the vehicle in early cycles, remains to be investigated. In order to improve the control performance of the TCS in the first several cycles, an algorithm is proposed to determine the torque base. First, torque bases are calculated by two different methods, one based on states judgment and the other based on the vehicle dynamics. The confidence level of the torque base calculated based on the vehicle dynamics is also obtained. The final torque base is then determined based on the two torque bases and the confidence level. Hardware-in-the-loop（HIL） simulation and vehicle tests emulating sudden start on low friction roads have been conducted to verify the proposed algorithm. The control performance of a PID-controlled TCS with and without the proposed torque base algorithm is compared, showing that the proposed algorithm improves the performance of the TCS over the first several cycles and enhances about 5% vehicle speed by contrast. The proposed research provides a more proper initial value for TCS control, and improves the performance of the first several control cycles of the TCS.展开更多
This paper introduces four PWM modes used in the sensorless brushless DC motor control system, analyzes their different influences on the commutation torque ripple in detail, and selects the best PWM mode in four give...This paper introduces four PWM modes used in the sensorless brushless DC motor control system, analyzes their different influences on the commutation torque ripple in detail, and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC(BLDC) motors. Simulation and experimental results show that the selection is correct and practical.展开更多
A 3D torque converter design system is developed based on numerical investigation into flow field and CAD technology. The 3D steady-state flow field simulation is undertaken by using time averaged Reynolds equation an...A 3D torque converter design system is developed based on numerical investigation into flow field and CAD technology. The 3D steady-state flow field simulation is undertaken by using time averaged Reynolds equation and k-epsilon turbulence model, with mixing-plane boundary conditions at three section interfaces. The blades are designed according to the flow field characteristics by using a reverse design method in the system. The accurateness of numerical analysis and the validity of design system are verified by the fluid field experiment of desingn example of the torque converter. This kind of design and analysis system for torque converter based on integration of comput ationol fluid dynamics （CFD） and CAD is a powerful tool for torque converter manufacturing, but also a prettg important significance for research and development.展开更多
A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two pha...A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral(PI)-based and sliding mode(SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion(THD)index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.展开更多
Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. Ho...Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. However, the problem of complexity of selecting vectors and capacitor voltage unbalance needs to be solved when the algorithm of direct torque control （DTC） is implemented on DCMLI. In this paper, a fuzzy DTC system of an induction machine fed by a three-level neutral-point-clamped （NPC） inverter is proposed. After introducing fuzzy logic, optimal selecting switching state is realized by applying various strategies which can distinguish the grade of the errors of stator flux linkage, torque, the neutral-point potential, and the position of stator flux linkage. Consequently, the neutral-point potential unbalance, the dr/dr of output voltage and the switching loss are restrained effectively, and desirable dynamic and steady-state performances of induction machines can be obtained for the DTC scheme. A design method of the fuzzy controller is introduced in detail, and the relevant simulation and experimental results have verified the feasibility of the proposed control algorithm.展开更多
In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the r...In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the robot joint with harmonic drive to acquire high precision torque output.Through analyzing the structures of the harmonic drive and experiment apparatus,a scheme of the proposed joint torque estimation method based on both the dynamic characteristics and unscented Kalman filter(UKF)is designed and built.Based on research and scheme,torque estimation methods in view of only harmonic drive compliance model and compliance model with the Kalman filter are simulated as guidance and reference to promote the research on the torque estimation technique.Finally,a promoted torque estimation method depending on both harmonic drive compliance model and UKF is designed,and simulation results compared with the measurements of a commercial torque sensor,have verified the effectiveness of the proposed method.展开更多
Employing matrix converter （MC） as driving mode, the strategy of model predictive torque control （MPTC） is proposed for three phase permanent magnet synchronous motor （PMSM） system. MC is applied instead of conv...Employing matrix converter （MC） as driving mode, the strategy of model predictive torque control （MPTC） is proposed for three phase permanent magnet synchronous motor （PMSM） system. MC is applied instead of conventional AC DC AC converter to increase the power factor （PF） of the system input side. MPTC is used to select optimal voltage space vector to enable the system to have satisfactory torque and flux control effect. The resultant MPTC strategy not only makes the MC fed PMSM system operate reliably and have perfect control performance, but also makes the PF of the system input side be 1. Compared with direct torque control （DTC）, the proposed MPTC strategy guarantees that MC fed PMSM has better command following characteristics in the presence of variation of load torque and tracking reference speed. Simulation results verify the feasibility and effectiveness of the proposed strategy.展开更多
A mobile satellite communication system(MSCS)is a device installed on a moving carrier for mobile satellite communication.It can eliminate disturbance and maintain continuous satellite communication when the carrier i...A mobile satellite communication system(MSCS)is a device installed on a moving carrier for mobile satellite communication.It can eliminate disturbance and maintain continuous satellite communication when the carrier is moving.Because of many advantages of mobile satellite communication,the MSCSs are becoming more and more popular in modern mobile communication.In this paper,a typical ship-mounted MSCS is studied.The dynamic model of the system is derived using the generalized Lagrange method both in the joint space and in the workspace.Based on the dynamic model,a nonlinear computed torque controller with trajectory planning is designed to track an aimed satellite with a satisfied transient response.Simulation results in two different situations are presented to show the tracking performance of the controller.展开更多
The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC sys...The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC system with stator flux hexagon and circle trajectories. The simulation waveforms of flux, torque and current characters with two flux trajectories were given. Experiments were carried out in an AC drive system based on induction motor and two-level inverter. A dual-CPU structure was used and the communication with two CPUs was obtained by a dual-port RAM in this system.展开更多
An adaptive load torque observer is presented to compensate the torque ripple in PMSM servo system. A simple adaptive scheme is derived using Popov ＇ s hyperstability theory. The torque ripple detected by the observe...An adaptive load torque observer is presented to compensate the torque ripple in PMSM servo system. A simple adaptive scheme is derived using Popov ＇ s hyperstability theory. The torque ripple detected by the observer is compensated by a feed forwarding equivalent current which gives fast response. The noisy current information is exempt from the observer to avoid its deterioration to the quality of the observer. The speed measurement delay is considered by using observed speed sinee the instantaneous velocity can＇t be estimated precisely at low speed because of too few position pulses from the absolute encoder during one time interval. Simulation and experimental results demonstrate that the proposed method can improve the dynamic performance of PMSM servo system satisfyingly.展开更多
A novel speed sensor-less direct torque control induction motor drive system for the mining locomotive haulage is presented in the paper. Rotor speed identification is based on the model reference adaptive control the...A novel speed sensor-less direct torque control induction motor drive system for the mining locomotive haulage is presented in the paper. Rotor speed identification is based on the model reference adaptive control theory with neural network using back propagation algorithm. The system is implemented using a real-time TMS320F240 digital signal processor. The simulation study and experiment results indicate that the suggested system has good performance.展开更多
Analyzed working principle and starting process of asynchronous motor direct torque control system. In order to solve the problem of serious fluctuation of starting current in traditional control scheme, the author pu...Analyzed working principle and starting process of asynchronous motor direct torque control system. In order to solve the problem of serious fluctuation of starting current in traditional control scheme, the author puts forward a new kind of starting method which can limit voltage value to achieve the goal of reducing fluctuation of the current by increasing zero voltage vectors during the stage of starting. The author has also carried on simulation study on the system, and the result of simulation study shows that this method is effectual.展开更多
Switched Reluctance Motors(SRMs),outfitted with rugged construction,good speed range,high torque density,and rare earth-free nature that outweigh induction motors(IM)and permanent magnet synchronous motor(PMSM),afford...Switched Reluctance Motors(SRMs),outfitted with rugged construction,good speed range,high torque density,and rare earth-free nature that outweigh induction motors(IM)and permanent magnet synchronous motor(PMSM),afford a broad range of applications in the domain of electric vehicles(EVs).Standard copper magnetic wire and low-carbon steel laminations are used to construct SRMs,which give them high efficiency in the range of 85-95%.Despite SRM's desirable features over traditional motor-speed drives,high torque ripples and radial distortions constrain their deployment in EVs.Precise rotor position is imperative for effective management of the speed and torque of SRMs.This paper provides an illustrative compendium on review of the torque-speed control and ripple mitigation techniques using design enhancements and control methods for SRM drives for EV applications.The various schemes were evaluated on their performance metricsoperational speed range,control complexity,practical realization,need for pre-stored parameters(look-up tables of current,inductance and torque profiles)and motor controller memory requirements.The findings provide valuable insights into balancing the gains and trade-offs associated with EV applications.Furthermore,they pinpoint opportunities for enhancement by analyzing the cost and technical aspects of different SRM controllers.展开更多
In recent decades,optical micro/nano manipulation has made remarkable strides in the fields of biology and the physical sciences,benefiting from both theoretical and experimental advances in optical forces.The emergen...In recent decades,optical micro/nano manipulation has made remarkable strides in the fields of biology and the physical sciences,benefiting from both theoretical and experimental advances in optical forces.The emergence of optical torques has further enhanced the capabilities and possibilities of optical micro/nano manipulation,opening the door to exciting new applications.In this review,we delve into the fundamentals and recent breakthroughs in the realm of optical micro/nano manipulation using optical torques.We introduce the advancements in optical manipulation based on optical torques from engineered light fields and objects,and highlight the latest developments in applying optical torques to cutting-edge physical and biological scenarios,with a special emphasis on the detection and manipulation of biological structures.Finally,we conclude by outlining our vision for the current and future directions of this field,including the integration of optical torque and micro/nano technologies,the utilization of special light fields,and the development of deeplearning-assisted optical torque design.展开更多
Compared to the conventional permanent magnet synchronous machine(PMSM),the main characteristic of permanent magnet torque machine(PMTM)with high torque is that armature current is high,which has a great influence on ...Compared to the conventional permanent magnet synchronous machine(PMSM),the main characteristic of permanent magnet torque machine(PMTM)with high torque is that armature current is high,which has a great influence on magnetic circuit saturation,so this paper proposes a novel analytical method(AM)considering this problem.The key of this new AM is to consider armature reaction flux and armature leakage flux,which are closely related to output torque.Firstly,the expressions,including magnetomotive force(MMF)generated by permanent magnets(PMs)and armature windings are derived,and meanwhile slotting effect is considered by planning flux path.In addition,the expression of leakage flux density generated by armature windings are calculated,and flux density equivalence coefficient of tooth is calculated to be 2/3,which is used to solve the problem of uneven saturation of each tooth.Then,based on main flux factor and leakage flux factor proposed,an improved iteration process is proposed,and by this new process,the flux density of each yoke and tooth can be obtained,which is beneficial to obtain more accurate air-gap flux density and flux linkage.Finally,a prototype of 60-pole 54-slot is fabricated,and the performances of the electric machine,such as back electromotive force(EMF)and output torque,are calculated by this new AM and finite element method(FEM).The results of FEM and experimental test show that this new AM is good enough to calculate the performance of PMTM.展开更多
基金carried out within the framework of the V3EA Project“Electric,Energy Efficient,and Autonomous Vehicle”(2021-2025)supported by the Research National Agency(ANR)of the French Government。
文摘Efficient torque allocation in over-actuated vehicles poses a central challenge in the domain of advanced vehicle control.These vehicles,featuring redundant actuators,provide an exceptional avenue for enhancing performance,stability,and efficiency.This paper presents a pioneering tendency for torque allocation in the context of over-actuated vehicles,particularly inwheel motor(IWM)driven electric vehicles.We introduce a systematic methodology grounded in analytical modeling,allowing for the efficient reconciliation of multiple,often conflicting objectives.The explicit functions are analytically modeled to enhance stability and energy economy.Additionally,a fuzzy logic-based torque allocation strategy is developed and compared,along with other literature methods,with the analytical models.Simulations are conducted in a joint simulation between Simulink/MATLAB and SCANeR Studio vehicle dynamics simulator,followed by validation on a real-world dataset.Our findings elucidate the proficiency of the analytical models on vehicle performance,stability,computational efficiency,and energy consumption.
基金supported by the Beijing Natural Science Foundation(Grant No.Z230006)the National Key Research and Development Program of China(Grant No.2022YFA1204000)the National Natural Science Foundation of China(Grant Nos.12274405 and 12393831)。
文摘We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate that the efficiency of the spin-orbit torque increases nearly linearly with the repetition number n,which is in excellent agreement with the spin Hall effect of the Pt_(0.75)Ti_(0.25)being essentially the only source of the observed spin-orbit torque.The perpendicular magnetic anisotropy field is also substantially enhanced by more than a factor of 2 as n increases from 1 to6.The[Pt_(0.75)Ti_(0.25)/Co-Ni multilayers/Ta]_n superlattice additionally exhibits deterministic,low-current-density magnetization switching despite the very large total layer thicknesses.The unique combination of strong spin-orbit torque,robust perpendicular magnetic anisotropy,low-current-density switching,and excellent high thermal stability makes the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice a highly compelling material candidate for ultrafast,energy-efficient,and long-data-retention spintronic technologies.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204117,12564043,12174076,12074084,and 12074169)the Guangxi Science and Technology Project(Grant Nos.2023GXNSFFA026002,2024GXNSFBA010261,2021GXNSFDA196001,and AD23026117)+3 种基金the Open Project of State Key Laboratory of Surface Physics in Fudan University(Grant No.KF2022_15)the Guangdong Province Talent Recruitment Program(Grant No.2021QN02C103)supported by the Research Grants Council of Hong Kong(Grant Nos.16310422 and AoE/P-502/20)the Innovation Project of Guangxi Graduate Education(Grant No.11241018)。
文摘Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to small particles within the dipole regime or specific light fields,thereby lacking universality and sometimes leading to ambiguity.To overcome these limitations,we establish a fully analytical and comprehensive framework for optical force/torque based on the Cartesian multipole expansion theory,which is applicable to arbitrary-sized bi-isotropic(chiral)spherical particles immersed in arbitrary monochromatic optical fields.Rigorous expressions are thus derived,which explicitly bridge the optical force/torque with particle-propertydependent coefficients and“force/torque source”quantities characterizing the incident light structures.Such quantities identify the ultimate physical origins of optical force/torque and are systematically classified into four categories based on their parity(P)and duality(D)symmetries.Each category interacts selectively with particles exhibiting specific P and D(a)symmetries,thus inducing distinct optical forces or torques with characteristic physical behaviors.This classification establishes the mutual symmetry-breaking criteria necessary for both particles and light beams to generate optical force/torque,offering a physics-based roadmap for engineering optical manipulations such as chirality sorting,light-driven micromotors,and beyond.
基金National High-tech Research and Development Program of China (2009AA04Z412)"111" ProjectBUAA Fund of Graduate Education and Development
文摘Passive torque servo system (PTSS) simulates aerodynamic load and exerts the load on actuation system, but PTSS endures position coupling disturbance from active motion of actuation system, and this inherent disturbance is called extra torque. The most important issue for PTSS controller design is how to eliminate the influence of extra torque. Using backstepping technique, adaptive fuzzy torque control (AFTC) algorithm is proposed for PTSS in this paper, which reflects the essential characteristics of PTSS and guarantees transient tracking performance as well as final tracking accuracy. Takagi-Sugeno (T-S) fuzzy logic system is utilized to compensate parametric uncertainties and unstructured uncertainties. The output velocity of actuator identified model is introduced into AFTC aiming to eliminate extra torque. The closed-loop stability is studied using small gain theorem and the control system is proved to be semiglobally uniformly ultimately bounded. The proposed AFTC algorithm is applied to an electric load simulator (ELS), and the comparative experimental results indicate that AFTC controller is effective for PTSS.
基金Aeronautical Science Emphasis foundation of China( 98Z5 2 0 0 1) Delta Power Electronics Science &Education DevelopmentF und
文摘The direct torque control theory has achieved great success in the control ofinduction motors. However, in the DTC drive system of Permanent Magnet Synchronous Machine (PMSM)proposed a few years ago, there are many basic theoretical problems that must be clarified. Thispaper describes an investigation about the effect of the zero voltage space vectors in the DTCsystem of PMSM and points out that if using the zero voltage space vectors rationally, not only canthe DTC system be driven successfully but also the torque ripple is reduced and the performance ofthe system is improved. This paper also studies the sensorless technique in the DTC system of PMSMand configures the DTC system of PMSM with sensorless technique including zero voltage spacevectors. Numerical simulations and experimental tests have proved the theory correct. In thecondition of sensor-less, the DTC system of PMSM is wide-rangely speed adjusting, and the ratio ofspeed adjustment is 1: 100.
基金supported by National Natural Science Foundation of China(Grant Nos. 50905092, 51275557)Open Foundation of State Key Laboratory of Automotive Safety and Energy(Grant Nos. zz2011-052, zz2011-021)
文摘Existing research on the traction control system（TCS） mainly focuses on control methods, such as the PID control, fuzzy logic control, etc, aiming at achieving an ideal slip rate of the drive wheel over long control periods. The initial output of the TCS （referred to as the torque base in this paper）, which has a great impact on the driving performance of the vehicle in early cycles, remains to be investigated. In order to improve the control performance of the TCS in the first several cycles, an algorithm is proposed to determine the torque base. First, torque bases are calculated by two different methods, one based on states judgment and the other based on the vehicle dynamics. The confidence level of the torque base calculated based on the vehicle dynamics is also obtained. The final torque base is then determined based on the two torque bases and the confidence level. Hardware-in-the-loop（HIL） simulation and vehicle tests emulating sudden start on low friction roads have been conducted to verify the proposed algorithm. The control performance of a PID-controlled TCS with and without the proposed torque base algorithm is compared, showing that the proposed algorithm improves the performance of the TCS over the first several cycles and enhances about 5% vehicle speed by contrast. The proposed research provides a more proper initial value for TCS control, and improves the performance of the first several control cycles of the TCS.
文摘This paper introduces four PWM modes used in the sensorless brushless DC motor control system, analyzes their different influences on the commutation torque ripple in detail, and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC(BLDC) motors. Simulation and experimental results show that the selection is correct and practical.
基金Natioual Hi-tech Research and Development Program-of China(863 Program. No.2007AA04Z132).
文摘A 3D torque converter design system is developed based on numerical investigation into flow field and CAD technology. The 3D steady-state flow field simulation is undertaken by using time averaged Reynolds equation and k-epsilon turbulence model, with mixing-plane boundary conditions at three section interfaces. The blades are designed according to the flow field characteristics by using a reverse design method in the system. The accurateness of numerical analysis and the validity of design system are verified by the fluid field experiment of desingn example of the torque converter. This kind of design and analysis system for torque converter based on integration of comput ationol fluid dynamics （CFD） and CAD is a powerful tool for torque converter manufacturing, but also a prettg important significance for research and development.
基金supported by the National Natural Science Foundation of China(61463025).
文摘A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral(PI)-based and sliding mode(SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion(THD)index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.
文摘Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. However, the problem of complexity of selecting vectors and capacitor voltage unbalance needs to be solved when the algorithm of direct torque control （DTC） is implemented on DCMLI. In this paper, a fuzzy DTC system of an induction machine fed by a three-level neutral-point-clamped （NPC） inverter is proposed. After introducing fuzzy logic, optimal selecting switching state is realized by applying various strategies which can distinguish the grade of the errors of stator flux linkage, torque, the neutral-point potential, and the position of stator flux linkage. Consequently, the neutral-point potential unbalance, the dr/dr of output voltage and the switching loss are restrained effectively, and desirable dynamic and steady-state performances of induction machines can be obtained for the DTC scheme. A design method of the fuzzy controller is introduced in detail, and the relevant simulation and experimental results have verified the feasibility of the proposed control algorithm.
基金supported by the National Natural Science Foundation of China(51879055)。
文摘In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the robot joint with harmonic drive to acquire high precision torque output.Through analyzing the structures of the harmonic drive and experiment apparatus,a scheme of the proposed joint torque estimation method based on both the dynamic characteristics and unscented Kalman filter(UKF)is designed and built.Based on research and scheme,torque estimation methods in view of only harmonic drive compliance model and compliance model with the Kalman filter are simulated as guidance and reference to promote the research on the torque estimation technique.Finally,a promoted torque estimation method depending on both harmonic drive compliance model and UKF is designed,and simulation results compared with the measurements of a commercial torque sensor,have verified the effectiveness of the proposed method.
基金National Natural Science Foundation of China(No.61463025)Program for Excellent Team of Scientific Research in Lanzhou Jiaotong University(No.201701)
文摘Employing matrix converter （MC） as driving mode, the strategy of model predictive torque control （MPTC） is proposed for three phase permanent magnet synchronous motor （PMSM） system. MC is applied instead of conventional AC DC AC converter to increase the power factor （PF） of the system input side. MPTC is used to select optimal voltage space vector to enable the system to have satisfactory torque and flux control effect. The resultant MPTC strategy not only makes the MC fed PMSM system operate reliably and have perfect control performance, but also makes the PF of the system input side be 1. Compared with direct torque control （DTC）, the proposed MPTC strategy guarantees that MC fed PMSM has better command following characteristics in the presence of variation of load torque and tracking reference speed. Simulation results verify the feasibility and effectiveness of the proposed strategy.
基金supported by National Natural Science Foundation of China(Nos.61074023 and 60975075)Natural Science Foundation of Jiangsu Province of China(No.BK2008404)+1 种基金Science and Technology Pillar Program of Jiangsu Province of China(No.BE2009160)Innovation Project of Graduate Students of Jiangsu Province of China(No.CXZZ 0254)
文摘A mobile satellite communication system(MSCS)is a device installed on a moving carrier for mobile satellite communication.It can eliminate disturbance and maintain continuous satellite communication when the carrier is moving.Because of many advantages of mobile satellite communication,the MSCSs are becoming more and more popular in modern mobile communication.In this paper,a typical ship-mounted MSCS is studied.The dynamic model of the system is derived using the generalized Lagrange method both in the joint space and in the workspace.Based on the dynamic model,a nonlinear computed torque controller with trajectory planning is designed to track an aimed satellite with a satisfied transient response.Simulation results in two different situations are presented to show the tracking performance of the controller.
文摘The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC system with stator flux hexagon and circle trajectories. The simulation waveforms of flux, torque and current characters with two flux trajectories were given. Experiments were carried out in an AC drive system based on induction motor and two-level inverter. A dual-CPU structure was used and the communication with two CPUs was obtained by a dual-port RAM in this system.
文摘An adaptive load torque observer is presented to compensate the torque ripple in PMSM servo system. A simple adaptive scheme is derived using Popov ＇ s hyperstability theory. The torque ripple detected by the observer is compensated by a feed forwarding equivalent current which gives fast response. The noisy current information is exempt from the observer to avoid its deterioration to the quality of the observer. The speed measurement delay is considered by using observed speed sinee the instantaneous velocity can＇t be estimated precisely at low speed because of too few position pulses from the absolute encoder during one time interval. Simulation and experimental results demonstrate that the proposed method can improve the dynamic performance of PMSM servo system satisfyingly.
文摘A novel speed sensor-less direct torque control induction motor drive system for the mining locomotive haulage is presented in the paper. Rotor speed identification is based on the model reference adaptive control theory with neural network using back propagation algorithm. The system is implemented using a real-time TMS320F240 digital signal processor. The simulation study and experiment results indicate that the suggested system has good performance.
文摘Analyzed working principle and starting process of asynchronous motor direct torque control system. In order to solve the problem of serious fluctuation of starting current in traditional control scheme, the author puts forward a new kind of starting method which can limit voltage value to achieve the goal of reducing fluctuation of the current by increasing zero voltage vectors during the stage of starting. The author has also carried on simulation study on the system, and the result of simulation study shows that this method is effectual.
基金supported in part by the Universitat Politècnica de València under grant PAID-10-21supported through AMRITA Seed Grant(Proposal ID:ASG2022188)。
文摘Switched Reluctance Motors(SRMs),outfitted with rugged construction,good speed range,high torque density,and rare earth-free nature that outweigh induction motors(IM)and permanent magnet synchronous motor(PMSM),afford a broad range of applications in the domain of electric vehicles(EVs).Standard copper magnetic wire and low-carbon steel laminations are used to construct SRMs,which give them high efficiency in the range of 85-95%.Despite SRM's desirable features over traditional motor-speed drives,high torque ripples and radial distortions constrain their deployment in EVs.Precise rotor position is imperative for effective management of the speed and torque of SRMs.This paper provides an illustrative compendium on review of the torque-speed control and ripple mitigation techniques using design enhancements and control methods for SRM drives for EV applications.The various schemes were evaluated on their performance metricsoperational speed range,control complexity,practical realization,need for pre-stored parameters(look-up tables of current,inductance and torque profiles)and motor controller memory requirements.The findings provide valuable insights into balancing the gains and trade-offs associated with EV applications.Furthermore,they pinpoint opportunities for enhancement by analyzing the cost and technical aspects of different SRM controllers.
基金supported by the National Natural Science Foundation of China(62192770,62305252,62205246,62020106009,62192771,61925504)National Key Research and Development Program of China(2023YFF0615604 and 2023YFF0613600)+6 种基金Science and Technology Commission of Shanghai Municipality(21JC1406100)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)Science and Technology Commission of Shanghai Municipality(No.22ZR1432400)Shanghai Pilot Program for Basic Research,and Fundamental Research Funds for the Central Universities.D.P.T.acknowledges National Natural Science Foundation of China(No.62375232)University Grants Committee/Research Grants Council of the Hong Kong Special Administrative Region,China[Project No.AoE/P-502/20,CRF Project:C5031-22G and C1015-21E,GRF Project:CityU15303521CityU11305223,and Germany/Hong Kong Joint Research Scheme:GCityU101/22]City University of Hong Kong[Project No.9380131,9610628,and 7005867].
文摘In recent decades,optical micro/nano manipulation has made remarkable strides in the fields of biology and the physical sciences,benefiting from both theoretical and experimental advances in optical forces.The emergence of optical torques has further enhanced the capabilities and possibilities of optical micro/nano manipulation,opening the door to exciting new applications.In this review,we delve into the fundamentals and recent breakthroughs in the realm of optical micro/nano manipulation using optical torques.We introduce the advancements in optical manipulation based on optical torques from engineered light fields and objects,and highlight the latest developments in applying optical torques to cutting-edge physical and biological scenarios,with a special emphasis on the detection and manipulation of biological structures.Finally,we conclude by outlining our vision for the current and future directions of this field,including the integration of optical torque and micro/nano technologies,the utilization of special light fields,and the development of deeplearning-assisted optical torque design.
基金supported in part by the National Natural Science Foundation of China under Grant 52125701.
文摘Compared to the conventional permanent magnet synchronous machine(PMSM),the main characteristic of permanent magnet torque machine(PMTM)with high torque is that armature current is high,which has a great influence on magnetic circuit saturation,so this paper proposes a novel analytical method(AM)considering this problem.The key of this new AM is to consider armature reaction flux and armature leakage flux,which are closely related to output torque.Firstly,the expressions,including magnetomotive force(MMF)generated by permanent magnets(PMs)and armature windings are derived,and meanwhile slotting effect is considered by planning flux path.In addition,the expression of leakage flux density generated by armature windings are calculated,and flux density equivalence coefficient of tooth is calculated to be 2/3,which is used to solve the problem of uneven saturation of each tooth.Then,based on main flux factor and leakage flux factor proposed,an improved iteration process is proposed,and by this new process,the flux density of each yoke and tooth can be obtained,which is beneficial to obtain more accurate air-gap flux density and flux linkage.Finally,a prototype of 60-pole 54-slot is fabricated,and the performances of the electric machine,such as back electromotive force(EMF)and output torque,are calculated by this new AM and finite element method(FEM).The results of FEM and experimental test show that this new AM is good enough to calculate the performance of PMTM.
