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First-Principles Study on Switching Performance and Spin Filtering Efficiency of Dimethyldihydropyrene/Cyclophanediene Single-Molecule Devices with Zigzag Graphene Nanoribbon Electrodes
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作者 Chang-Feng Zheng Yan-Qi Mu +1 位作者 Zong-Liang Li Guang-Ping Zhang 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第5期644-652,I0066-I0072,I0100,共17页
Moleculardeviceswith highswitchingperformance and/or the perfect spin filtering effect have always been the pursuit with the development of molecular electronics.Hereb,yusingthe 2001.0V nonequilibrium.Green's func... Moleculardeviceswith highswitchingperformance and/or the perfect spin filtering effect have always been the pursuit with the development of molecular electronics.Hereb,yusingthe 2001.0V nonequilibrium.Green's function method in combination with the density functionaltheory,the switching performance and spin filtering properties of dimethyldihydropyrene(DHP)/cyclophanediene(CPD)photoswitchable molecule connected by carbon atomic chains(CACs)to two zigzag graphene nanoribbon electrodes have been theoretically investigated.The results show that DHP is more conductive than CPD and therefore an evident switching effect is demonstrated,and the switching ratio(RON/OFF)can reach 4.5×103.It is further revealed that the RoON/OF of DHP/CPD closely depends on the length of CACs.More specifically,the RoN/OFF values of DHP/CPD with odd-numbered CACs are larger than those with even-numbered CACs.More interestingly,a high or even perfect spin filtering effect can be obtained in these investigated DHP/CPD single-molecule devices.Our study is helpful for future design of single-molecule switches and spin filters and provides a way to optimize their performance by means of varying the length of bridging CACs. 展开更多
关键词 Single-molecule switch Spin filtering effect Odd-even effect Nonequilibrium Green's function method Density functional theory
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A Tri-Salt Composite Electrolyte with Temperature Switch Function for Intelligently Temperature-Controlled Lithium Batteries
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作者 Ende Fu Huimin Wang +4 位作者 Yating Zhang Zhenxue Xiao Xiu Zheng Shuai Hao Xueping Gao 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期84-93,共10页
The intense research of lithium-ion batteries has been motivated by their successful applications in mobile devices and electronic vehicles.The emerging of intelligent control in kinds of devices brings new requiremen... The intense research of lithium-ion batteries has been motivated by their successful applications in mobile devices and electronic vehicles.The emerging of intelligent control in kinds of devices brings new requirements for battery systems.The high-energy lithium batteries are expected to respond or react under different environmental conditions.In this work,a tri-salt composite electrolyte is designed with a temperature switch function for intelligently temperature-controlled lithium batteries.Specifically,the halide Li_(3)YBr_(6)together with LiTFSI and LiNO_(3)works as active fillers in a low-melting-point polymer matrix(polyethyleneglycol dimethyl ether(PEGDME)and polyethylene oxide(PEO)),which is further filled into the pre-lithiated alumina fiber skeleton.Above 60°C,the composite electrolyte exists in the liquid state and fully contacts with the working electrodes on the liquid–solid interface,effectively minimizing the interfacial resistance and leading to high discharge capacity in the cell.The electrolyte is changed into a solid state below 30°C so that the ionic conductivity is significantly reduced and the interface resistance is increased dramatically on the solid–solid interface.Therefore,by simply adjusting the temperature,the cell can be turned“ON”or“OFF”intentionally.This novel function of the composite electrolyte has enlightening significance in developing intelligently temperature-controlled lithium batteries. 展开更多
关键词 composite electrolyte halide electrolyte low melting point solid-state battery temperature switch function
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Single-atom catalysts based on polarization switching of ferroelectric In_(2)Se_(3) for N_(2) reduction
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作者 Nan Mu Tingting Bo +3 位作者 Yugao Hu Ruixin Xu Yanyu Liu Wei Zhou 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第8期244-257,共14页
The polarization switching plays a crucial role in controlling the final products in the catalytic pro-cess.The effect of polarization orientation on nitrogen reduction was investigated by anchoring transition metal a... The polarization switching plays a crucial role in controlling the final products in the catalytic pro-cess.The effect of polarization orientation on nitrogen reduction was investigated by anchoring transition metal atoms to form active centers on ferroelectric material In_(2)Se_(3).During the polariza-tion switching process,the difference in surface electrostatic potential leads to a redistribution of electronic states.This affects the interaction strength between the adsorbed small molecules and the catalyst substrate,thereby altering the reaction barrier.In addition,the surface states must be considered to prevent the adsorption of other small molecules(such as *O,*OH,and *H).Further-more,the V@↓-In_(2)Se_(3) possesses excellent catalytic properties,high electrochemical and thermody-namic stability,which facilitates the catalytic process.Machine learning also helps us further ex-plore the underlying mechanisms.The systematic investigation provides novel insights into the design and application of two-dimensional switchable ferroelectric catalysts for various chemical processes. 展开更多
关键词 In_(2)Se_(3) monolayer Density functional theory Ferroelectric switching Single atom catalysts Nitrogen reduction reaction Machine learning
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Modeling, Steady-State Analysis of a SEPIC dc-dc Converter Based on Switching Function and Harmonic Balance Technique 被引量:1
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作者 Ajayi Samuel Taiwo Joseph Yakubu Oricha 《Journal of Power and Energy Engineering》 2014年第4期704-711,共8页
The paper presents modeling approach of a Single Ended Primary Inductance Converter (SEPIC) system. The complete model derivation of the SEPIC converter system has been presented in different modes of operation. Stead... The paper presents modeling approach of a Single Ended Primary Inductance Converter (SEPIC) system. The complete model derivation of the SEPIC converter system has been presented in different modes of operation. Steady state and small signal analysis was carried out on the converter dynamic equations using the method of Harmonic balance Technique. The steady state variables and their respective ripple quantities obtained were plotted against duty ratio D. The results obtained for a supply input voltage of 60 volts to the converter at a duty ratio of D = 0.8 , compares well with simulation results. 展开更多
关键词 SEPIC CONVERTER switching function HARMONIC BALANCE TECHNIQUE
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Stabilization of Functional System with Markovian Switching
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作者 Lizhu Feng Qiong Cai 《Applied Mathematics》 2013年第11期37-43,共7页
There are many papers related to stability, some on suppression or on stabilization are one type of them. Functional differential systems are common and important in practice. They are special situations of neutral di... There are many papers related to stability, some on suppression or on stabilization are one type of them. Functional differential systems are common and important in practice. They are special situations of neutral differential systems and generalization of ordinary differential systems. We discussed conditions on suppression on functional system with Markovian switching in our previous work: “Suppression of Functional System with Markovian Switching”. Based on it, by slightly modifying and adding some conditions, we get this paper. In this paper, we will study a functional system whose coefficient satisfies the local Lipschitz condition and the one-sided polynomial growth condition under Markovian switching. By introducing two appropriate intensity Brownian noise, we find the potential explosion system stabilized. 展开更多
关键词 Stochastic functionAL SYSTEM BROWNIAN Noise Markovian switching BOUNDEDNESS STABILIZATION
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Nonsmooth Control-Lyapunov Function and Stabilization of Nonlinear Switching Systems
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作者 CHEN Jin-huan GAO Yong-liang 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第4期586-591,共6页
In this paper we consider general nonlinear switching systems. Under an additional assumption, we prove that there exists a state space depending switching rule which stabilizes the system in a very general sense.
关键词 STABILIZATION switched systems nonlinear systems krasowski solutions control Lyapunov function
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Estimation of Money Demand Function of South Korea Considering Regime Switching
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作者 Byung Woo Kim 《Chinese Business Review》 2014年第12期740-756,共17页
The stability of money demand function is an important issue in macroeconomic policy implementation. Money demand of Korean economy was estimated. Cointegration test with time dummy variables results show that there i... The stability of money demand function is an important issue in macroeconomic policy implementation. Money demand of Korean economy was estimated. Cointegration test with time dummy variables results show that there is not only long-run equilibrium relationship between money demand and macroeconomic variables, but also structural breaks in this equilibrium relationships. Least squares, state-space, and Marcov switching methods show that there also has been instability (or regime shifts) of parameters in money demand, especially over 1997 crisis and the early 2000s. This fact implies that monetary policy for stabilization might encounter big problems due to change (instability) of money demand. 展开更多
关键词 money demand function COINTEGRATION Marcov switching
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On Impulse Switching Functions of Inverters as an Orthogonal System
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作者 B. Dobrucky M. Pokomy M. Benova 《Journal of Mathematics and System Science》 2014年第12期743-749,共7页
The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using po... The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using power converters they can be strongly non-harmonic, sometimes piecewise constants with zero spaces between them. Then, one deals with power series of time pulses. The impulse switching functions which are orthogonal ones can be derived from these series. The new impulse switching functions are created using Z-transform, inverse Z-transform and numerical series/sequences. The impulse switching functions created this way can be used for both steady- and transient state investigation of converters. 展开更多
关键词 Power converter impulse switching function Z-TRANSFORM inverse Z-transform modelling and simulation steady stateoperation
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Robust admissibility analysis of uncertain switched singular systems:a switched Lyapunov function approach
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作者 林金星 费树岷 +1 位作者 沈炯 于建江 《Journal of Southeast University(English Edition)》 EI CAS 2009年第2期208-212,共5页
The robust admissibility analysis of a class of uncertain discrete-time switched linear singular(SLS) systems for arbitrary switching laws is addressed. The parameter uncertainty is assumed to be norm-bounded. First... The robust admissibility analysis of a class of uncertain discrete-time switched linear singular(SLS) systems for arbitrary switching laws is addressed. The parameter uncertainty is assumed to be norm-bounded. First, by using the switched Lyapunov function approach, some new sufficient conditions ensuring the nominal discrete-time SLS system to be regular, casual and asymptotically stable for arbitrary switching laws are derived in terms of linear matrix inequalities. Then, the robust admissibility condition for the uncertain discrete-time SLS systems is presented. The obtained results can be viewed as an extension of previous works on the switched Lyapunov function approach from the regular switched linear systems to the switched linear singular cases. Numerical examples show the reduced conservatism and effectiveness of the proposed conditions. 展开更多
关键词 switched singular systems robust admissibility switched Lyapunov function parameter uncertainty
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Exponential stabilization of networked control systems and design of switching controller 被引量:5
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作者 Dan MA Jun ZHAO 《控制理论与应用(英文版)》 EI 2006年第1期96-101,共6页
This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is consid... This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is considered in order to reduce the error between theory and application, a sufficient condition for exponential stabilization of networked control systems under a given switching rule is presented by multiple Lyapunov-like functions. These results are presented for both continuous-time and discrete-time domains. Controllers are designed by means of linear matrix inequalities. Sim- ulation results show the feasibility and efficiency of the proposed method. 展开更多
关键词 Networked control systems DROPOUT switching controller Reset map matrix Multiple Lyapunov-like functions Exponential stabilization
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Nonfragile control for a class of uncertain switching fuzzy time-delay systems 被引量:2
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作者 Yi LIU, Jun ZHAO (Key Laboratory of Integrated Automation of Process Industry, Ministry of Education, Northeastern University, Shenyang Liaoning 110004, China) 《控制理论与应用(英文版)》 EI 2010年第2期229-232,共4页
A sufficient condition for the existence of nonfragile state-feedback controllers and a switching law for a class of uncertain switching fuzzy time-delay systems are proposed based on the multiple Lyapunov functions t... A sufficient condition for the existence of nonfragile state-feedback controllers and a switching law for a class of uncertain switching fuzzy time-delay systems are proposed based on the multiple Lyapunov functions technique, under the assumption that the controller gain to be designed has variations. The corresponding results are all formulated in terms of linear matrix inequalities (LMIs). Simulation results show the effectiveness of the design method. 展开更多
关键词 switching system Fuzzy control Nonfragile control Multiple Lyapunov functions
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Global Practical Stabilization of Discrete-Time Switched Affine Systems via a General Quadratic Lyapunov Function and a Decentralized Ellipsoid 被引量:1
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作者 Mohammad Hejri 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2021年第11期1837-1851,共15页
This paper addresses the problem of global practical stabilization of discrete-time switched affine systems via statedependent switching rules.Several attempts have been made to solve this problem via different types ... This paper addresses the problem of global practical stabilization of discrete-time switched affine systems via statedependent switching rules.Several attempts have been made to solve this problem via different types of a common quadratic Lyapunov function and an ellipsoid.These classical results require either the quadratic Lyapunov function or the employed ellipsoid to be of the centralized type.In some cases,the ellipsoids are defined dependently as the level sets of a decentralized Lyapunov function.In this paper,we extend the existing results by the simultaneous use of a general decentralized Lyapunov function and a decentralized ellipsoid parameterized independently.The proposed conditions provide less conservative results than existing works in the sense of the ultimate invariant set of attraction size.Two different approaches are proposed to extract the ultimate invariant set of attraction with a minimum size,i.e.,a purely numerical method and a numerical-analytical one.In the former,both invariant and attractiveness conditions are imposed to extract the final set of matrix inequalities.The latter is established on a principle that the attractiveness of a set implies its invariance.Thus,the stability conditions are derived based on only the attractiveness property as a set of matrix inequalities with a smaller dimension.Illustrative examples are presented to prove the satisfactory operation of the proposed stabilization methods. 展开更多
关键词 Decentralized quadratic Lyapunov function decentralized ellipsoid discrete-time switched affine systems practical stabilization switching power converters
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Hybrid Predictive Control Based on High-Order Differential State Observers and Lyapunov Functions for Switched Nonlinear Systems 被引量:1
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作者 Baili Su Guoyuan Qi Barend J. van Wyk 《Applied Mathematics》 2013年第9期32-42,共11页
In this paper, a hybrid predictive controller is proposed for a class of uncertain switched nonlinear systems based on high-order differential state observers and Lyapunov functions. The main idea is to design an outp... In this paper, a hybrid predictive controller is proposed for a class of uncertain switched nonlinear systems based on high-order differential state observers and Lyapunov functions. The main idea is to design an output feedback bounded controller and a predictive controller for each subsystem using high-order differential state observers and Lyapunov functions, to derive a suitable switched law to stabilize the closed-loop subsystem, and to provide an explicitly characterized set of initial conditions. For the whole switched system, based on the high-order differentiator, a suitable switched law is designed to ensure the whole closed-loop’s stability. The simulation results for a chemical process show the validity of the controller proposed in this paper. 展开更多
关键词 switchED System LYAPUNOV function High Order DIFFERENTIATOR CONTROL Constraint Output Feedback Model Predictive CONTROL Stable Region
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Comparative Investigation of Torque-ripple Suppression Control Strategies Based on Torque-sharing Function for Switched Reluctance Motor 被引量:1
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作者 Tong Chen Guoyang Cheng 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第2期170-178,共9页
Torque ripple is an inherent property of switched reluctance motor(SRM),which seriously affects the control performance and application of the motor.This paper proposes two torque ripple suppression control strategies... Torque ripple is an inherent property of switched reluctance motor(SRM),which seriously affects the control performance and application of the motor.This paper proposes two torque ripple suppression control strategies based on torque-sharing function(TSF).According to the symmetry characteristics of the flux linkage and rotor position curve family,a fourth-order Fourier series is used to fit the SRM flux linkage analytical model.The coefficient of each harmonic term of the flux linkage model is a function related to current,expressed by a sixth-order polynomial.The torque analytical formula can be derived from the flux linkage model.The torque error is calculated via the identified torque model and is compensated through TSF controller in order to reduce torque ripple.The torque model can also be used to establish the torque loop to achieve accurate tracking of the TSF reference torque to reduce torque ripple.Digital simulation was conducted,followed by the implementation on a SRM test bench using a 28335DSP as the master control chip.The experimental results are consistent with the simulation results,and indicate the effectiveness of the proposed schemes. 展开更多
关键词 switched reluctance motor analytical model torque ripple suppression torque-sharing function(TSF)
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Globally Exponential Stability of Memristive Neural Networks With Time-varying Delays and Synchronous Switching 被引量:3
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作者 Yinlu Jiang Chuandong Li 《自动化学报》 CSCD 北大核心 2017年第8期1465-1469,共5页
关键词 全局指数稳定性 神经网络 同步切换 变时滞 记忆 李雅普诺夫 状态轨迹 函数理论
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Model Reference Adaptive Control for Switched Systems with Closed-loop Reference Model Under Arbitrary Switching
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作者 Hao Yang Jing Xie Jun Zhao 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2019年第3期35-42,共8页
This paper explores the model reference adaptive control problem for a class of switched linear systems under arbitrary switching with no need for the measurability of the system state.Based on the state of reference ... This paper explores the model reference adaptive control problem for a class of switched linear systems under arbitrary switching with no need for the measurability of the system state.Based on the state of reference model and the measurable output error, adaptive laws and controllers are designed for switched systems.Each subsystem may have its individual reference model and controller, which increases the design flexibility.The introduction of the closed-loop reference model is to get a better transient performance of the whole switched systems.A numerical example is provided to verify the effectiveness of the main results. 展开更多
关键词 switchED systems MODEL REFERENCE adaptive control common LYAPUNOV function arbitrary switching the CLOSED-LOOP REFERENCE MODEL
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Optimal Switching Control for Nonlinear Systems in A Finite Duration
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作者 MU Xiao-wu LIU Hai-jun 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第2期185-195,共11页
This paper proposes a optimal control problem for a general nonlinear systems with finitely many admissible control settings and with costs assigned to switching of controls. With dynamic programming and viscosity sol... This paper proposes a optimal control problem for a general nonlinear systems with finitely many admissible control settings and with costs assigned to switching of controls. With dynamic programming and viscosity solution theory we show that the switching lower-value function is a viscosity solution of the appropriate systems of quasi-variational inequalities(the appropriate generalization of the Hamilton-Jacobi equation in this context) and that the minimal such switching-storage function is equal to the continuous switching lower-value for the game. With the lower value function a optimal switching control is designed for minimizing the cost of running the systems. 展开更多
关键词 switching systems optimal control viscosity solution value function cost function
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Stability of General Linear Dynamic Multi-Agent Systems under Switching Topologies with Positive Real Eigenvlues
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作者 Shengbo Eben Li Zhitao Wang +2 位作者 Yang Zheng Diange Yang Keyou You 《Engineering》 SCIE EI 2020年第6期688-694,共7页
The time-varying network topology can significantly affect the stability of multi-agent systems.This paper examines the stability of leader-follower multi-agent systems with general linear dynamics and switching netwo... The time-varying network topology can significantly affect the stability of multi-agent systems.This paper examines the stability of leader-follower multi-agent systems with general linear dynamics and switching network topologies,which have applications in the platooning of connected vehicles.The switching interaction topology is modeled as a class of directed graphs in order to describe the information exchange between multi-agent systems,where the eigenvalues of every associated matrix are required to be positive real.The Hurwitz criterion and the Riccati inequality are used to design a distributed control law and estimate the convergence speed of the closed-loop system.A sufficient condition is provided for the stability of multi-agent systems under switching topologies.A common Lyapunov function is formulated to prove closed-loop stability for the directed network with switching topologies.The result is applied to a typical cyber-physical system—that is,a connected vehicle platoon—which illustrates the effectiveness of the proposed method. 展开更多
关键词 STABILITY Multi-agent system switching topologies Common Lyapunov function
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Torque Sharing Function Control of Switched Reluctance Machines with Reduced Current Sensors 被引量:1
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作者 Wei Peng Johan Gyselinck +1 位作者 Jin-Woo Ahn Dong-Hee Lee 《CES Transactions on Electrical Machines and Systems》 2018年第4期355-362,共8页
This paper presents a Torque Sharing Function(TSF)control of Switched Reluctance Machines(SRMs)with different current sensor placements to reconstruct the phase currents.TSF requires precise phase current information ... This paper presents a Torque Sharing Function(TSF)control of Switched Reluctance Machines(SRMs)with different current sensor placements to reconstruct the phase currents.TSF requires precise phase current information to ensure accurate torque control.Two proposed methods with different chopping transistors or a new PWM implementation require four or two current sensors to replace the current sensors on each phase regardless of the phase number.For both approaches,the actual phase current can be easily extracted during the single phase conducting region.However,how to separate the incoming and outgoing phase current values during the commutation region is the difficult issue to deal with.In order to derive these two adjacent currents,the explanations and comparisons of two proposed methods are described.Their effectiveness is verified by experimental results on a four-phase 8/6 SRM.Finally,the approach with a new PWM implementation is selected,which requires only two current sensors for reducing the number of sensors.The control system can be more compact and cheaper. 展开更多
关键词 Current sensor placement pulse width modulation(PWM) switched reluctance machines torque sharing function
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Stability Analysis for Switching of Discrete Linear Singular Systems
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作者 GUO Xiao-li LI Wei MU Xiao-wu 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第2期283-287,共5页
In this paper, we study the stability of discrete linear singular systems by switching controller. Using some recent results on multiple-Lyapunov function technique, we obtain two sufficient conditions of linear singu... In this paper, we study the stability of discrete linear singular systems by switching controller. Using some recent results on multiple-Lyapunov function technique, we obtain two sufficient conditions of linear singular systems. 展开更多
关键词 linear singular systems switching controller multiple-Lyapunov function
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