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Coupling Characteristics and Control of Dual Mechanical Port Machine with Spoke Type Permanent Magnet Arrangement
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作者 ZHUANG Xingming SONG Qiang +2 位作者 WEN Xuhui ZHAO Feng FAN Tao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第6期1186-1202,共17页
Dual mechanical port machine(DMPM), as a novel electromechanical energy conversion device, has attracted widespread attention. DMPM with spoke type permanent magnet arrangements(STPM-DMPM), which is one of several... Dual mechanical port machine(DMPM), as a novel electromechanical energy conversion device, has attracted widespread attention. DMPM with spoke type permanent magnet arrangements(STPM-DMPM), which is one of several types of DMPM, has been of interest recently. The unique coupling characteristics of STPM-DMPM are beneficial to improving system performance, but these same characteristics increase the difficulties of control. Now there has been little research about the control of STPM-DMPM, and this has hindered its practical application. Based on a mathematical model of STPM-DMPM, the coupling characteristics and the merits and demerits of such devices are analyzed as applied to a hybrid system. The control strategies for improving the disadvantages and for utilizing the advantage of coupling are researched. In order to weaken the interaction effect of torque outputs in the inner motor and the outer motor that results from coupling in STPM-DMPM, a decoupling control method based on equivalent current control is proposed, and independent torque control for the inner motor and outer motor is achieved. In order to solve address the problem of adequately utilization of coupling, minimizing the overall copper loss of the inner motor and the outer motor of STPM-DMPM is taken as the optimization objective for optimal control, and the purpose of utilizing the coupling adequately and reasonably is achieved. The verification tests of the proposed decoupling control and optimal control strategies are carried out on a prototype STPM-DMPM, and the experimental results show that the interaction effect of torque outputs in the inner motor and the outer motor can be markedly weakened through use of the control method. The overall copper loss of the inner motor and the outer motor can be markedly reduced through use of the optimal control method, while the power output remains unchanged. A breakthrough in the control problem of STPM-DMPM is accomplished by combining the control methods. Good performance in the control of STPM-DMPM will enhance its practicality, particularly as applied to hybrid systems. 展开更多
关键词 dual mechanical port machine spoke type permanent magnet arrangement coupling characteristics decoupling control optimal control
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Coupling Characteristics of DFIG-based WT Considering Reactive Power Control and Its Impact on Phase/Amplitude Transient Stability in a Rotor Speed Control Timescale
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作者 Wangqianyun Tang Jiabing Hu +2 位作者 Rui Zhang Xu Chen Zhengang Yang 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2022年第2期511-522,共12页
The transient stability issues caused by doubly fed induction generator(DFIG)-based wind turbines(WTs)are receiving increasing attention.The q-axis reactive power control(QCtrl),as an essential part of DFIG-based WTs,... The transient stability issues caused by doubly fed induction generator(DFIG)-based wind turbines(WTs)are receiving increasing attention.The q-axis reactive power control(QCtrl),as an essential part of DFIG-based WTs,has a significant impact on its transient response.In this paper,the impact of QCtrl on the phase/amplitude transient stability of a DFIGbased WT-dominated system is analyzed from the perspective of internal voltage amplitude-phase coupling characteristics.First,an amplitude/phase dynamic model of a DFIG-based WT in rotor speed control timescale(in seconds,corresponding to traditional electromechanical timescale)is developed.Then,in comparison with familiar synchronous generators(SGs),an inherently amplitude-phase characteristic of internal voltage for a DFIG-based WT is identified.Next,taking the DFIG-based WTdominated system as an example,the impact of QCtrl on system transient stability via the internal coupling paths is analyzed.A novel phase-amplitude coupling instability mechanism is found,which is different from that in a traditional SG-dominated system.Finally,the effects of different QCtrl strategies on transient stability are discussed. 展开更多
关键词 Amplitude-phase response coupling characteristic reactive power control instability mechanism transient stability
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Nonlinear magneto-mechanical-thermo coupling characteristic analysis for transport behaviors of carriers in composite multiferroic piezoelectric semiconductor nanoplates with surface effect
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作者 Wenjun WANG Feng JIN +1 位作者 Tianhu HE Yongbin MA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2022年第9期1323-1338,共16页
In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further i... In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices. 展开更多
关键词 composite multiferroic piezoelectric semiconductor(PS)nanoplate nonlinear multi-field coupling characteristic surface effect screening effect active manipulation of carrier transport
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Spatio-temporal Variability of Northern Hemipheric Sea Level Pressure(SLP)and Precipitation over the Mid-to-Low Reaches of the Yangtze River 被引量:13
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作者 韩雪 魏凤英 +1 位作者 Yves M.TOURRE 董文杰 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2008年第3期458-466,共9页
The spatio-temporal variability of Northern Hemisphere Sea Level Pressure (SLP) and precipitation over the mid-to-low reaches of the Yangtze River (PMLY) is analyzed jointly using the multi-taper/singular value de... The spatio-temporal variability of Northern Hemisphere Sea Level Pressure (SLP) and precipitation over the mid-to-low reaches of the Yangtze River (PMLY) is analyzed jointly using the multi-taper/singular value decomposition method (MTM-SVD). Statistically significant narrow frequency bands are obtained from the local fractional variance (LFV) spectrum. Significant interdecadal (i.e., 16-to-18-year periods) and interannual (i.e., 3-to-6-year periods) signals are identified. Moreover, a significant quasi-biennial signal is identified but only for PMLY data. The spatial joint evolution of patterns obtained for peaks in the LFV spectrum sheds light on relationships between SLP and PMLY: the Arctic Oscillation (AO) modulates the variability of the PMLY while the interannual variability of PMLY is in phase with the Northern Atlantic Oscillation (NAO) and the Northern Pacific Oscillation (NPO). 展开更多
关键词 MTM-SVD coupled spatio-temporal characteristics
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Numerical analysis of seepage flow characteristic of collapse column under the influence of mining 被引量:9
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作者 Ou Subei Wang Lianguo +3 位作者 Wang Peipei Wang Zhansheng Huang Jihui Zhou Donglei 《International Journal of Mining Science and Technology》 SCIE EI 2013年第2期243-250,共8页
Based on the importance of fractured rock mass seepage research, in order to analyze seepage flow characteristics of collapse column under the influence of mining, a method by embedding fractured rock mass flow solid ... Based on the importance of fractured rock mass seepage research, in order to analyze seepage flow characteristics of collapse column under the influence of mining, a method by embedding fractured rock mass flow solid coupling relationship into FLAC3D internal flow models is presented according to fluid-solid coupling theory and strength criterion. A calculation model of numerical analysis was established, and the influences of mining pressure and plastic damage to pore water pressure and seepage vector change rule were studied. The results show that collapse column is the main channel of confined water seepage upward. The impact is not big when the workface is away from the collapse column. But when the workface is nearing a collapse column, there will be a seepage channel on a side near the workface, in which seepage vector and head are comparatively large. With workface pushing through collapse column, the seepage channel transfers to the other side of the column. In addition, when the plastic damage area within the collapse column breaks through, a "pipeline flow" will be formed within the column, and seepage field will change remarkably and the possibility of water bursting will be greater. 展开更多
关键词 Collapse column Fractured rock mass Fluid-solid coupling Seepage characteristic Seepage channel
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A Further Study on an Extended Nonlinear Ocean-Atmosphere Coupled Hydrodynamic Characteristic System and the Abrupt Feature of ENSO Events
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作者 钟青 纪立人 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1992年第2期131-146,共16页
An extended ocean-atmosphere coupled characteristic system including thermodynamic physical processes in ocean mixed layer is formulated in order to describe SST explicitly and remove possible limitation of ocean-atmo... An extended ocean-atmosphere coupled characteristic system including thermodynamic physical processes in ocean mixed layer is formulated in order to describe SST explicitly and remove possible limitation of ocean-atmosphere coupling assumption in hydrodynamic ENSO models. It is revealed that there is a kind of abrupt nonlinear characteristic behaviour, which relates to rapid onset and intermittency of El Nino events, on the second order slow time scale due to the nonlinear interaction between a linear unstable low-frequency primary eigen component of ocean-atmosphere coupled Kelvin wave and its higher order harmonic components under a strong ocean-atmosphere coupling background. And, on the other hand, there is a kind of finite amplitude nonlinear characteristic behaviour on the second order slow time scale due to the nonlinear interaction between the linear unstable primary eigen component and its higher order harmonic components under a weak ocean-atmosphere coupling background in this model system. 展开更多
关键词 A Further Study on an Extended Nonlinear Ocean-Atmosphere Coupled Hydrodynamic Characteristic System and the Abrupt Feature of ENSO Events Nino ENSO
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Time domain finite volume method for the transient response and natural characteristics of structural-acoustic coupling in an enclosed cavity
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作者 XUAN Lingkuan MING Pingjian +2 位作者 ZHANG Wenping JIN Guoyong GONG Jingfeng 《Chinese Journal of Acoustics》 2014年第3期212-227,共16页
A time domain finite volume method(TDFVM)based on wave theory is developed to analyze the transient response and natural characteristics of structural-acoustic coupling problems in an enclosed cavity.In the present ... A time domain finite volume method(TDFVM)based on wave theory is developed to analyze the transient response and natural characteristics of structural-acoustic coupling problems in an enclosed cavity.In the present method,the elastic dynamic equations and acoustic equation in heterogeneous medium are solved in solid domains and fluid domains respectively.The structural-acoustic coupling is implemented according to the continuity condition of the particle velocity along the normal direction and the normal traction equilibrium condition on the interface.Several numerical examples are presented to validate the effectiveness and accuracy of the present TDFVM.Then the effects of water depth on the acoustic and vibration characteristics and the natural characteristics of a structural-acoustic coupling system are analyzed.The numerical results show that the increase of water depth leads to a stronger coupling between the water and structure and the decrease of natural frequencies of coupling system,The computational cost and memory of this method are small and it can be applicable to structural-acoustic coupling problems in the heterogeneous fluid. 展开更多
关键词 Time domain finite volume method for the transient response and natural characteristics of structural-acoustic coupling in an enclosed cavity
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Optimal Operation of Integrated Energy Systems Subject to Coupled Demand Constraints of Electricity and Natural Gas 被引量:17
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作者 Yingjie Qin Lilan Wu +5 位作者 Jiehui Zheng Mengshi Li Zhaoxia Jing Q.H.Wu Xiaoxin Zhou Feng Wei 《CSEE Journal of Power and Energy Systems》 SCIE CSCD 2020年第2期444-457,共14页
This paper proposes a hybrid multi-objective optimization and game-theoretic approach(HMOGTA)to achieve the optimal operation of integrated energy systems(IESs)consisting of electricity and natural gas(E&G)utility... This paper proposes a hybrid multi-objective optimization and game-theoretic approach(HMOGTA)to achieve the optimal operation of integrated energy systems(IESs)consisting of electricity and natural gas(E&G)utility networks,multiple distributed energy stations(DESs),and multiple energy users(EUs).The HMOGTA aims to solve the coordinated operation strategy of the electricity and natural gas networks considering the demand characteristics of DESs and EUs.In the HMOGTA,a hierarchical Stackelberg game model is developed for generating equilibrium strategies of DESs and EUs in each district energy network(DEN).Based on the game results,we obtain the coupling demand constraints of electricity and natural gas(CDCENs)which reflect the relationship between the amounts and prices of electricity and cooling(E&C)that DESs purchase from utility networks.Furthermore,the minimization of conflicting costs of E&G networks considering the CDCENs are solved by a multi-objective optimization method.A case study is conducted on a test IES composed of a 20-node natural gas network,a modified IEEE 30-bus system,and 3 DENs,which verifies the effectiveness of the proposed HMOGTA to realize fair treatment for all participants in the IES. 展开更多
关键词 coupling demand constraints of electricity and natural gas coupling demand characteristics integrated energy system multi-objective optimization Stackelberg game
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An improved single-π equivalent circuit model for on-chip inductors in GaAs process 被引量:1
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作者 Hansheng Wang Weiliang He +1 位作者 Minghui Zhang Lu Tang 《Journal of Semiconductors》 EI CAS CSCD 2017年第11期91-96,共6页
An improved single-π equivalent circuit model for on-chip inductors in the GaAs process is presented in this paper. Considering high order parasites, the model is established by comprising an improved skin effect bra... An improved single-π equivalent circuit model for on-chip inductors in the GaAs process is presented in this paper. Considering high order parasites, the model is established by comprising an improved skin effect branch and a substrate lateral coupling branch. The parameter extraction is based on an improved characteristic function approach and vector fitting method. The model has better simulation than the previous work over the measured data of 2.5r and 4.5r on-chip inductors in the GaAs process. 展开更多
关键词 on-chip inductors GaAs process equivalent circuit model substrate lateral coupling branch improved characteristic function approach vector fitting
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Establishment and solution of the RNC flow network model
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作者 Liying Sun Liang Liu 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2014年第4期227-241,共15页
Refrigerant natural circulation(RNC)system is a closed loop recycling system which is composed of evaporator,condenser,gas pipe and the liquid pipe.The difference in indoor and outdoor temperatures will lead to the re... Refrigerant natural circulation(RNC)system is a closed loop recycling system which is composed of evaporator,condenser,gas pipe and the liquid pipe.The difference in indoor and outdoor temperatures will lead to the refrigerant phase-change,and the gravity difference caused by different heights of condenser and evaporator will make the low boiling point refrigerants carry on natural circulation to realize the indoor heating or cooling.In order to analyze the effect of changes in the RNC system upon the working conditions of the indoor and outdoor units as well as the function of the indoor unit,this paper describes the incidence relations among the various components of the RNC system,and establishes gas–liquid two-phase fluid network mathematical model by using the method of fluid network;besides utilizing the model,it also conducts simulator investigation of coupling characteristics of the RNC system’s refrigeration condition,and makes an analysis of indoor temperature,indoor unit’s air volume,the number of indoor units and the indoor unit capacity and other factors’changes on the coupling characteristics of the RNC system.The results show that under refrigeration conditions,the increase in the air volume of a single indoor unit or room temperature will result in an increase in the cooling capacity of its own indoor units,a decrease in the cooling capacity of other indoor units and a reduction in the total cooling capacity of indoor units of the RNC system;however,the decrease in the outdoor units’inlet temperature will lead to a drop in the evaporation temperature of the system and increase in the cooling capacity. 展开更多
关键词 REFRIGERANTS natural circulation flow network coupling characteristic
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