In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a n...In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PWA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating representation.Finally, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.展开更多
Two simple voltage-controlled-oscillators (VCO) with linear tuning laws employing only a single current feedback operational amplifier (CFOA) in conjunction with two analog multipliers (AM) have been highlighted. The ...Two simple voltage-controlled-oscillators (VCO) with linear tuning laws employing only a single current feedback operational amplifier (CFOA) in conjunction with two analog multipliers (AM) have been highlighted. The workability of the presented VCOs has been demonstrated by experimental results based upon AD844 type CFOAs and AD534 type AMs.展开更多
One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltag...One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.展开更多
A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a...A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.展开更多
A new non-inverting RC active differentiator network base on a current feedback amplifier and using a grounded capacitor is described. Small time constant can be achieved by adjusting a single grounded resistor. Becau...A new non-inverting RC active differentiator network base on a current feedback amplifier and using a grounded capacitor is described. Small time constant can be achieved by adjusting a single grounded resistor. Because the output impedance of the CFA is very low, the output terminal of the proposed circuit can be directly connected to the next stage. Experimental results that confirm theoretical analysis are presented.展开更多
There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The c...There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The control system for the plasma current and horizontal position control has been designed and showed satisfactory results with the feedback control of multivari- able feedforward-decoupling and var-parameter PID controller to simultaneously modulate power supplies. The design and analysls of the control system is presented.展开更多
We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the thre...We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.展开更多
This paper presents improvement tests based in a feedback-current controller designed to Tracking Maximum Power Point in photovoltaic system (MPPT-PV). Previously, a version was developed exhibiting results satisfacto...This paper presents improvement tests based in a feedback-current controller designed to Tracking Maximum Power Point in photovoltaic system (MPPT-PV). Previously, a version was developed exhibiting results satisfactory in simulation and through of a low cost prototype. Now, using a sophisticated physical model of solar cell available in PSIM program is shown other cases, considering variations both irradiation and temperature to evaluate successfully the controller. The results show that its system is suitable under dynamical changing atmospheric conditions operating with effectiveness acceptable.展开更多
In this study,on the basis of the results of the European Centre for Medium-Range Weather Forecasts Ocean Reanalysis System 4,the response of equatorial ocean currents and their roles during the peak phase of the Indi...In this study,on the basis of the results of the European Centre for Medium-Range Weather Forecasts Ocean Reanalysis System 4,the response of equatorial ocean currents and their roles during the peak phase of the Indian Ocean Dipole(IOD)are comprehensively explored.During the IOD peak season,a series of ocean responses emerge.First,significant meridional divergence in the surface layer and convergence in the subsurface layer are found in the equatorial region.The equatorial easterly winds and offequatorial wind curl anomalies are found to be responsible for the divergence at 55°–80°E and the convergence at 70°–90°E.Second,the meridional divergence and convergence are found to favor a weakened Wyrtki jet(WJ)in the surface layer and an enhanced Equatorial Undercurrent(EUC)in the subsurface layer,respectively.Therefore,these ocean responses provide ocean positive feedback that sustains the IOD peak as the weakened WJ and enhanced EUC help maintain the zonal temperature gradient.Additionally,heat budget analyses indicate that the weakened WJ favors sea surface temperature anomaly warming in the western Indian Ocean,whereas the enhanced EUC maintains the sea surface temperature anomaly cooling in the eastern Indian Ocean.展开更多
The study of controlling high-current proton beam halo-chaos has become a key concerned issue for manyimportant applications. In this paper, time-delayed feedback control method is proposed for beam halo-chaos. Partic...The study of controlling high-current proton beam halo-chaos has become a key concerned issue for manyimportant applications. In this paper, time-delayed feedback control method is proposed for beam halo-chaos. Particle incell simulation results show that the method is very effective and has some advantages for high-current beam experimentsand engineering.展开更多
基金supported in part by the National Natural Science Foundation of China (62222310, U1813201, 61973131, 62033008)the Research Fund for the Taishan Scholar Project of Shandong Province of China+2 种基金the NSFSD(ZR2022ZD34)Japan Society for the Promotion of Science (21K04129)Fujian Outstanding Youth Science Fund (2020J06022)。
文摘In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PWA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating representation.Finally, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.
文摘Two simple voltage-controlled-oscillators (VCO) with linear tuning laws employing only a single current feedback operational amplifier (CFOA) in conjunction with two analog multipliers (AM) have been highlighted. The workability of the presented VCOs has been demonstrated by experimental results based upon AD844 type CFOAs and AD534 type AMs.
文摘One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.
文摘A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.
文摘A new non-inverting RC active differentiator network base on a current feedback amplifier and using a grounded capacitor is described. Small time constant can be achieved by adjusting a single grounded resistor. Because the output impedance of the CFA is very low, the output terminal of the proposed circuit can be directly connected to the next stage. Experimental results that confirm theoretical analysis are presented.
文摘There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The control system for the plasma current and horizontal position control has been designed and showed satisfactory results with the feedback control of multivari- able feedforward-decoupling and var-parameter PID controller to simultaneously modulate power supplies. The design and analysls of the control system is presented.
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB632801 and 2013CB632803the National Natural Science Foundation of China under Grant Nos 61435014,61306058 and 61274094the Beijing Natural Science Foundation under Grant No 4144086
文摘We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.
文摘This paper presents improvement tests based in a feedback-current controller designed to Tracking Maximum Power Point in photovoltaic system (MPPT-PV). Previously, a version was developed exhibiting results satisfactory in simulation and through of a low cost prototype. Now, using a sophisticated physical model of solar cell available in PSIM program is shown other cases, considering variations both irradiation and temperature to evaluate successfully the controller. The results show that its system is suitable under dynamical changing atmospheric conditions operating with effectiveness acceptable.
基金the National Key R&D Program of China(No.2019YFA0606701)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA20060502)+6 种基金the National Natural Science Foundation of China(Nos.42076020,41776023 and 91958202)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0306)the Innovation Academy of South China Sea Ecology and Environmental Engineering of the Chinese Academy of Sciences(No.ISEE2018PY06)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-XH-2019-2)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020340)the Rising Star Foundation of the SCSIO(No.NHXX2018WL0201)the Independent Research Project Program of the State Key Laboratory of Tropical Oceanography(No.LTOZZ2101)。
文摘In this study,on the basis of the results of the European Centre for Medium-Range Weather Forecasts Ocean Reanalysis System 4,the response of equatorial ocean currents and their roles during the peak phase of the Indian Ocean Dipole(IOD)are comprehensively explored.During the IOD peak season,a series of ocean responses emerge.First,significant meridional divergence in the surface layer and convergence in the subsurface layer are found in the equatorial region.The equatorial easterly winds and offequatorial wind curl anomalies are found to be responsible for the divergence at 55°–80°E and the convergence at 70°–90°E.Second,the meridional divergence and convergence are found to favor a weakened Wyrtki jet(WJ)in the surface layer and an enhanced Equatorial Undercurrent(EUC)in the subsurface layer,respectively.Therefore,these ocean responses provide ocean positive feedback that sustains the IOD peak as the weakened WJ and enhanced EUC help maintain the zonal temperature gradient.Additionally,heat budget analyses indicate that the weakened WJ favors sea surface temperature anomaly warming in the western Indian Ocean,whereas the enhanced EUC maintains the sea surface temperature anomaly cooling in the eastern Indian Ocean.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10247005,70071047,and 19875080
文摘The study of controlling high-current proton beam halo-chaos has become a key concerned issue for manyimportant applications. In this paper, time-delayed feedback control method is proposed for beam halo-chaos. Particle incell simulation results show that the method is very effective and has some advantages for high-current beam experimentsand engineering.