Superconducting kinetic inductance detectors(KIDs)are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy.As the pixel density and the array siz...Superconducting kinetic inductance detectors(KIDs)are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy.As the pixel density and the array size increase,the electromagnetic crosstalk inevitably becomes a problem that prevents increasing the multiplexing during the development of larger KIDs arrays.In this work,an effective method is introduced to suppress the electromagnetic crosstalk and achieve a compact pixel distribution and small frequency intervals.The electromagnetic crosstalk is first analyzed by simulating the behavior of two neighboring pixels,and the physical distance and the frequency interval are optimized.Then,the arrangement of the pixels on the whole array is redesigned using a genetic algorithm to satisfy the requirements.The simulation results reveal that the normalized electromagnetic crosstalk can be reduced to 0.5%on an 8×8 array.Larger arrays of 16×16 pixels have been fabricated and measured to validate this method,and the results reveal that both the resonance property and survival rate of pixels are improved effectively with this method.This method will be very helpful for designing high-multiplexing KIDs arrays within a limited bandwidth.展开更多
For permanent magnet synchronous machines(PMSMs),accurate inductance is critical for control design and condition monitoring.Owing to magnetic saturation,existing methods require nonlinear saturation model and measure...For permanent magnet synchronous machines(PMSMs),accurate inductance is critical for control design and condition monitoring.Owing to magnetic saturation,existing methods require nonlinear saturation model and measurements from multiple load/current conditions,and the estimation is relying on the accuracy of saturation model and other machine parameters in the model.Speed harmonic produced by harmonic currents is inductance-dependent,and thus this paper explores the use of magnitude and phase angle of the speed harmonic for accurate inductance estimation.Two estimation models are built based on either the magnitude or phase angle,and the inductances can be from d-axis voltage and the magnitude or phase angle,in which the filter influence in harmonic extraction is considered to ensure the estimation performance.The inductances can be estimated from the measurements under one load condition,which is free of saturation model.Moreover,the inductance estimation is robust to the change of other machine parameters.The proposed approach can effectively improve estimation accuracy especially under the condition with low current magnitude.Experiments and comparisons are conducted on a test PMSM to validate the proposed approach.展开更多
Small multi-turn coil devices are used with the transient electromagnetic method （TEM） in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and f...Small multi-turn coil devices are used with the transient electromagnetic method （TEM） in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and for detecting shallow geological targets in environmental and engineering fields. However, the equipment involved has strong mutual inductance coupling, which causes a lengthy turn-off time and a deep “blind zone”. This study proposes a new transmitter device with a conical-shape source and derives the radius formula of each coil and the mutual inductance coefficient of the cone. According to primary field characteristics, results of the two fields created, calculation of the conical-shaped source in a uniform medium using theoretical analysis, and a comparison of the inductance of the new device with that of the multi-turn coil, show that inductance of the multi-turn coil is nine times greater than that of the conical source with the same equivalent magnetic moment of 926.1 A·m2. This indicates that the new source leads to a much shallower “blind zone.” Furthermore, increasing the bottom radius and turn of the cone creates a larger mutual inductance but increasing the cone height results in a lower mutual inductance. Using the superposition principle, the primary and secondary magnetic fields for a conical source in a homogeneous medium are calculated; results indicate that the magnetic behavior of the cone is the same as that of the multi-turn coils, but the transient responses of the secondary field and the total field are more stronger than those of the multi-turn coils. To study the transient response characteristics using a cone-shaped source in a layered earth, a numerical filtering algorithm is then developed using the fast Hankel transform and the improved cosine transform, again using the superposition principle. During development, an average apparent resistivity inverted from the induced electromotive force using each coil is defined to represent the comprehensive resistivity of the conical source. To verify the forward calculation method, the transient responses of H type models and KH type models are calculated, and data are inverted using a “smoke ring” inversion. The results of inversion have good agreement with original models and show that the forward calculation method is effective. The results of this study provide an option for solving the problem of a deep “blind zone” and also provide a theoretical indicator for further research.展开更多
An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expre...An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expressions is firstly developed to calculate the self-inductance of a single layer, and then numerical calcu lation of the mutual inductance between two layers is introduced. Using the presented computation method, the inductance of a solenoid designed in the experiment is successfully calculated （4.30 mH）, which has a difference of less than 1% from the experimental data.展开更多
We study the quantization of mesoscopic inductance coupling circuit and discuss its time evolution. Bymeans of the thermal field dynamics theory we study the quantum fluctuation of the system at finite temperature.
We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coh...We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coherent state under the effect of external source.We find that the squeezing amplitude parameter is relative to the parameters of circuit and the mutual-inductance coefficient in the existence of dissipation.When the circuit has no dissipation or there is complete coupling between two meshes,the squeezing amplitude parameter only depends on the capacitance's ratio.展开更多
Magnetorheological(MR)materials are a class of smart material,whose the mechanical/rheological state can be controlled under a magnetic field.Magnetorheological materials are typically fluids,gels,or elastomers.In thi...Magnetorheological(MR)materials are a class of smart material,whose the mechanical/rheological state can be controlled under a magnetic field.Magnetorheological materials are typically fluids,gels,or elastomers.In this study,anisotropic and isotropic magneto-rheological elastomer(MRE)samples were fabricated using a silicone rubber matrix with carbonyl iron particles as filler particles.The magnetic field-dependent inductance properties of these samples were studied using inductors specially designed for the analysis.The effect of the filler particle content,fabrication conditions,and inductance properties were characterized using a self-built system in both constant and transient magnetic fields.These factors show a significant effect on the inductance properties of the MRE inductor under an applied magnetic field.The anisotropic MRE inductor was more sensitive than the inductor based on an isotropic MRE.Owing to the presence of a constant magnetic field,the inductance value of the MRE inductor decreased with an increase in the external magnetic field.An attempt in elucidation of the mechanism is reported here.This study may enable the MRE to be widely used in practical applications such as monitoring magnetic field or detecting the filler particle content inside MR materials.展开更多
This paper deals with an analytical method to effectively calculate the inductance of an exterior-rotor switched reluctance motor(SRM),which evaluates the winding inductance of both the active section and the end sect...This paper deals with an analytical method to effectively calculate the inductance of an exterior-rotor switched reluctance motor(SRM),which evaluates the winding inductance of both the active section and the end section,accounting for the influence of core saturation.According to the inductance calculated by the analytical model,the flux linkage table and torque table can be established,and the steady state performance such as phase current,flux linkage,copper loss and core loss can be predicted.Effectiveness of this method is verified by the finite element method as well as by experimental results of a 12/8 SRM prototype.展开更多
Inductance asymmetry,which is brought by inherent asymmetric parameters,manufacture tolerance,winding fault,cables with unequal lengths,etc.,of permanent-magnet synchronous machines(PMSMs)can cause current harmonics a...Inductance asymmetry,which is brought by inherent asymmetric parameters,manufacture tolerance,winding fault,cables with unequal lengths,etc.,of permanent-magnet synchronous machines(PMSMs)can cause current harmonics and inaccurate position estimation.This paper proposes an enhanced fundamental model based sensorless control strategy for PMSMs with asymmetric inductances.The proportional-integral-resonant current regulator is introduced to reduce the second-order harmonics of currents,but there are still negative sequence components in the estimated back-electromotive forces(EMFs),which can cause the position estimated error.Differing from conventional methods in which negative sequences are filtered out before the phase-locked loop(PLL)module,the proposed method directly applies the estimated back-EMF with negative sequences as the reference input of PLL.An improved PLL with a bi-quad filter is proposed to attenuate the arising second harmonic position error and heighten the steady-state accuracy.Then,this position error is used for asymmetric inductance identification and its result is utilized to update the observer model.Furthermore,the dynamic performance is improved by the output limitation on the bi-quad filter as well as the implementation of a fast-locking technique in the PLL.The effectiveness of the proposed scheme is verified by experimental results.展开更多
Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polyg...Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polygons.Based on the Biot-Savart law,the method calculates mutual inductance by dividing a polygonal coil into finite wires,and expresses the magnetic induction intensity generated by the excitation coil as a function of the spatial position of each vertex of the coil.The calculation method of the feasible region of the objective function is updated and the calculation process is simplified,so the calculation accuracy is improved.For octagon coils arbitrarily positioned in space,the accuracy of the algorithm is verified by the simulation and experiment.展开更多
Low-frequency double-resonance quartz crystal oscillator was developed with active inductance circuit aiming the start-up of stable oscillation of tuning fork-type quartz crystal resonator at 32.768 kHz within 0.37 ms...Low-frequency double-resonance quartz crystal oscillator was developed with active inductance circuit aiming the start-up of stable oscillation of tuning fork-type quartz crystal resonator at 32.768 kHz within 0.37 ms. The initial oscillation is triggered by a part of crystal oscillator forming a CR oscillator. The negative resistance ranges to 4 MΩ at gmf of 4.1 μA/V. In a limited frequency range, the circuit shows negative reactance Ccci = -3.4 pF equivalent to inductance Lcc = 9.8 H. The Allan standard deviation indicated 10-11 to 10-10, showing high stability comparable to general quartz crystal oscillator.展开更多
New electronically-controllable lossless grounded and floating inductance simulation circuits have been proposed employing Voltage Differencing Transconductance Amplifiers (VDTA). The proposed grounded inductance (GI)...New electronically-controllable lossless grounded and floating inductance simulation circuits have been proposed employing Voltage Differencing Transconductance Amplifiers (VDTA). The proposed grounded inductance (GI) circuit employs a single VDTA and one grounded capacitor whereas the floating inductance (FI) circuit employs two VDTAs and one grounded capacitor. The workability of the new circuits has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.展开更多
New Voltage Differencing Differential Input Buffered Amplifier (VD-DIBA) based lossless grounded and floating inductance simulation circuits have been proposed. The proposed grounded simulated inductance circuit emplo...New Voltage Differencing Differential Input Buffered Amplifier (VD-DIBA) based lossless grounded and floating inductance simulation circuits have been proposed. The proposed grounded simulated inductance circuit employs a single VD-DIBA, one floating resistance and one grounded capacitor. The floating simulated inductance (FI) circuits employ two VD-DIBAs with two passive components (one floating resistance and one grounded capacitor). The circuit for grounded inductance does not require any realization conditions where as in case of floating inductance circuits, a single matching condition is needed. Simulation results demonstrating the applications of the new simulated inductors using CMOS VD-DIBAs have been included to confirm the workability of the new circuits.展开更多
A configuration using current feedback amplifiers AD844 and multiplier AD534 has been presented, which is capable of realizing Voltage Controlled Floating Inductance (proportional and in-verse proportional). The appli...A configuration using current feedback amplifiers AD844 and multiplier AD534 has been presented, which is capable of realizing Voltage Controlled Floating Inductance (proportional and in-verse proportional). The application of band pass filter in Figure 4(a), notch filter in Figure 5(a) and Hartley oscillator in Figure 6(a) and simulation result in Figures 4(b)-(d), Figures 5(b)-(d), Figures 6(b)-(d) shows the workability of proposed configuration.展开更多
Three-dimensional(3D) single-layer microcoils have always been a key element for electromagnetic systems;but they lack an easy and accurate method to calculate the inductance value for their complex 3D micro-structure...Three-dimensional(3D) single-layer microcoils have always been a key element for electromagnetic systems;but they lack an easy and accurate method to calculate the inductance value for their complex 3D micro-structures. This paper employed a curve-fitting process to obtain the associated equation for the inductance value and geometric parameters based on the simulation results. The correction factors regarding helical pitch and wire diameter were reviewed,which are used for compensation in the Nagaoka formula. The simulation process numerically simulated the performance of the 3D microcoils using a FEM electro-magnetic-coupled analysis method. Comparison of the simulated inductance value and the Nagaoka formula was undertaken,which shows that the helical pitch and wire diameter contribute a main role in the calculation error. The derived formula was expressed in a concise form to precisely calculate the inductance value of 3D microsolenoids with single-layer coils.展开更多
The resonant frequency of metamaterials structured with split ring resonator(SRR) meta-atoms is determined primarily through the capacitance and inductance of the individual meta-atoms. Two designs that vary inductanc...The resonant frequency of metamaterials structured with split ring resonator(SRR) meta-atoms is determined primarily through the capacitance and inductance of the individual meta-atoms. Two designs that vary inductance incrementally were modeled, simulated, fabricated, and tested to investigate the role inductance plays in metamaterial designs. The designs consisted of strategically adding sections to the SRR to increase the inductance, but in a manner that minimized capacitance variations. Each design showed a shift in resonant frequency that was proportional to the length of the added section. As the length of each section was increased, the resonant frequency shifted from 2.78 GHz to 2.18 GHz.展开更多
The resistance and inductance of a wire array during an implosion are very important parameters of interest to：researchers. A variety of inductances and resistances directly affect the kinetic energy and resistance h...The resistance and inductance of a wire array during an implosion are very important parameters of interest to：researchers. A variety of inductances and resistances directly affect the kinetic energy and resistance heat energy coupled from a pulsed-power generator. In this paper, the inductance and resistance of a planar wire array during the Z-pinch process are analyzed. The inductance is calculated from the data obtained by a time-resolved soft X-ray framed camera, while the resistance is calculated through the voltage and the current of the wire array load combined with the variety of the inductance. The results show that the resistance of the load increases with the development of the implosion, and reaches its maximum at 0.29 ± 0.16Ω near the pinched time.展开更多
Transformers are required to demonstrate the ability to withstand short circuit currents.Over currents caused by short circuit can give rise to windings deformation.In this paper,a novel method is proposed to monitor ...Transformers are required to demonstrate the ability to withstand short circuit currents.Over currents caused by short circuit can give rise to windings deformation.In this paper,a novel method is proposed to monitor the state of transformer windings,which is achieved through on-line detecting the leakage inductance of the windings.Specifically,the mathematical model is established for online identifying the leakage inductance of the windings by applying least square algorithm(LSA) to the equivalent circuit equations.The effect of measurement and model inaccuracy on the identification error is analyzed,and the corrected model is also given to decrease these adverse effect on the results.Finally,dynamic test is carried out to verify our method.The test results clearly show that our method is very accurate even under the fluctuation of load or power factor.Therefore,our method can be effectively used to on-line detect the windings deformation.展开更多
We design and fabricateλ/2 coplanar waveguide NbN resonators,the thickness and length of which are only several nanometers and hundred microns,respectively.The quality factor of such compact resonators can reach up t...We design and fabricateλ/2 coplanar waveguide NbN resonators,the thickness and length of which are only several nanometers and hundred microns,respectively.The quality factor of such compact resonators can reach up to 7.5×10~4 at single photon power level at 30 m K with the resonance frequency around 6.835 GHz.In order to tune the resonant frequency,the resonator is terminated to the ground with a dc-SQUID.By tuning the magnetic flux in the dc-SQUID,the effective inductance of the dc-SQUID is varied,which leads to the change in the resonant frequency of the resonator.The tunability range is more than 30 MHz and the quality factor is about 3×10~3.These compact and tunable NbN resonators have potential applications in the quantum information processing,such as in the precision measurement,coupling and/or reading out the quantum states of qubits.展开更多
By solving the basic equations of magnetic field in the anisotropic magnetic mediain which the tensor μik is symmetric,an integral formula for anisotropic vector potential A isobtained.By which the characteristic for...By solving the basic equations of magnetic field in the anisotropic magnetic mediain which the tensor μik is symmetric,an integral formula for anisotropic vector potential A isobtained.By which the characteristic formulae for self and mutual inductances are derived inscalar and tensor forms,and their transformation formula are also derived.Finally,the formulais checked by practical examples.展开更多
基金supported by the National Key Research and Development Program of China(2023YFC2206601)the National Natural Science Foundation of China(12273024,62205211)the Science and Technology Commission of Shanghai Municipality(23010503900,22590780100).
文摘Superconducting kinetic inductance detectors(KIDs)are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy.As the pixel density and the array size increase,the electromagnetic crosstalk inevitably becomes a problem that prevents increasing the multiplexing during the development of larger KIDs arrays.In this work,an effective method is introduced to suppress the electromagnetic crosstalk and achieve a compact pixel distribution and small frequency intervals.The electromagnetic crosstalk is first analyzed by simulating the behavior of two neighboring pixels,and the physical distance and the frequency interval are optimized.Then,the arrangement of the pixels on the whole array is redesigned using a genetic algorithm to satisfy the requirements.The simulation results reveal that the normalized electromagnetic crosstalk can be reduced to 0.5%on an 8×8 array.Larger arrays of 16×16 pixels have been fabricated and measured to validate this method,and the results reveal that both the resonance property and survival rate of pixels are improved effectively with this method.This method will be very helpful for designing high-multiplexing KIDs arrays within a limited bandwidth.
基金supported in part by the National Natural Science Foundation of China(62473387)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP241)the Department of Science and Technology of Guangdong Province(2021QN020085)。
文摘For permanent magnet synchronous machines(PMSMs),accurate inductance is critical for control design and condition monitoring.Owing to magnetic saturation,existing methods require nonlinear saturation model and measurements from multiple load/current conditions,and the estimation is relying on the accuracy of saturation model and other machine parameters in the model.Speed harmonic produced by harmonic currents is inductance-dependent,and thus this paper explores the use of magnitude and phase angle of the speed harmonic for accurate inductance estimation.Two estimation models are built based on either the magnitude or phase angle,and the inductances can be from d-axis voltage and the magnitude or phase angle,in which the filter influence in harmonic extraction is considered to ensure the estimation performance.The inductances can be estimated from the measurements under one load condition,which is free of saturation model.Moreover,the inductance estimation is robust to the change of other machine parameters.The proposed approach can effectively improve estimation accuracy especially under the condition with low current magnitude.Experiments and comparisons are conducted on a test PMSM to validate the proposed approach.
基金supported by the National Natural Science Foundation of China(Nos.41564001 and 41572185)the Natural Science Foundation of Jiangxi Province(No.20151BAB203045)
文摘Small multi-turn coil devices are used with the transient electromagnetic method （TEM） in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and for detecting shallow geological targets in environmental and engineering fields. However, the equipment involved has strong mutual inductance coupling, which causes a lengthy turn-off time and a deep “blind zone”. This study proposes a new transmitter device with a conical-shape source and derives the radius formula of each coil and the mutual inductance coefficient of the cone. According to primary field characteristics, results of the two fields created, calculation of the conical-shaped source in a uniform medium using theoretical analysis, and a comparison of the inductance of the new device with that of the multi-turn coil, show that inductance of the multi-turn coil is nine times greater than that of the conical source with the same equivalent magnetic moment of 926.1 A·m2. This indicates that the new source leads to a much shallower “blind zone.” Furthermore, increasing the bottom radius and turn of the cone creates a larger mutual inductance but increasing the cone height results in a lower mutual inductance. Using the superposition principle, the primary and secondary magnetic fields for a conical source in a homogeneous medium are calculated; results indicate that the magnetic behavior of the cone is the same as that of the multi-turn coils, but the transient responses of the secondary field and the total field are more stronger than those of the multi-turn coils. To study the transient response characteristics using a cone-shaped source in a layered earth, a numerical filtering algorithm is then developed using the fast Hankel transform and the improved cosine transform, again using the superposition principle. During development, an average apparent resistivity inverted from the induced electromotive force using each coil is defined to represent the comprehensive resistivity of the conical source. To verify the forward calculation method, the transient responses of H type models and KH type models are calculated, and data are inverted using a “smoke ring” inversion. The results of inversion have good agreement with original models and show that the forward calculation method is effective. The results of this study provide an option for solving the problem of a deep “blind zone” and also provide a theoretical indicator for further research.
文摘An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expressions is firstly developed to calculate the self-inductance of a single layer, and then numerical calcu lation of the mutual inductance between two layers is introduced. Using the presented computation method, the inductance of a solenoid designed in the experiment is successfully calculated （4.30 mH）, which has a difference of less than 1% from the experimental data.
文摘We study the quantization of mesoscopic inductance coupling circuit and discuss its time evolution. Bymeans of the thermal field dynamics theory we study the quantum fluctuation of the system at finite temperature.
文摘We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coherent state under the effect of external source.We find that the squeezing amplitude parameter is relative to the parameters of circuit and the mutual-inductance coefficient in the existence of dissipation.When the circuit has no dissipation or there is complete coupling between two meshes,the squeezing amplitude parameter only depends on the capacitance's ratio.
基金Project(cstc2019jcyj-msxm X0005)supported by General Program of Chongqing Natural Science Foundation,ChinaProject(51905062)supported by the National Natural Science Foundation of China。
文摘Magnetorheological(MR)materials are a class of smart material,whose the mechanical/rheological state can be controlled under a magnetic field.Magnetorheological materials are typically fluids,gels,or elastomers.In this study,anisotropic and isotropic magneto-rheological elastomer(MRE)samples were fabricated using a silicone rubber matrix with carbonyl iron particles as filler particles.The magnetic field-dependent inductance properties of these samples were studied using inductors specially designed for the analysis.The effect of the filler particle content,fabrication conditions,and inductance properties were characterized using a self-built system in both constant and transient magnetic fields.These factors show a significant effect on the inductance properties of the MRE inductor under an applied magnetic field.The anisotropic MRE inductor was more sensitive than the inductor based on an isotropic MRE.Owing to the presence of a constant magnetic field,the inductance value of the MRE inductor decreased with an increase in the external magnetic field.An attempt in elucidation of the mechanism is reported here.This study may enable the MRE to be widely used in practical applications such as monitoring magnetic field or detecting the filler particle content inside MR materials.
文摘This paper deals with an analytical method to effectively calculate the inductance of an exterior-rotor switched reluctance motor(SRM),which evaluates the winding inductance of both the active section and the end section,accounting for the influence of core saturation.According to the inductance calculated by the analytical model,the flux linkage table and torque table can be established,and the steady state performance such as phase current,flux linkage,copper loss and core loss can be predicted.Effectiveness of this method is verified by the finite element method as well as by experimental results of a 12/8 SRM prototype.
基金supported in part by the National Key R&D Program of China under Grant 2019YFB1503700in part by the National Natural Science Foundation of China under Grant 51977191。
文摘Inductance asymmetry,which is brought by inherent asymmetric parameters,manufacture tolerance,winding fault,cables with unequal lengths,etc.,of permanent-magnet synchronous machines(PMSMs)can cause current harmonics and inaccurate position estimation.This paper proposes an enhanced fundamental model based sensorless control strategy for PMSMs with asymmetric inductances.The proportional-integral-resonant current regulator is introduced to reduce the second-order harmonics of currents,but there are still negative sequence components in the estimated back-electromotive forces(EMFs),which can cause the position estimated error.Differing from conventional methods in which negative sequences are filtered out before the phase-locked loop(PLL)module,the proposed method directly applies the estimated back-EMF with negative sequences as the reference input of PLL.An improved PLL with a bi-quad filter is proposed to attenuate the arising second harmonic position error and heighten the steady-state accuracy.Then,this position error is used for asymmetric inductance identification and its result is utilized to update the observer model.Furthermore,the dynamic performance is improved by the output limitation on the bi-quad filter as well as the implementation of a fast-locking technique in the PLL.The effectiveness of the proposed scheme is verified by experimental results.
文摘Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polygons.Based on the Biot-Savart law,the method calculates mutual inductance by dividing a polygonal coil into finite wires,and expresses the magnetic induction intensity generated by the excitation coil as a function of the spatial position of each vertex of the coil.The calculation method of the feasible region of the objective function is updated and the calculation process is simplified,so the calculation accuracy is improved.For octagon coils arbitrarily positioned in space,the accuracy of the algorithm is verified by the simulation and experiment.
文摘Low-frequency double-resonance quartz crystal oscillator was developed with active inductance circuit aiming the start-up of stable oscillation of tuning fork-type quartz crystal resonator at 32.768 kHz within 0.37 ms. The initial oscillation is triggered by a part of crystal oscillator forming a CR oscillator. The negative resistance ranges to 4 MΩ at gmf of 4.1 μA/V. In a limited frequency range, the circuit shows negative reactance Ccci = -3.4 pF equivalent to inductance Lcc = 9.8 H. The Allan standard deviation indicated 10-11 to 10-10, showing high stability comparable to general quartz crystal oscillator.
文摘New electronically-controllable lossless grounded and floating inductance simulation circuits have been proposed employing Voltage Differencing Transconductance Amplifiers (VDTA). The proposed grounded inductance (GI) circuit employs a single VDTA and one grounded capacitor whereas the floating inductance (FI) circuit employs two VDTAs and one grounded capacitor. The workability of the new circuits has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.
文摘New Voltage Differencing Differential Input Buffered Amplifier (VD-DIBA) based lossless grounded and floating inductance simulation circuits have been proposed. The proposed grounded simulated inductance circuit employs a single VD-DIBA, one floating resistance and one grounded capacitor. The floating simulated inductance (FI) circuits employ two VD-DIBAs with two passive components (one floating resistance and one grounded capacitor). The circuit for grounded inductance does not require any realization conditions where as in case of floating inductance circuits, a single matching condition is needed. Simulation results demonstrating the applications of the new simulated inductors using CMOS VD-DIBAs have been included to confirm the workability of the new circuits.
文摘A configuration using current feedback amplifiers AD844 and multiplier AD534 has been presented, which is capable of realizing Voltage Controlled Floating Inductance (proportional and in-verse proportional). The application of band pass filter in Figure 4(a), notch filter in Figure 5(a) and Hartley oscillator in Figure 6(a) and simulation result in Figures 4(b)-(d), Figures 5(b)-(d), Figures 6(b)-(d) shows the workability of proposed configuration.
基金supported by the National Science Foundation of China under the Grant No.61176113 and 51335008the Special-funded program on national key scientific instruments and equipment development of China under the Grant No.2012YQ12004706the Program for Changjiang Scholars and Innovative Research Team in University(IRT1033)。
文摘Three-dimensional(3D) single-layer microcoils have always been a key element for electromagnetic systems;but they lack an easy and accurate method to calculate the inductance value for their complex 3D micro-structures. This paper employed a curve-fitting process to obtain the associated equation for the inductance value and geometric parameters based on the simulation results. The correction factors regarding helical pitch and wire diameter were reviewed,which are used for compensation in the Nagaoka formula. The simulation process numerically simulated the performance of the 3D microcoils using a FEM electro-magnetic-coupled analysis method. Comparison of the simulated inductance value and the Nagaoka formula was undertaken,which shows that the helical pitch and wire diameter contribute a main role in the calculation error. The derived formula was expressed in a concise form to precisely calculate the inductance value of 3D microsolenoids with single-layer coils.
文摘The resonant frequency of metamaterials structured with split ring resonator(SRR) meta-atoms is determined primarily through the capacitance and inductance of the individual meta-atoms. Two designs that vary inductance incrementally were modeled, simulated, fabricated, and tested to investigate the role inductance plays in metamaterial designs. The designs consisted of strategically adding sections to the SRR to increase the inductance, but in a manner that minimized capacitance variations. Each design showed a shift in resonant frequency that was proportional to the length of the added section. As the length of each section was increased, the resonant frequency shifted from 2.78 GHz to 2.18 GHz.
基金supported by National Natural Science Fundation of China(No.10905047)
文摘The resistance and inductance of a wire array during an implosion are very important parameters of interest to：researchers. A variety of inductances and resistances directly affect the kinetic energy and resistance heat energy coupled from a pulsed-power generator. In this paper, the inductance and resistance of a planar wire array during the Z-pinch process are analyzed. The inductance is calculated from the data obtained by a time-resolved soft X-ray framed camera, while the resistance is calculated through the voltage and the current of the wire array load combined with the variety of the inductance. The results show that the resistance of the load increases with the development of the implosion, and reaches its maximum at 0.29 ± 0.16Ω near the pinched time.
基金This work was supported in part by National Natural Science Foundation of China(No.50577050).
文摘Transformers are required to demonstrate the ability to withstand short circuit currents.Over currents caused by short circuit can give rise to windings deformation.In this paper,a novel method is proposed to monitor the state of transformer windings,which is achieved through on-line detecting the leakage inductance of the windings.Specifically,the mathematical model is established for online identifying the leakage inductance of the windings by applying least square algorithm(LSA) to the equivalent circuit equations.The effect of measurement and model inaccuracy on the identification error is analyzed,and the corrected model is also given to decrease these adverse effect on the results.Finally,dynamic test is carried out to verify our method.The test results clearly show that our method is very accurate even under the fluctuation of load or power factor.Therefore,our method can be effectively used to on-line detect the windings deformation.
基金Project partially supported by the National Key R&D Program of China(Grant No.2016YFA0301801)the National Natural Science Foundation of China(Grant Nos.11474154 and 61521001)+1 种基金PAPD,Dengfeng Project B of Nanjing Universitythe Fundamental Research Funds for the Central Universities,China(Grant No.14380134)。
文摘We design and fabricateλ/2 coplanar waveguide NbN resonators,the thickness and length of which are only several nanometers and hundred microns,respectively.The quality factor of such compact resonators can reach up to 7.5×10~4 at single photon power level at 30 m K with the resonance frequency around 6.835 GHz.In order to tune the resonant frequency,the resonator is terminated to the ground with a dc-SQUID.By tuning the magnetic flux in the dc-SQUID,the effective inductance of the dc-SQUID is varied,which leads to the change in the resonant frequency of the resonator.The tunability range is more than 30 MHz and the quality factor is about 3×10~3.These compact and tunable NbN resonators have potential applications in the quantum information processing,such as in the precision measurement,coupling and/or reading out the quantum states of qubits.
文摘By solving the basic equations of magnetic field in the anisotropic magnetic mediain which the tensor μik is symmetric,an integral formula for anisotropic vector potential A isobtained.By which the characteristic formulae for self and mutual inductances are derived inscalar and tensor forms,and their transformation formula are also derived.Finally,the formulais checked by practical examples.
