Recently, a number of architectures have been proposed for the design of future pulsed power Z-pinch drivers 1 . In the architectures nonuniform transmission lines were used to combine the outputs of several-hundred t...
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ISBN:
(纸本)9781479927142
Recently, a number of architectures have been proposed for the design of future pulsed power Z-pinch drivers 1 . In the architectures nonuniform transmission lines were used to combine the outputs of several-hundred terawatt-level pulse generators to produce a petawatt-level pulse. In general, people obtained the output voltage from a nonuniform transmission line by considering the nonuniform line as a cascaded multiple-section line and then calculating it with the circuit simulation codes such as PSpice or TLCODE. We also treated the nonuniform line as a cascaded multiple-section line, but analyzed it with an analytical method. We found that a mathematical expression of the output voltage from a nonuniform line could be deduced if the impedance profile of the nonuniform line changes continuously and monotonically and each line section of the cascaded multiple-section line is short enough. The output voltage consists of one primary component called first arriving wave and numerous double-reflection components. In comparison with the input voltage wave, the first arriving wave is the same in wave shape and proportional to (Z out /Z in ) 1/2 in amplitude, where Z out and Z in are the output impedance and the input impedance of the nonuniform line, respectively. It was shown that the double reflection components not only lower the output voltage, but also compress the output voltage pulse. The waveform of the output voltage obtained using our mathematical expression is fully overlapping with that obtained from the circuit simulation using PSpice, which indicates that our mathematical expression is correct.
A mathematical expression of the output voltage from a nonuniform line was deduced by investigating the transient response of a cascaded multiple-section line to an input voltage of half-sine shape that is close to th...
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A mathematical expression of the output voltage from a nonuniform line was deduced by investigating the transient response of a cascaded multiple-section line to an input voltage of half-sine shape that is close to the wave shape of the pulse voltage for Z-pinch. The correctness of the mathematical expression was verified by comparing the result from the mathematical expression with that from circuit simulation using PSpice code. The high-pass and pulse-compression characteristics of a nonuniform line were further clarified by the analytical analysis of the mathematical expression.
This paper discusses system-level impacts of temperature-dependent transmission line models based on given ambient temperature profiles. In order to capture nonuniformity of line parameters caused by ambient temperatu...
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This paper discusses system-level impacts of temperature-dependent transmission line models based on given ambient temperature profiles. In order to capture nonuniformity of line parameters caused by ambient temperature gradients, a line model characterized by multiple nonuniform segments is used. An automated tool has been developed to obtain appropriate system models, given a set of temperature measurements and their locations along each system branch. Using these models, the impacts of temperature variations are investigated with respect to line terminal behavior (bus voltage) and maximum power transfer characteristics. Results for the IEEE 30-bus test system are presented.
A comparison is made between the mixed lumped and distributed equivalent two-port networks for spherical modes, as derived by Thal, and the mixed lumped and distributed equivalent networks for certain classes of nonun...
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ISBN:
(纸本)9781479900916
A comparison is made between the mixed lumped and distributed equivalent two-port networks for spherical modes, as derived by Thal, and the mixed lumped and distributed equivalent networks for certain classes of nonuniform transmission lines, as derived by Kobayashi. The extended Kuroda transform is used to derive a model for dipolar (radial index of 2) spherical mode propagation consisting of a nonuniform (but dispersionless) transmission line, a single lumped inductor, and an ideal transformer. Four different two-port models for dipolar spherical mode propagation are then compared, including: (1) Thal's mixed lumped and distributed model;(2) a model containing a parabolic nonuniform dispersionless transmission line derived using the extended Kuroda transform;(3) a model containing a second-order binomial form nonuniform dispersionless transmission line also derived using the extended Kuroda transform;and (4) the dispersive nonuniform transmission line model originally given by Marcuvitz. Finally, some motivation for the study of equivalent models is presented.
In this paper, a mathematical analysis of the EMI(Electromagnetic Interference) for a 20kHz/10kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transient ...
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ISBN:
(纸本)9783037857106
In this paper, a mathematical analysis of the EMI(Electromagnetic Interference) for a 20kHz/10kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transient switching interference is proposed. Due to the high working frequency and the device-switching transitions, the conducted EMI caused by the charging circuit which includes the harmonics of grid frequency, working frequency and device-switching transition frequencies. Thus under certain working situations or loads parallel power supply, the interference may cause charging failure. To solve this problem, a high frequency transformer modeled with stray capacitances and an approximation of the device-switching transition is applied in the Pspice-based simulation model, and a mathematical analysis in frequency-domain is presented.
A comparison is made between the mixed lumped and distributed equivalent two-port networks for spherical modes, as derived by Thal, and the mixed lumped and distributed equivalent networks for certain classes of nonun...
详细信息
A comparison is made between the mixed lumped and distributed equivalent two-port networks for spherical modes, as derived by Thal, and the mixed lumped and distributed equivalent networks for certain classes of nonuniform transmission lines, as derived by Kobayashi. The extended Kuroda transform is used to derive a model for dipolar (radial index of 2) spherical mode propagation consisting of a nonuniform (but dispersionless) transmission line, a single lumped inductor, and an ideal transformer. Four different two-port models for dipolar spherical mode propagation are then compared, including: (1) Thal's mixed lumped and distributed model; (2) a model containing a parabolic nonuniform dispersionless transmission line derived using the extended Kuroda transform; (3) a model containing a second-order binomial form nonuniform dispersionless transmission line also derived using the extended Kuroda transform; and (4) the dispersive nonuniform transmission line model originally given by Marcuvitz. Finally, some motivation for the study of equivalent models is presented.
In this paper, we propose a systematic procedure for the accurate design of classical dual-mode filters in circular wave-guide technology. The design procedure is based on the previous synthesis of an intermediate dis...
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In this paper, we propose a systematic procedure for the accurate design of classical dual-mode filters in circular wave-guide technology. The design procedure is based on the previous synthesis of an intermediate distributed model, which links the standard lumped (or coupling matrix) elements circuit with the practical waveguide realization. We then show how the equivalent distributed model can be directly used to obtain the physical dimensions of these filter components (typically rectangular and cross-shaped irises, as well as tuning and coupling screws). The value of this paper lies in the fact that the proposed design strategy provides the final dimensions of these complex structures with unprecedented levels of accuracy and numerical efficiency, as it is shown through two dual-mode filter designs for narrowband applications, and measurements of a manufactured prototype.
In this article, a method to miniaturize the broadband rat-race couplers using microstrip nonuniform transmission lines (MNTLs) is presented. The proposed coupler features a compact size on a single circuit layer stru...
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In this article, a method to miniaturize the broadband rat-race couplers using microstrip nonuniform transmission lines (MNTLs) is presented. The proposed coupler features a compact size on a single circuit layer structure without reactive components and via-holes. The design formulas are developed using ABCD matrix and even-odd mode analysis. The theoretical analysis has been verified by measurement of the manufactured broadband MNTL rat-race coupler with center frequency of 1.35 GHz and 89% fractional bandwidth. The isolation, magnitude, imbalance and phase imbalance are less than -20 dB, 0.5 dB, and 4 degrees, respectively, within 0.75-1.95 GHz frequency bandwidth.
This paper presents the first known synthesis method for the design of nonuniform transmission lines (NUTLs) for ultra-wideband (UWB) pulse shaping, which can account for, and partially compensate for, the loss and di...
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This paper presents the first known synthesis method for the design of nonuniform transmission lines (NUTLs) for ultra-wideband (UWB) pulse shaping, which can account for, and partially compensate for, the loss and dispersion present in real transmission lines. Without this compensation, cumulatively increasing distortion occurs in UWB pulse trains generated using NUTLs. The synthesis method novelly combines techniques from both the microwave and digital design domains: first, the transfer function of the transmission line is modeled as a cascade of minimum-phase and all-pass networks in the Z-domain;next, this model is used in a modified layer-peeling algorithm that automatically partially corrects for line nonidealities. Two possible implementations are presented: one taking advantage of noncausal filtering and the other with filtering implemented in the frequency domain. The effectiveness of the method is confirmed with both simulations and measurements of an UWB pulse shaper, which generates the first known sequence of modified Hermite polynomial pulses with successful compensation for loss and dispersion in an NUTL up to 15 GHz. The presented example shows that the synthesis method reduced the error between NUTL models and measurements by an average of 55%.
This paper discusses a transmission-line modeling approach that incorporates available ambient temperature information. Several proposed line modeling techniques are studied and include distributed and lumped paramete...
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This paper discusses a transmission-line modeling approach that incorporates available ambient temperature information. Several proposed line modeling techniques are studied and include distributed and lumped parameter models. In order to capture the nonuniformity of line parameters caused by temperature gradients, a model with multiple nonuniform segments is also proposed. An automated tool has been developed to obtain appropriate line model segmentation and parameter values of each segment, given a set of temperature measurements and their locations along the line.
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