Topic
Output impedance
About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.
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30 Oct 1988
TL;DR: In this article, the characteristics of a cell's impedance may lead to improved accuracy or suggest measurement techniques best suited for evaluating capacity by impedance measurements, and some measurements made in an effort to achieve this objective.
Abstract: The author suggests that more understanding of the characteristics of a cell's impedance may lead to improved accuracy or suggest measurement techniques best suited for evaluating capacity by impedance measurements. He describes some measurements made in an effort to achieve this objective. The cell chosen for this work was a Globe model TCG-1680, a flooded lead-calcium cell sized at 1680 A hours at the 8 h rate. Comparisons between lumped constant networks and cell impedances are discussed as well as linearity and surface charge effect. >
109 citations
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17 Mar 2013TL;DR: In this article, the influence of the phase-locked loop (PLL) on the input admittance of three-phase Voltage-Source Converters (VSC) for open loop, current-feedback and voltage feedback control conditions is analyzed.
Abstract: A regulated power converter can cause instability issues at its terminals with its input filter or the source. The Generalized Nyquist stability Criterion (GNC), when applied to the product of the source impedance and load admittance in the dq frame, can be used to analyze the stability of balanced three-phase ac systems. This paper presents the influence of the Phase-Locked Loop (PLL) on the input admittance of three-phase Voltage-Source Converters (VSC) for open loop, current-feedback and voltage feedback control conditions. Analytical results show that the PLL introduces a parallel admittance to the open loop admittance of the VSC, and that the current and voltage control loop have additional effects on it. Both simulation and experimental results are presented to verify this analysis. The possible instability due to different PLL design is also shown.
108 citations
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TL;DR: Comparisons have shown that, besides higher accuracy and output resistance, the proposed circuit has no residual error, but has a wider output voltage swing, a much higher PSRR, and an easier and more flexible design.
Abstract: An accurate, very-high-output-resistance active-feedback cascode current mirror has been proposed and compared with a previously reported accurate cascode current mirror. Comparisons have shown that, besides higher accuracy and output resistance, the proposed circuit has no residual error, but has a wider output voltage swing, a much higher PSRR, and an easier and more flexible design.
108 citations
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03 Nov 1976TL;DR: In this article, an impedance level detector is used to detect the impedance between the outputs of the pacemaker's output and the power source's output to provide a warning signal indicating that the output impedance falls outside a predetermined range.
Abstract: Apparatus for stimulating body tissue and in particular the heart, is disclosed as including a device or circuit responsive to the initiation of stimulation and/or to the failure or pending failure of a component of the stimulating apparatus to provide the patient with a perceivable stimulation to a second, different portion of body tissue. There is disclosed an impedance level detector for sensing the impedance presented between the outputs of the stimulation apparatus to provide a warning signal indicating that the output impedance falls outside a predetermined range. In particular, the impedance level detector output is sensed by a stimulation control logic to apply a first train of pulses at a first rate to an auxiliary electrode for stimulating the second portion of tissue. Further, there is included a voltage level detector for sensing when the power source voltage depletes below a predetermined level, to actuate the stimulation control logic to provide a second train of warning pulses to the auxiliary electrode, at a second, different rate than that of the first train. In this fashion, the patient not only is warned as to the pending failure or failure of a component of his pacemaker, but also is able to identify the failing component.
108 citations
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TL;DR: In this paper, a method for modeling small-signal input impedance of line-frequency AC-DC converters is presented, which can be used for stability analysis of AC power systems with significant DC loads powered by such converters.
Abstract: This paper presents a systematic method for modeling small-signal input impedance of line-frequency AC-DC converters. The objective is to develop proper models that can be used for stability analysis of AC power systems with significant DC loads powered by such converters. The proposed modeling method uses harmonic linearization and Fourier analysis techniques to describe the current and voltage mapping process through the converter switching circuit. The voltage and current mapping relations are then combined to give an impedance mapping model which converts the impedance of any circuit or system connected to the DC output of converter into a corresponding small-signal input impedance of the converter at the AC side. Similar relations can be used to map the AC source impedance into the DC side to give the equivalent dc source impedance for stability analysis of the DC subsystem. This paper focuses on the basic principle of the impedance mapping method and uses a single-phase diode rectifier circuit to demonstrate the modeling process. The resulting ac input impedance model is validated by detailed circuit simulation as well as experimental measurements.
108 citations