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Negative impedance converter

About: Negative impedance converter is a research topic. Over the lifetime, 5801 publications have been published within this topic receiving 87636 citations.


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Patent
20 Mar 1995
TL;DR: In this article, a weighted discrete fourier transform is applied to the digitized current and voltage waveforms of a motor to obtain negative sequence voltage and current phasors, which are then used to determine the existence of a turn fault.
Abstract: Motor current and voltage waveforms are measured and converted to digitized current and voltage waveforms. A weighted discrete fourier transform is applied to the digitized current and voltage waveforms to obtain negative sequence current and voltage phasors; and the negative sequence current and voltage phasors are used to determine the existence of a turn fault. The use of the negative sequence current and voltage phasors can be performed by employing one of several techniques. In a first embodiment, an apparent negative sequence impedance is estimated by dividing the negative sequence voltage phasor by the negative sequence current phasor for comparison with a threshold negative sequence impedance. In a second, related embodiment, a current differential is estimated by dividing the negative sequence voltage phasor by a characteristic negative sequence impedance and subtracting the result from the negative sequence current phasor for comparison with a threshold current differential. In a third, related embodiment, a voltage differential is estimated by multiplying the negative sequence current phasor by a characteristic negative sequence impedance and subtracting the result from the negative sequence voltage phasor for comparison with a threshold voltage differential. In either of the second or third embodiments, the characteristic negative sequence impedance can be obtained by inserting a calibration device into one phase of the motor.

55 citations

Journal ArticleDOI
TL;DR: State-of-the-art InAs/InGaAsSb/GaSb nanowire TFETs are employed as the baseline transistor and PZT and silicon-doped HfO2 as ferroelectric materials.
Abstract: Nanowire tunnel field-effect transistors (TFETs) have been proposed as the most advanced one-dimensional (1D) devices that break the thermionic 60 mV/decade of the subthreshold swing (SS) of metal oxide semiconductor field-effect transistors (MOSFETs) by using quantum mechanical band-to-band tunneling and excellent electrostatic control. Meanwhile, negative capacitance (NC) of ferroelectrics has been proposed as a promising performance booster of MOSFETs to bypass the aforementioned fundamental limit by exploiting the differential amplification of the gate voltage under certain conditions. We combine these two principles into a single structure, a negative capacitance heterostructure TFET, and experimentally demonstrate a double beneficial effect: (i) a super-steep SS value down to 10 mV/decade and an extended low slope region that is due to the NC effect and, (ii) a remarkable off-current reduction that is experimentally observed and explained for the first time by the effect of the ferroelectric dipoles, which set the surface potential in a slightly negative value and further blocks the source tunneling current in the off-state. State-of-the-art InAs/InGaAsSb/GaSb nanowire TFETs are employed as the baseline transistor and PZT and silicon-doped HfO2 as ferroelectric materials.

55 citations

Patent
30 Jul 2009
TL;DR: In this article, a DC/DC voltage converter includes an inductive switching voltage regulator and a capacitive charge pump connected in series between the input and output terminals of the converter, which reduces the series resistance in the current path by which charge is transferred from the capacitor in the charge pump to the output capacitor.
Abstract: A DC/DC voltage converter includes an inductive switching voltage regulator and a capacitive charge pump connected in series between the input and output terminals of the converter. The charge pump has a second input terminal connected to the input terminal of the converter. This reduces the series resistance in the current path by which charge is transferred from the capacitor in the charge pump to the output capacitor and thereby improves the ability of the converter to respond to rapid changes in current required by the load.

55 citations

Journal ArticleDOI
Juan Bisquert1
TL;DR: The basic recombination-modulation model is formulated in terms of an equivalent circuit for small ac perturbation and the application of the results in measurements of impedance spectroscopy of dye-sensitized solar cells, organic solar cells and related systems is discussed.
Abstract: A simple model for conductivity modulation in a recombination diode is discussed to explain the observation of negative capacitance at forward bias observed in many optoelectronic devices. We formulate the basic recombination-modulation model in terms of an equivalent circuit for small ac perturbation and discuss the application of the results in measurements of impedance spectroscopy of dye-sensitized solar cells, organic solar cells and related systems.

55 citations

Journal ArticleDOI
TL;DR: The negative impedance converter (NIC) as discussed by the authors is a simple analog building block which can be readily implemented in CMOS and provides precise temperature-compensated linear operation for single-pin crystal oscillators, zero-impedance current sensing and wideband integration.
Abstract: The authors describe the negative impedance converter, a simple analog building block which can be readily implemented in CMOS. They present a circuit based on the inverse-function approach, providing precise temperature-compensated linear operation. Applications include single-pin crystal oscillators, zero-impedance current sensing, and wideband integration. Simulated and measured characteristics are in good agreement, and show that useful negative resistance can be obtained to over 10 MHz. >

55 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202330
2022104
2021120
2020131
2019134
2018155