Capacitor

Este libro brinda una introducción a la electrónica en semiconductores -también llamada de estado
sólido- para carreras de ingeniería en electrónica, electricidad, computadoras, comunicaciones, control y sistemas. Provee una explicación de los mecanismos de conducción eléctrica en Silicio,
que luego se utiliza para el desarrollo de cuatro dispositivos fundamentales de la electrónica actual: el diodo de juntura, el capacitor Metal-Oxido-Semiconductor (MOS), el transistor MOS, y el transistor bipolar de juntura. El libro conduce al estudiante a que entienda el funcionamiento de cada dispositivo, partiendo de sus principios fundamentales, y que a partir de allí, comprenda en profundidad los diferentes modelos eléctricos que puede utilizar para representarlo, sus alcances y limitaciones. El objetivo último es que el estudiante conozca y sepa utilizar los distintos modelos de los dispositivos electrónicos, de acuerdo al rango de amplitud y frecuencia, para su utilización futura en el diseño y análisis de circuitos.

The dielectric constants (relative permittivities) of water, methanol, ethanol, butanol and acetone were measured at 91.3 kPa and (283.15 and 293.15) K and are reported here. The dielectric constants were determined by using a new setup based on a low-pass filter. The obtained dielectric constant values are compared with those reported in the literature, and are consistent with those reported in the literature. The obtained dielectric constant data were also compared with those calculated by the Kirkwood model. The comparisons indicated that Kirkwood model can be successfully used for calculation of dielectric constants of the pure fluids.

It is well-known that the high-performance polymeric dielectric films used for high-voltage DC capacitors should have outstanding capabilities in terms of electrical and mechanical properties in order to face harsh operating conditions. Many factors limit the ability of these thin films to face different and growing stresses according to modern electrical requirements. Microstructure properties, additives, impurities, defects formed during manufacturing as well as applied stress types significantly affect the performance of dielectric films and their operational lifetime. This paper presents a comprehensive review of the factors which affect the ageing, degradation and breakdown of metallised polypropylene (PP) capacitors films. The effects of microstructure, surface morphological properties, mechanical properties and defects on the reliability of biaxially oriented polypropylene films (BOPP) are studied. In addition, the phenomena affecting dielectric performance and ageing mechanisms which are induced by electrical, thermal and electrothermal stresses are discussed.

In this article, double-stacked and triple-stacked metal-insulator-metal (MIM) capacitors fabricated in 0.18 μm CMOS process are reported. These provide high-capacitance density of 2 fF/μm2 and 3.2 fF/μm2 and excellent dc and RF characteristics, respectively. The lumped circuit model of the stacked MIM capacitors is presented for high-frequency applications up to 20 GHz. The stacked MIM capacitors offer a reduced chip area for a given capacitance value and are expected to be a viable choice for integration of RF/mixed-mode circuits in a single chip. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1235–1238, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24305

This paper proposes a control strategy of open winding permanent magnet synchronous motor (OW PMSM) in field weakening modes. There are two inverters. One of them connected to the traction battery. Main bridge inverter aimed to provide power with approximately unity power factor, another one to capacitor. Floating bridge inverter aimed to control capacitor voltage on desired value and provide reactive power to the moto. Compare OW PMSM control system with conventional field-oriented control (FOC) shows that proposed method helps to reach speed 1.41 times more than FOC system. FOC system was simulated with 310V DC power supply. OW PMSM with 160V DC power supply and 500 nanofarad capacitor.

This paper investigates voltage and reactive power control in radial and closed loop distribution systems and how the presence of distributed generation (DG) affects the control. Comparative analysis between voltage and reactive power control in radial and closed ...

Today, ultracapacitors are a viable component for production aim designs in the power electronics world. The need for highly reliable back-up and emergency power are creating significant markets for energy storage and power delivery. Electrical wind turbine pitch systems, uninterruptible power supplies and electronic products such as wireless communication devices and digital cameras are some of the many applications where ultracapacitors have been designed in. Ultracapacitors are components which have properties of a complexe capacitor system which is sensitive to voltage, temperature and frequency. The understanding of their behavior is primordial to characterize and operate them.

In compact pulsed power conditioning systems, a high electric energy density of its capacitors is of interest. Commercially available capacitors are normally designed for long storage time and long lifetime. The performance of capacitors in terms of energy density capability can be improved by overstress or overcharge, that is, charging to a significantly higher energy density than specified. This paper explores the limits of overstressing commercially available capacitors for short time spans. The selected capacitors have a nominal dc voltage in the range of 2.5-10 kV and a capacitance in the range of 0.015-0.12 /spl mu/F. Two different storage times have been considered: 2 /spl mu/s and 20 ms. A high-voltage test setup was constructed. For the short storage time, it was possible to overstress the energy density as compared to nominal values with a factor of 26 and for the long storage time with a factor of 14 for the best performing capacitor. Other capacitors behaved significantly poorer, especially for the long storage time.

A new architecture for improvement of slew rate (SR) of an op-amp or an operational transconductance amplifier (OTA) in FinFET technology is proposed. The principle of operation of the proposed architecture is based on a set of additional current sources which are switched on, only when OTA should provide a high current, usually for charge or discharge of large load capacitor. Therefore, the power overhead is less compared to conventional high SR designs. The commonly used two-stage Miller-compensated op-amp, designed and optimized in sub 45 nm FinFET technology with 1 V single supply voltage, is used as an example for demonstration of the proposed method. For the same FinFET technology and with optimal design, it is shown that the slew rate of the op-amp is significantly improved. The slew rate is improved from 273 to 5590V/μs for an input signal with a rise time of 100 ps. The other performance measures such as gain and phase margin remain unchanged with the additional circuitry u...