Showing papers on "Supercapacitor published in 1988"

Series connection of supercapacitor modules for energy storage

Abstract: STATCOMs have been considered as a technology to stabilise the grid voltage dynamically. However, its capability of instantaneous active power circulation is limited by a small amount of stored energy in a conventional capacitor. Supercapacitors are a promising energy storage technology to enhance the performance of a STATCOM by giving it the ability to exchange bursts of power. In transmission and distribution (T & D) applications, supercapacitors have to be connected in series in order to withstand high voltage stress. This paper describes the tests that were carried out to evaluate how supercapacitor modules can be connected in series, and to get insight into the characteristics of series-connected modules. Dominant parameters were identified and a suitable model of a high voltage/power supercapacitor was developed. This model can aid the design of topologies and control strategies to enhance the dynamic performance of STATCOMs.

Aluminium collector electrodes formed by the plasma spraying method for electric double-layer capacitors

Abstract: Aluminium collector electrodes, formed by the plasma-spraying method, have been developed for high-performance electric double-layer capacitors. The capacitors consist of activated carbon-fiber (ACF) cloth for polarizable electrodes, conductive aluminium layers for collector electrodes, a separator, and an organic electrolytic solution. Aluminium electrode layers formed by the plasma-spraying method showed low-electric-resistance effective electrical contact to the activated carbon-fiber cloth, and electrochemical stability in the electrolytic solution, which resulted in high-performance capacitors with low inner resistance and high capacitance. >

High power pulse energy system concept

Abstract: : New advances in capacitor technology create exciting opportunities in size and weight reduction for high-power, pulse energy systems having a broad range of applications. Characteristics of a proposed high power pulse energy system, formed by combining a recently developed, high-energy density capacitor with various batteries, were investigated. Main advantages of the system thus far appear to be high power and pulse energy density and flexibility in energy outputs. Parametric relationships between most key design variables, such as average pulse power, system output voltages, load impedance, pulse width, pulse frequency, duty cycle and battery's voltage and current limits, were established. Projections of the system's weights in large scale applications suggested that the lithium/SO2 battery considered might be too heavy when high duty cycles were required. However, significant weight reductions could be foreseen with proper selection of the battery and further advances in the capacitor technology. Keywords: Lithium Sulfur Dioxide Battery, Pulse energy, Burst power, Capacitor, High energy density, Electrochemical capacitor, Ultracapacitor.

A method of characterizing high energy density capacitors for power conditioning systems

Abstract: An effort was made to develop methods for characterizing CDL (chemical double layer) capacitors in terms of percent energy transfer to a resistive load as well as energy density packaging capabilities. A novel soft charging method, in contrast to constant-voltage charging, was developed to increase the energy density by approximately 1600% of the CDL capacitors' rated value. This method consists of slowly increasing the terminal voltage to approximately four times its rated value, achieving energy densities on the order of 4.5 kJ/kg (with case) and 6.5 kJ/kg (without case) for a life of several days. The capacitor studied showed promise in DC storage applications where high energy densities are required for relatively long discharge times. >