Battery/Supercapacitors Combination in Uninterruptible Power Supply (UPS)

International audienceThis study presents a study of the reduction in battery stresses by using supercapacitors (SCs) in a 500-kVA rated UPS. We aim at investigating the optimal supercapacitors-battery combination versus the SCs cost. This investigation is threefold; first, supercapacitors and battery models developed using MATLAB/Simulink are presented and validated. Second, the architecture and the simulation of the designed system that combines the SCs and the battery are shown. The supercapacitors are used as high-power storage devices to smooth the peak power applied to the battery during backup time and to deliver full power during short grid outages. By charging the SCs through the battery at a suitable rate, all impulse power demands would be satisfied by the supercapacitors. Third, extensive simulations are carried out to determine the gain in battery RMS current, the gain in energy losses, the energy efficiency and the elimination rate of surge load power. These four performance parameters are determined by simulation and then analyzed. The influence of the SCs recharge on the performance indicators is highlighted. A thorough analysis involving optimal study proposes to draw the optimal SCs number and filter constant from the variation of the aforementioned parameters versus the cost of the SCs

Design of power sharing system between supercapacitors and battery in an uninterruptible power supply

International audienceIn this paper we present a strategy to combine supercapacitors with the battery in a 500 kVA rated uninterruptible power supply. First the sizing of the supercapacitors and battery taking into account the UPS specifications is presented. The validation of the supercapacitor and the battery models is carried by using MATLAB/SIMULINK. Second, the power sharing system between the supercapacitors and the battery is presented. The supercapacitors are added as higher energy storage to overcome the full load power during short time grid failures and to boost peak power during backup time of few minutes. The UPS waveforms obtained by simulation are presented and analyzed

Utilization of supercapacitors to reduce lead acid battery stresses in UPS

ISBN: 978-1-4673-1168-7International audienceThis work presents the study of the reduction in battery stresses by using supercapacitors (SC's) in a 500 kVA rated UPS. We aim at investigating the optimal SC-battery combination versus the SC's cost. This investigation is threefold; first, supercapacitors and battery models developed using Matlab/Simulink® are presented and validated. Second, the architecture and the simulation of the designed system combining the two types of storage devices are shown. The study emphasizes on UPS autonomous running for grid faults lasting few minutes, the supercapacitors supply the transient demand of power and the battery is responsible for the smoothness requirement of energy. Third, extensive simulations are carried out to determine the gain in battery RMS current, the gain in energy losses, the energy efficiency and the elimination rate of surge load power. These four performance parameters are determined by simulation and then analyzed. They reflect the potential decrease in battery stresses due to the SC's. A thorough analysis involving optimal study proposes to draw the optimal SC's number and filter constant from the variation of the aforementioned parameters versus the cost of the SC's

Control Strategy for Optimal Combination of Supercapacitors and Battery in 500 kVA rated UPS

Accès à l'article complet (Open Access) : http://www.waset.org/journals/ijeee/v6/v6-16.pdfInternational audienceIn this paper we present an optimal method that combines supercapacitors with the battery in a 500 kVA rated uninterruptible power supply (UPS). Supercapacitors are used as high power storage devices to smooth the peak power applied to the battery during backup-time and to deliver full power during short grid outages. First, supercapacitors and battery models are developed then validated using Matlab/Simulink®. Second, the architecture and the simulation of the designed system combining the two types of storage devices are shown. Finally, extensive simulations are carried out to determine the gain in battery RMS current, the gain in energy losses, the energy efficiency of the global system and the elimination rate of peak power applied to the battery through the battery at a suitable rate, all impulse power demands would be satisfied by the supercapacitors. The influence of the SC's on the performance indicators is analyzed. Optimal combination of two storage devices is obtained taking into account the supercapacitors cost