Measurement of Lithium Ion Capacitor Block Characteristics of Voltage Equalization Method and DC UPS Embedded Design

Abstract

The characteristics of Lithium Ion Capacitor (below , abbreviated as LIC) as a charging device is similar to Lithium Ion Battery and has quite long life, it is 100 times more than Lithium Ion Battery charge and discharge cycles. But it has one tenth of capacity of Lithium Ion Battery. For that reason, increasing the energy availability is important for LIC system. In this paper, in order to increase efficiency of discharge, effectiveness of voltage equalization method of LIC was checked and correctness of firmware design, circuit design and PCB design as an embedded system was confirmed. The method is in a sense simple that is repeatedly switching the parallel connection of the capacitors and serial connection of them. The reputation cycle of this system is 1 kHz to 50 kHz for experimental purpose. The implement of this method for seven to eight LICs is shown in this paper. This system is implemented as a DC output UPS. Because the LIC block is easy to generate switching noise and switching loss, it is difficult to measure the characteristics and property other than realizing UPS unit as an embedded system including software and hardware (mainly circuit and PCB) design. In this embedded system, The Cypress PSOC microcontroller is adopted to get flexibility and to control many Power MOS FETs for switches and the circuit is implemented by four layer PCB.