The Research Of Supercapacitor Voltage Management System Based On FPGA

Supercapacitor has the features of high power density, low resistance, wide temperature range, and suitability for quick charge and discharge. So the energy storage system based on supercapacitor is very suitable applied in hybrid electric vehicle(HEV). In actual applications, because the single supercapacitor’s voltage is not high, dozens or even hundreds of supercapacitors need to be connected in series to achieve the required voltage. Normally, the performance of each supercapacitor in series is inconsistent, it will be increased voltage difference between supercapacitors after a number of deep discharging/charging cycles, and this will accelerate the aging of supercapacitors. So a management system with equalization function is essential when supercapacitor stacks are used in actual applications as energy storage system.In this paper, a practical supercapacitor voltage management system is proposed, which is consisted by FPGA module, AD conversion module, switch module, voltage conversion module and VGA display module. In the system, FPGA is the control core. It’s working mechanism as follows: The voltage signal of each supercapacitor is collected by monitoring system and further sent to FPGA through AD conversion module. The signal will be processed by FPGA and two-way equalization strategies are carried out at the same time by driving the switch module. In this system, VGA display module is used to display the voltage of each supercapacitor in the form of images, so the working condition of each supercapacitor can be displayed very clearly.The experimental data are analyzed. Because the two-way equalization strategy are carried out at the same time, so it has a high balance speed and good effect.As a result, energy will be transferred from the higher ones to the weaker ones, which can effectively achieve dynamic balance of supercapacitors’ voltage. The system can avoid the supercapacitors in the stacks being overcharged or over-discharged in both charge and discharge process.