ULTRACAPACITOR BASED STORAGE SYSTEM （基于电容的存储系统）.pdf

ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 25.-27.05.2016. ULTRACAPACITOR BASED STORAGE SYSTEM FOR LEAD-ACID POWERED LIGHT ELECTRIC VEHICLE RETROFIT Kaspars Kroics, Viesturs Brazis Riga Technical University, Latvia Kaspars.Kroics@, viesturs.brazis@rtu.lv Abstract. The paper presents the concept of a supercapacitor based plug-in retrofit kit that can be easily installed on the electric vehicle powered by lead-acid batteries without the intervention in the control system to store regenerative braking energy, improve battery lifetime and efficiency. The installation of the retrofit can be done in a simple manner by connecting of only two wires to the DC bus and by installing a contactless current sensor on the battery wire. Many control strategies can be implemented to control such system. The paper is focused on the efficiency optimization. This purpose is achieved through regulation of supercapacitor based energy storage current proportionally to the battery current in the discharge process. Theoretical equations, Matlab simulation results and experimental results on the test bench are presented in the paper and show the validity of the approach. Keywords: low speed electric vehicles, lead-acid batteries, supercapacitors. Introduction The fossil fuel resources in the world are consumed at a very fast rate and could be emptied in near future. Increasing of transportation efficiency is the best place to start efforts to reduce internal combustion engines emissions. Light electric vehicles (LEV) are the only commercially available alternative to the conventional internal combustion engine cars, which in terms