Electricity quantity measurement and SOC estimation of storage battery in electric vehicle based on DSP

ZUO Shi-gou1， ZHOU Ya1，2， ZHANG Da3
（1. Shanghai Communications Polytechnic， Shanghai 200431， China；
2. Shanghai Communications School， Shanghai 200431， China；
                3. School of Electronics and Information， Tongji University， Shanghai 201804， China）

Abstract： State of charge （SOC） is a critical parameter which reflects the energy state of storage battery. SOC is an important basis of energy control strategy in electric vehicle controller. In order to solve the problem of electricity quantity measurement and SOC estimation of storage battery in electric vehicle， a rapid electric energy measuring system based on digital signal processor （DSP） was designed. Ampere-hour method was adopted to estimate the charge and discharge capacity of storage battery. Compensation measures such as discharge rate， temperature， self-discharge and capacity ageing were used to improve the precision of computation. Meanwhile， influences of temperature and charge-discharge rate on battery capacity were analyzed. Experiments results show that SOC can be accurately estimated by compensated Ampere-hour method and the maximum charge-discharge rate increased with the temperature increment.
Key words： electric vehicles； storage battery； state of charge（SOC）； digital signal processor （DSP）