基于DSP的电动汽车蓄电池电量计量及荷电状态估计

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

荷电状态是反映蓄电池能量的重要参数,是电动汽车整车控制器制定能量控制策略的重要依据。为了解决电动汽车蓄电池电量计量及荷电状态估计问题,设计了基于数字信号处理器(DSP)的蓄电池电量快速计量系统,采用安时法对蓄电池充放电容量进行了估计,通过放电率、温度、自放电及容量老化等补偿措施来提高计量精度,并分析了温度与充放电倍率对蓄电池容量的影响。试验结果表明,补偿后的安时法可准确地估计蓄电池荷电状态,最大充放电倍率随温度升高而增大。

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.