Week 7 State of charge estimation

2 answer :

Coulomb counting method for SOC estimation matlab model

1.coloumb counting method measures the charging/discharging current of battery and integrates their values over time to estimate SOC.

if

SOC(t)=state of charge at instant t.

SOC(t-1)=state of charge at instant (t-1).

i(t) is charging or discharging current. i(t) is positive when charging otherwise negative.

u(t)=nominal capacity which depends on cell temperature in Ah

dt= time step in hours

then

SOC(t)=SOC(t-1)+ ( i(t)/u(t) )* dt

2.here in matalb model battery pack current is divided by 3600 and integrated by discrete time integrator to get charge in ampear hour that battery is charging or discharging and divided by nominal capacity which is function of cell temperature .later this entire fraction is added to initial SOC to get present SOC.