Week 7 State of charge estimation
1.
Matlab testing for 3 test condition from hardness dashboard .
case 1:
selecting the test sequence via variant block which allow you to select which test needs to be simulated. The first variant was selected intially for simulation which can seen below.
we can observe that from plot that the vehicle is intially in the driveing state and charging was done 90%.After the charging mode it reach to the standby mode which can be seen from the BMS state plot. cell tempreture plot is seen that the batttery tempreture rise in driveing and charging. voltage of battery increased to 4.2 v while charging. The current graph shows the current value supplied to vehcile while driving.The SoC was observed to be decreased around 50% in driveing condition.Which increased while charging.
CASE 2:
It was observed that from the plot that battery discharge completly in 8692 sec and the vehicle does not go forwoard and charging state not achieved at 10000 seconds.Hence the vehicle comes to standby condition and simulation stop midway.
case 3:
we oberve in the plot that battery start charging and SoC starts increasing from beginning to around 2000 seconds and stay stable at 100% continuosly from 20000seconds.The peak current plot from 0 to 2000 seconds and stay as constant as the charge is not used anywhere as the driving is not present.
2.
Coulomb counting is a method used for measure battery discharge current andintergrate the dischargeing current over time order to estimate SoC.Couloumb counting method is done to estimate the SoC,which is estimated from the dischargeing current,IT and previously estimated SoC value SoC(t-1).SoC is calculated by following equation:
then move to BMS ECU
then move to SoC estimation
As you can see coulomb cuting model is at the top of the model.In the block coulomb couting has been carried out.
As you can observe that only tempreture and current taken as input .current is connected to the gain block and tempreture is connected to the capacity as it varies.then both of the input moves to arithmatic operation block then its out has to be intergrate with respect to the time .The output after integration given to SoC block for futher counting the SoC level.