Week 7 State of charge estimation
Objectives:
1.Simulate the 3 test cases from harness dashboard and write a detailed report on the results
2.What is coulomb counting? Refer to the above model and explain how BMS implements coulomb counting for SOC estimation ?
Above Objectives from given MATLAB Simulink file.
1)Answer:
Select the harness dashboard file from given link that is mentioned in the question and after click on select sequency blolck and double click o it.
Choose the first test case from that we conclude that upto 3000 seconds battery in driving mode ,upto4000 seconds Balancing mode ,4000 to 5000 seconds charging and balancing mode and after 5000 seconds battery in past charge balancing mode.
From below diagram we conclude that no fault is there because all lights have turned green.
1st Case Results:
From below temperature plot we can say the temperature increasing in driving and charging mode.in the driving mode the current is suppling that will be observed from current plot,4.2v is final voltage of the cell
observed from voltage plot and 50% soc when it in driving mode.
Now select the 2nd test sequence variant condition:
The Condition for the second test sequence variant is driving mode is from 0 to 10000 seconds, after 10000 seconds which is in charging mode.
Results 2nd test sequence variant condition:
From below plots we conclude that the discharging is happens approximatlay upto 9000 secondns and the voltage does not go frowarad beacuase it is reaches minimum value of cell voltage so the BMS does not allow to draw current upto 10000 seconds.from curent plot we can say the current varries from -70 to20 A, SOC at intialy is 80%.
Now select the 3rd test sequence variant condition:
From 3rd sequence variant condition we can say that from 0 to 20000 seconds only charging means only one mode that is charging mode.
Results 3rd test sequence variant condition:
0 to 20000 seconds only one mode that charging mode and here the battery SOC is 100% from test varients we understand beavaiour of battery on driving mode ,charging mode and balancing mode.
coulomb counting: it is a technique used to track the state of charge of a battery . It works by integrating the active flowing current (measured in amps) over time to derive the total sum of energy entering or leaving the battery pack. This produces a capacity that is typically measured in Ah.
SOC is can estimate using Discharge current and previous value of state of charge with respect time.
MATALB simulation model coulomb counting:
the coulmob counting methode technique measure the discharging current of cell and intigrates the current over time to estimate SOC.