Week 7 State of charge estimation

1.   HARNESS DASHBOARD:

• WE HAVE TO SIMULATE THE 3 TEST CASES FROM HARNESS DASHBOARD.

TEST CASE 1:

•     WHEN WE CLICK ON THE SEQUENCE VARIANT BLOCK AND SELECT CASE 1.
• CLICKING ON THE BMS SEQUENCE BLOCK WE GET THE CHART.
• WHEN THE SIMULATION WILL START THE MODEL IS IN DRIVING COBNDITION.
• AFTER THE 3000 SECONDS IT WILL BE IN STANDBY MODE AND AFTER 100 SECONDS IT WILL BE IN CHARGIG MODE.
• WHEN WE RUN THE SIMULATION, ALL INDICATORS ARE IN GREEN .
•  THEREFORE WE CAN CONCLUDE THAT NO ERRORSS AND ALSO WE CAN SEE THE PLOT ITSELF

RESULT;

•  FROM THE GRAPH WE CAN SAY THAT VEHI CLE IS INTIALLY IN DRIVING STATE AND CHARGING WAS DONE TILL 90%.
•  AFTER CHARGING IT GOES TO STANDBY MODE CAN BE SEEN  IN BMS PLOT.
• TEMPERATURE OF BATTERY INCREASES IN DRIVING AND CHARGING AND VOLTAGE WAS INCREASED WHILE CHARGING.
•  CURRENT PLOT SHOWS HOW MICH CURRENT SUPPLIED TO THE VEHICLE WHILE DRIVING.
•  SOC DECREASED UPTO 50% IN DRIVING AND INCREASED IN CHARGING .

 

TEST CASE2:

• AFTER CLICKING ON THE SEQUENCE VARIANT AND SELECT CASE 2.
•  AND CLICKING ON BMS  SEQUENCE WE GET CHART.
• DRIVING STATE IS O TO 10000 SECONDS.
•  AND THEN CHARGING STAGE OCCURS.

 

RESULT:

 A FAULT CONDITION IS OCCURED IN THIS CASE, EVEN AFTER CHARGING WAS STARTED SOC IS NOT INCREASED IT CONTINUES TO DECREASE.

 

TESTCASE3:

AFTER CHANGING IN THE SEQUENCE VARIANT TO TEST CASE 3 AND GETTING INTO THE BMS WE GET CHART.

IT HAS ONLY ONE PHASE CONDITION , IT IS CHARGING FROM 0 TO 20000 SECONDS SIMULATION RUNS.

RESULT:

      WE CAN OBSERVE THAT SOC REACHED 100% IN CHARGING AND REMAINED IN STANDBY MODE.

 CELL TEMPERATURE ALSO DECREASED WHEN STANDBY MODE IS ACHEIVED.

 

                   FROM THE 3 CASES WE OBSERVE THAT ONLY CHARGING TAKES PLACE SO SOC WAS AT 80% FIRST THEN INCREASES TO 100% IN 2000 SECONDS AND REMAINS CONSTANT AT 100%

 

 

 

 

 

 

2. COULOMB COUNTING:         

•  IT MEASURES THE DISCHARGING CURRENT OF A BATTERY AND INTEGRATES THE DISCHARGING CURRENT OVERTIME IN OREDER TO ESTIMATE SOC.
•  COULOMB COUNTING METHOD IS DONE TO ESTIMATE FROM DISCHARGING CURRENT AND PREVIOUS ESTIMATED SOC VALUES AND IS CALCULATED BY A EQUATION.
• AND ANEW TECHINIQUE CALLED MODIFIED ONE IS PROPOSED, IT USES THE CORRECTED CURRENT  TO IMPROVE ACCURACY OF ESTIMATION.
• IT IS FUNCTION OF DISCHARGING CURRENT OF BATTERY IS IN THE FORM OF QUADRATIC EQUATION.
• SEVERAL FACTORS AFFECT THE THIS METHOD SUCH AS TEMPERATURE,BATTERY HISTORY, DISCHARGE CURRENT, CYCLE LIFE. 

WHEN WE TAKE AN EXAMPLE MODEL OF BMS SUCH AS OPEN LOOPED SYSTEM, BY OBSERVING THE MODEL WE CAN CONCLUDE SOME POINTS SUCH AS:

• ON OPENING THE ESTIMATION BLOCK WE GET THE AND OBSERVE THE COULOMB COUNTING METHOD.
• ON COULOMB COUNTING BLOCK HAS A SUBSYSTEM AND THIS SYSYTEM DOES THE ESTIMATION OF COUNTING EQUATION.
•  ITS ADVANTAGE IS SIMPLICITY AND LOW COST.
• TEMPERATURE AND CURRENT IS GIVEN AS INPUTS.
• CURRENT SIGNAL IS GIVEN TO THE GAIN BLOCK AND TEMPERATURE TO CAPACITY AND VARIES FROM TEPERATURE.
•  THIS INPUTS ARE GIVEN FOR INTEGRATION WHERE CURRENT WILL BE INTEGRATED.
• AND OUTPUT IS GIVEN TO ANOTHER BLOCK ANDD IT IS DIVIDE BY CAPACITY.
• SO WE CAN ESTIMATE THE SOC.