State estimation SOC and SOH for BMS

Hello MATHwork,

I am doing develop algorithms for the BMS and I am facing problem to develop algorithms for state estimation (SOC and SOH). In my project, 10 cells batteries will use (3.67 V, 95AH) and total capactiy 36.7 V, 3.5 Kwh. I am using adaptive extended kalman filter for SOC measurement (Simscape battery) and SOH (Simscape battery).

My problem is that when I run the model and check it my graph for SOC and SOH so it will totallly incorrect it. I don't know how to solve this problem and correct the value for SOC and SOH and develop correct algorithms. Please if you have example so you can send it me. I have also check MATHWORK example, documentation and also surfing community options but I didn't find solution for it.

Thank you !

Kind regards,

Jigarkumar lukhi

Answer 1

[Sayan]

Hi @Jigarkumar,

I understand that you are facing issues while running your algorithm to estimate SOC and SOH for your BMS. Some possible reasons for the error are mentioned below.

• If you are using the Simscape battery (available at Simscape/Electrical/Sources) model it needs to be ensured that the model follows the specific chemistry, like voltage dynamics,temparature effect and charging dynamics of the battery for which BMS needs to be implemented.
• A low-pass filter can be added to reduce the noise at voltage and current measurements.
• Ensure the initial values of SOC and SOH are close to the actual values.

Further, the blocks SOC Estimator and SOH Estimator available at Simscape/Battery/BMS/Estimators can be used directly in Simulink. The following documentation can be followed:

https://www.mathworks.com/help/releases/R2022b/simscape-battery/ref/socestimatorkalmanfilter.html

https://www.mathworks.com/help/releases/R2022b/simscape-battery/ref/sohestimator.html

Some examples of SOC and SOH estimation models can be found here.

https://www.mathworks.com/help/releases/R2022b/simscape-battery/ug/battery-state-of-health-estimation.html

https://www.mathworks.com/help/releases/R2022b/simscape-battery/ug/battery-state-of-charge-estimation.html

Hope this helps resolve the issue.