How to create a 2-RC circuit in SOC Estimator (UKF) block?

Hi, I want to change the SOC Estimator (UKF) block in Simulink with a 2-RC circuit instead of a 1-RC circuit. For this is use the simscape battery toolbox.

The states would be x = [SOC, V1, V2, R0], and the output is y = Vocv - V1 - V2 - R0*I.

I have tried to update the state function (see picture below) and measurement function, but I keep receiving errors that my input values don't match up. This is understandable, as I am trying to change the number of inputs from 3 to 4, but I don't know how to resolve this problem.

I really appreciate any tips that you might have to solve this issue. Thank you.

Answer 1

[Sanchari]

Hello Lotte,

I understand that you want to change the SOC Estimator (Adaptive Kalman Filter) block in Simulink to a 2-RC circuit instead of a 1-RC circuit. However, this is not possible using the SOC Estimator (Adaptive Kalman Filter) block as it is modelled to work with a 1-RC circuit.

You can try other methods to calculate SOC by referring to the following documentation:

• Simulink Example: Please try the Simulink example for “Battery State-Of-Charge Estimation”. Type the command >> openExample('simscapebattery/BatterySOCEstimationExample'), to open the example. Source link: https://www.mathworks.com/help/simscape-battery/ug/battery-state-of-charge-estimation.html
• SOC calculation using Coulomb Counting method:
• a. https://www.mathworks.com/support/search.html/answers/1830483-how-to-use-soc-estimator-coulomb-counting.html?fq%5B%5D=asset_type_name:answer&fq%5B%5D=category:simscape-battery/estimators&page=1
• b. https://www.mathworks.com/matlabcentral/answers/649578-coulomb-counting-calculation-of-the-battery-soc?s_tid=srchtitle
• SOC calculation using Voltage method:
• a. https://www.mathworks.com/support/search.html/answers/1876232-battery-soc-using-voltage-method.html?fq%5B%5D=asset_type_name:answer&fq%5B%5D=category:support/propulsio6651&page=1
• b. https://www.mathworks.com/help/autoblks/ref/battery.parameters.lookupsocfromvoltage.html?searchHighlight=SOC%20voltage&s_tid=srchtitle_support_results_1_SOC%20voltage

You can further refer the following documentation and File Exchange function:

1. SOC Estimator (Adaptive Kalman Filter): https://www.mathworks.com/help/simscape-battery/ref/socestimatoradaptivekalmanfilter.html?searchHighlight=SOC%20voltage&s_tid=srchtitle_support_results_9_SOC%20voltage
2. State of Charge Estimation Function based on Kalman Filter: https://www.mathworks.com/matlabcentral/fileexchange/90381-state-of-charge-estimation-function-based-on-kalman-filter?s_tid=answers_rc2-2_p5_MLT

Hope this helps!