Need information why charge and discharge are different in inductor based active cell balancing

Dear Team,

I am trying do inductor based active cell balancing of two cell with 605 and 55% SOC. duty cycle is 50%.

After balancing its balanced to 56.25% which is some amount lower than average of (60and 55).

could anyone tell me why I am getting this type of response.

[Joel Van Sickel]

can you share your model isntead of pictures?

[Pratyay Maity]

Sir,

I tried with matlab simulink and simscape block, one cell getting discharge another not charging.

Please help me resolve this issue.

Thanks,

Pratyay

Answer 1

[Sabin]

Parameterziation of the model is the issue. In Simscape implementation, the sample time for the Simscape circuit is 1 second while the switches are controlled at 25 kHz switching frequency. It just won't work like this. Using N-Channel MOSFET is also not a very good idea in this situation because the balancing process is not very fast and will take ages to simulate the model with high fidelity semiconductors. Probably best to stick with ideal switches (check out this example: https://www.mathworks.com/help/simscape-battery/ug/balance-battery-cells-with-switched-capacitor-method.html ).

In the SPS model it appears to be the same problem. Pulse Generator is using 10 kHz but the plant is simulated at 2 kHz.