Implement Coulomb Counting #46
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jr1221
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jr1221
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awesome. Technically rather than doing get_tick we should eventually read the time increment register in the 2950. But this is good enough for our purposes probably.
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| // Coulomb Counting | ||
| // SoC(t) = SoC(t-1) + I(t)/Qn * (t1 - t0) |
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the order of operations below is different, coreect? THis makes it look like the divide by capacity happens to I(t) then its multiplied by delta t
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Yes, but the order of the multiplication and division does not affect result so its the same
Core/Src/soc.c
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| // SoC(t) = SoC(t-1) + I(t)/Qn * (t1 - t0) | ||
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| float last_soc = analyzer->soc; | ||
| float curr_time = (float)HAL_GetTick(); // in milliseconds |
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dont we need to convert hal_gettick to ms technically?
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Not sure if we should be using tx_time_get() (converted to milliseconds) instead of HAL_GetTick() here, since this code runs in a ThreadX task.
Core/Src/soc.c
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| float current = hv_plate->pack_current; // in Amperes | ||
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| float soc = last_soc + (current * delta_time) / FULL_CAPACITY_AH; |
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If the ADBMS2950 reports positive current during discharge, the current sign may need to be inverted before applying this formula. Otherwise, SOC would increase during discharge.
Changes
Added calculation for pack SoC as a result of Coulomb counting with a look-up table at start up in new file
soc.c.To Do
Any remaining things that need to get done
-[ ] Cell profiling with the P50Bs
-[ ] Potentially incorporate pack average temp to have a more accurate estimate of the pack SoC?
Checklist
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ChecksandFiles changedtabs.Please reach out to your Project Lead if anything is unclear.
Please request reviewers and ping on slack only after you've gone through this whole checklist.
Closes #5